---
_id: '328'
abstract:
- lang: eng
text: The drag of turbulent flows can be drastically decreased by adding small amounts
of high molecular weight polymers. While drag reduction initially increases with
polymer concentration, it eventually saturates to what is known as the maximum
drag reduction (MDR) asymptote; this asymptote is generally attributed to the
dynamics being reduced to a marginal yet persistent state of subdued turbulent
motion. Contrary to this accepted view, we show that, for an appropriate choice
of parameters, polymers can reduce the drag beyond the suggested asymptotic limit,
eliminating turbulence and giving way to laminar flow. At higher polymer concentrations,
however, the laminar state becomes unstable, resulting in a fluctuating flow with
the characteristic drag of the MDR asymptote. Our findings indicate that the asymptotic
state is hence dynamically disconnected from ordinary turbulence. © 2018 American
Physical Society.
acknowledged_ssus:
- _id: SSU
acknowledgement: The authors thank Philipp Maier and the IST Austria workshop for
their dedicated technical support.
article_number: '124501'
article_processing_charge: No
author:
- first_name: George H
full_name: Choueiri, George H
id: 448BD5BC-F248-11E8-B48F-1D18A9856A87
last_name: Choueiri
- first_name: Jose M
full_name: Lopez Alonso, Jose M
id: 40770848-F248-11E8-B48F-1D18A9856A87
last_name: Lopez Alonso
orcid: 0000-0002-0384-2022
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Choueiri GH, Lopez Alonso JM, Hof B. Exceeding the asymptotic limit of polymer
drag reduction. Physical Review Letters. 2018;120(12). doi:10.1103/PhysRevLett.120.124501
apa: Choueiri, G. H., Lopez Alonso, J. M., & Hof, B. (2018). Exceeding the asymptotic
limit of polymer drag reduction. Physical Review Letters. American Physical
Society. https://doi.org/10.1103/PhysRevLett.120.124501
chicago: Choueiri, George H, Jose M Lopez Alonso, and Björn Hof. “Exceeding the
Asymptotic Limit of Polymer Drag Reduction.” Physical Review Letters. American
Physical Society, 2018. https://doi.org/10.1103/PhysRevLett.120.124501.
ieee: G. H. Choueiri, J. M. Lopez Alonso, and B. Hof, “Exceeding the asymptotic
limit of polymer drag reduction,” Physical Review Letters, vol. 120, no.
12. American Physical Society, 2018.
ista: Choueiri GH, Lopez Alonso JM, Hof B. 2018. Exceeding the asymptotic limit
of polymer drag reduction. Physical Review Letters. 120(12), 124501.
mla: Choueiri, George H., et al. “Exceeding the Asymptotic Limit of Polymer Drag
Reduction.” Physical Review Letters, vol. 120, no. 12, 124501, American
Physical Society, 2018, doi:10.1103/PhysRevLett.120.124501.
short: G.H. Choueiri, J.M. Lopez Alonso, B. Hof, Physical Review Letters 120 (2018).
date_created: 2018-12-11T11:45:51Z
date_published: 2018-03-19T00:00:00Z
date_updated: 2023-10-10T13:27:44Z
day: '19'
department:
- _id: BjHo
doi: 10.1103/PhysRevLett.120.124501
ec_funded: 1
external_id:
isi:
- '000427804000005'
intvolume: ' 120'
isi: 1
issue: '12'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1703.06271
month: '03'
oa: 1
oa_version: Preprint
project:
- _id: 25681D80-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '291734'
name: International IST Postdoc Fellowship Programme
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '306589'
name: Decoding the complexity of turbulence at its origin
publication: Physical Review Letters
publication_status: published
publisher: American Physical Society
publist_id: '7537'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Exceeding the asymptotic limit of polymer drag reduction
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 120
year: '2018'
...
---
_id: '136'
abstract:
- lang: eng
text: Recent studies suggest that unstable, nonchaotic solutions of the Navier-Stokes
equation may provide deep insights into fluid turbulence. In this article, we
present a combined experimental and numerical study exploring the dynamical role
of unstable equilibrium solutions and their invariant manifolds in a weakly turbulent,
electromagnetically driven, shallow fluid layer. Identifying instants when turbulent
evolution slows down, we compute 31 unstable equilibria of a realistic two-dimensional
model of the flow. We establish the dynamical relevance of these unstable equilibria
by showing that they are closely visited by the turbulent flow. We also establish
the dynamical relevance of unstable manifolds by verifying that they are shadowed
by turbulent trajectories departing from the neighborhoods of unstable equilibria
over large distances in state space.
article_processing_charge: No
author:
- first_name: Balachandra
full_name: Suri, Balachandra
id: 47A5E706-F248-11E8-B48F-1D18A9856A87
last_name: Suri
- first_name: Jeffrey
full_name: Tithof, Jeffrey
last_name: Tithof
- first_name: Roman
full_name: Grigoriev, Roman
last_name: Grigoriev
- first_name: Michael
full_name: Schatz, Michael
last_name: Schatz
citation:
ama: Suri B, Tithof J, Grigoriev R, Schatz M. Unstable equilibria and invariant
manifolds in quasi-two-dimensional Kolmogorov-like flow. Physical Review E.
2018;98(2). doi:10.1103/PhysRevE.98.023105
apa: Suri, B., Tithof, J., Grigoriev, R., & Schatz, M. (2018). Unstable equilibria
and invariant manifolds in quasi-two-dimensional Kolmogorov-like flow. Physical
Review E. American Physical Society. https://doi.org/10.1103/PhysRevE.98.023105
chicago: Suri, Balachandra, Jeffrey Tithof, Roman Grigoriev, and Michael Schatz.
“Unstable Equilibria and Invariant Manifolds in Quasi-Two-Dimensional Kolmogorov-like
Flow.” Physical Review E. American Physical Society, 2018. https://doi.org/10.1103/PhysRevE.98.023105.
ieee: B. Suri, J. Tithof, R. Grigoriev, and M. Schatz, “Unstable equilibria and
invariant manifolds in quasi-two-dimensional Kolmogorov-like flow,” Physical
Review E, vol. 98, no. 2. American Physical Society, 2018.
ista: Suri B, Tithof J, Grigoriev R, Schatz M. 2018. Unstable equilibria and invariant
manifolds in quasi-two-dimensional Kolmogorov-like flow. Physical Review E. 98(2).
mla: Suri, Balachandra, et al. “Unstable Equilibria and Invariant Manifolds in Quasi-Two-Dimensional
Kolmogorov-like Flow.” Physical Review E, vol. 98, no. 2, American Physical
Society, 2018, doi:10.1103/PhysRevE.98.023105.
short: B. Suri, J. Tithof, R. Grigoriev, M. Schatz, Physical Review E 98 (2018).
date_created: 2018-12-11T11:44:49Z
date_published: 2018-08-13T00:00:00Z
date_updated: 2023-10-10T13:29:10Z
day: '13'
department:
- _id: BjHo
doi: 10.1103/PhysRevE.98.023105
external_id:
arxiv:
- '1808.02088'
isi:
- '000441466800010'
intvolume: ' 98'
isi: 1
issue: '2'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1808.02088
month: '08'
oa: 1
oa_version: Submitted Version
publication: Physical Review E
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Unstable equilibria and invariant manifolds in quasi-two-dimensional Kolmogorov-like
flow
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 98
year: '2018'
...
---
_id: '422'
abstract:
- lang: eng
text: We show that a rather simple, steady modification of the streamwise velocity
profile in a pipe can lead to a complete collapse of turbulence and the flow fully
relaminarizes. Two different devices, a stationary obstacle (inset) and a device
which injects fluid through an annular gap close to the wall, are used to control
the flow. Both devices modify the streamwise velocity profile such that the flow
in the center of the pipe is decelerated and the flow in the near wall region
is accelerated. We present measurements with stereoscopic particle image velocimetry
to investigate and capture the development of the relaminarizing flow downstream
these devices and the specific circumstances responsible for relaminarization.
We find total relaminarization up to Reynolds numbers of 6000, where the skin
friction in the far downstream distance is reduced by a factor of 3.4 due to relaminarization.
In a smooth straight pipe the flow remains completely laminar downstream of the
control. Furthermore, we show that transient (temporary) relaminarization in a
spatially confined region right downstream the devices occurs also at much higher
Reynolds numbers, accompanied by a significant local skin friction drag reduction.
The underlying physical mechanism of relaminarization is attributed to a weakening
of the near-wall turbulence production cycle.
article_processing_charge: Yes (via OA deal)
author:
- first_name: Jakob
full_name: Kühnen, Jakob
id: 3A47AE32-F248-11E8-B48F-1D18A9856A87
last_name: Kühnen
orcid: 0000-0003-4312-0179
- first_name: Davide
full_name: Scarselli, Davide
id: 40315C30-F248-11E8-B48F-1D18A9856A87
last_name: Scarselli
orcid: 0000-0001-5227-4271
- first_name: Markus
full_name: Schaner, Markus
id: 316CE034-F248-11E8-B48F-1D18A9856A87
last_name: Schaner
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Kühnen J, Scarselli D, Schaner M, Hof B. Relaminarization by steady modification
of the streamwise velocity profile in a pipe. Flow Turbulence and Combustion.
2018;100(4):919-942. doi:10.1007/s10494-018-9896-4
apa: Kühnen, J., Scarselli, D., Schaner, M., & Hof, B. (2018). Relaminarization
by steady modification of the streamwise velocity profile in a pipe. Flow Turbulence
and Combustion. Springer. https://doi.org/10.1007/s10494-018-9896-4
chicago: Kühnen, Jakob, Davide Scarselli, Markus Schaner, and Björn Hof. “Relaminarization
by Steady Modification of the Streamwise Velocity Profile in a Pipe.” Flow
Turbulence and Combustion. Springer, 2018. https://doi.org/10.1007/s10494-018-9896-4.
ieee: J. Kühnen, D. Scarselli, M. Schaner, and B. Hof, “Relaminarization by steady
modification of the streamwise velocity profile in a pipe,” Flow Turbulence
and Combustion, vol. 100, no. 4. Springer, pp. 919–942, 2018.
ista: Kühnen J, Scarselli D, Schaner M, Hof B. 2018. Relaminarization by steady
modification of the streamwise velocity profile in a pipe. Flow Turbulence and
Combustion. 100(4), 919–942.
mla: Kühnen, Jakob, et al. “Relaminarization by Steady Modification of the Streamwise
Velocity Profile in a Pipe.” Flow Turbulence and Combustion, vol. 100,
no. 4, Springer, 2018, pp. 919–42, doi:10.1007/s10494-018-9896-4.
short: J. Kühnen, D. Scarselli, M. Schaner, B. Hof, Flow Turbulence and Combustion
100 (2018) 919–942.
date_created: 2018-12-11T11:46:23Z
date_published: 2018-01-01T00:00:00Z
date_updated: 2024-03-27T23:30:36Z
day: '01'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.1007/s10494-018-9896-4
ec_funded: 1
external_id:
isi:
- '000433113900004'
file:
- access_level: open_access
checksum: d7c0bade150faabca150b0a9986e60ca
content_type: application/pdf
creator: dernst
date_created: 2018-12-17T15:52:37Z
date_updated: 2020-07-14T12:46:25Z
file_id: '5717'
file_name: 2018_FlowTurbulenceCombust_Kuehnen.pdf
file_size: 2210020
relation: main_file
file_date_updated: 2020-07-14T12:46:25Z
has_accepted_license: '1'
intvolume: ' 100'
isi: 1
issue: '4'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
page: 919 - 942
project:
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '306589'
name: Decoding the complexity of turbulence at its origin
publication: Flow Turbulence and Combustion
publication_status: published
publisher: Springer
publist_id: '7401'
quality_controlled: '1'
related_material:
record:
- id: '7258'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: Relaminarization by steady modification of the streamwise velocity profile
in a pipe
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 100
year: '2018'
...
---
_id: '461'
abstract:
- lang: eng
text: Turbulence is the major cause of friction losses in transport processes and
it is responsible for a drastic drag increase in flows over bounding surfaces.
While much effort is invested into developing ways to control and reduce turbulence
intensities, so far no methods exist to altogether eliminate turbulence if velocities
are sufficiently large. We demonstrate for pipe flow that appropriate distortions
to the velocity profile lead to a complete collapse of turbulence and subsequently
friction losses are reduced by as much as 90%. Counterintuitively, the return
to laminar motion is accomplished by initially increasing turbulence intensities
or by transiently amplifying wall shear. Since neither the Reynolds number nor
the shear stresses decrease (the latter often increase), these measures are not
indicative of turbulence collapse. Instead, an amplification mechanism measuring
the interaction between eddies and the mean shear is found to set a threshold
below which turbulence is suppressed beyond recovery.
acknowledgement: We acknowledge the European Research Council under the European Union’s
Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement 306589, the European
Research Council (ERC) under the European Union’s Horizon 2020 research and innovation
programme (grant agreement no. 737549) and the Deutsche Forschungsgemeinschaft (Project
No. FOR 1182) for financial support. We thank our technician P. Maier for providing
highly valuable ideas and greatly supporting us in all technical aspects. We thank
M. Schaner for technical drawings, construction and design. We thank M. Schwegel
for a Matlab code to post-process experimental data.
article_processing_charge: No
author:
- first_name: Jakob
full_name: Kühnen, Jakob
id: 3A47AE32-F248-11E8-B48F-1D18A9856A87
last_name: Kühnen
orcid: 0000-0003-4312-0179
- first_name: Baofang
full_name: Song, Baofang
last_name: Song
- first_name: Davide
full_name: Scarselli, Davide
id: 40315C30-F248-11E8-B48F-1D18A9856A87
last_name: Scarselli
orcid: 0000-0001-5227-4271
- first_name: Nazmi B
full_name: Budanur, Nazmi B
id: 3EA1010E-F248-11E8-B48F-1D18A9856A87
last_name: Budanur
orcid: 0000-0003-0423-5010
- first_name: Michael
full_name: Riedl, Michael
id: 3BE60946-F248-11E8-B48F-1D18A9856A87
last_name: Riedl
orcid: 0000-0003-4844-6311
- first_name: Ashley
full_name: Willis, Ashley
last_name: Willis
- first_name: Marc
full_name: Avila, Marc
last_name: Avila
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Kühnen J, Song B, Scarselli D, et al. Destabilizing turbulence in pipe flow.
Nature Physics. 2018;14:386-390. doi:10.1038/s41567-017-0018-3
apa: Kühnen, J., Song, B., Scarselli, D., Budanur, N. B., Riedl, M., Willis, A.,
… Hof, B. (2018). Destabilizing turbulence in pipe flow. Nature Physics.
Nature Publishing Group. https://doi.org/10.1038/s41567-017-0018-3
chicago: Kühnen, Jakob, Baofang Song, Davide Scarselli, Nazmi B Budanur, Michael
Riedl, Ashley Willis, Marc Avila, and Björn Hof. “Destabilizing Turbulence in
Pipe Flow.” Nature Physics. Nature Publishing Group, 2018. https://doi.org/10.1038/s41567-017-0018-3.
ieee: J. Kühnen et al., “Destabilizing turbulence in pipe flow,” Nature
Physics, vol. 14. Nature Publishing Group, pp. 386–390, 2018.
ista: Kühnen J, Song B, Scarselli D, Budanur NB, Riedl M, Willis A, Avila M, Hof
B. 2018. Destabilizing turbulence in pipe flow. Nature Physics. 14, 386–390.
mla: Kühnen, Jakob, et al. “Destabilizing Turbulence in Pipe Flow.” Nature Physics,
vol. 14, Nature Publishing Group, 2018, pp. 386–90, doi:10.1038/s41567-017-0018-3.
short: J. Kühnen, B. Song, D. Scarselli, N.B. Budanur, M. Riedl, A. Willis, M. Avila,
B. Hof, Nature Physics 14 (2018) 386–390.
date_created: 2018-12-11T11:46:36Z
date_published: 2018-01-08T00:00:00Z
date_updated: 2024-03-27T23:30:36Z
day: '08'
department:
- _id: BjHo
doi: 10.1038/s41567-017-0018-3
ec_funded: 1
external_id:
isi:
- '000429434100020'
intvolume: ' 14'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1711.06543
month: '01'
oa: 1
oa_version: Preprint
page: 386-390
project:
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '306589'
name: Decoding the complexity of turbulence at its origin
- _id: 25104D44-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '737549'
name: Eliminating turbulence in oil pipelines
publication: Nature Physics
publication_status: published
publisher: Nature Publishing Group
publist_id: '7360'
quality_controlled: '1'
related_material:
record:
- id: '12726'
relation: dissertation_contains
status: public
- id: '14530'
relation: dissertation_contains
status: public
- id: '7258'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: Destabilizing turbulence in pipe flow
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 14
year: '2018'
...
---
_id: '1211'
abstract:
- lang: eng
text: Systems such as fluid flows in channels and pipes or the complex Ginzburg–Landau
system, defined over periodic domains, exhibit both continuous symmetries, translational
and rotational, as well as discrete symmetries under spatial reflections or complex
conjugation. The simplest, and very common symmetry of this type is the equivariance
of the defining equations under the orthogonal group O(2). We formulate a novel
symmetry reduction scheme for such systems by combining the method of slices with
invariant polynomial methods, and show how it works by applying it to the Kuramoto–Sivashinsky
system in one spatial dimension. As an example, we track a relative periodic orbit
through a sequence of bifurcations to the onset of chaos. Within the symmetry-reduced
state space we are able to compute and visualize the unstable manifolds of relative
periodic orbits, their torus bifurcations, a transition to chaos via torus breakdown,
and heteroclinic connections between various relative periodic orbits. It would
be very hard to carry through such analysis in the full state space, without a
symmetry reduction such as the one we present here.
acknowledgement: 'This work was supported by the family of late G. Robinson, Jr. and
NSF Grant DMS-1211827. '
author:
- first_name: Nazmi B
full_name: Budanur, Nazmi B
id: 3EA1010E-F248-11E8-B48F-1D18A9856A87
last_name: Budanur
orcid: 0000-0003-0423-5010
- first_name: Predrag
full_name: Cvitanović, Predrag
last_name: Cvitanović
citation:
ama: Budanur NB, Cvitanović P. Unstable manifolds of relative periodic orbits in
the symmetry reduced state space of the Kuramoto–Sivashinsky system. Journal
of Statistical Physics. 2017;167(3-4):636-655. doi:10.1007/s10955-016-1672-z
apa: Budanur, N. B., & Cvitanović, P. (2017). Unstable manifolds of relative
periodic orbits in the symmetry reduced state space of the Kuramoto–Sivashinsky
system. Journal of Statistical Physics. Springer. https://doi.org/10.1007/s10955-016-1672-z
chicago: Budanur, Nazmi B, and Predrag Cvitanović. “Unstable Manifolds of Relative
Periodic Orbits in the Symmetry Reduced State Space of the Kuramoto–Sivashinsky
System.” Journal of Statistical Physics. Springer, 2017. https://doi.org/10.1007/s10955-016-1672-z.
ieee: N. B. Budanur and P. Cvitanović, “Unstable manifolds of relative periodic
orbits in the symmetry reduced state space of the Kuramoto–Sivashinsky system,”
Journal of Statistical Physics, vol. 167, no. 3–4. Springer, pp. 636–655,
2017.
ista: Budanur NB, Cvitanović P. 2017. Unstable manifolds of relative periodic orbits
in the symmetry reduced state space of the Kuramoto–Sivashinsky system. Journal
of Statistical Physics. 167(3–4), 636–655.
mla: Budanur, Nazmi B., and Predrag Cvitanović. “Unstable Manifolds of Relative
Periodic Orbits in the Symmetry Reduced State Space of the Kuramoto–Sivashinsky
System.” Journal of Statistical Physics, vol. 167, no. 3–4, Springer, 2017,
pp. 636–55, doi:10.1007/s10955-016-1672-z.
short: N.B. Budanur, P. Cvitanović, Journal of Statistical Physics 167 (2017) 636–655.
date_created: 2018-12-11T11:50:44Z
date_published: 2017-05-01T00:00:00Z
date_updated: 2021-01-12T06:49:07Z
day: '01'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.1007/s10955-016-1672-z
file:
- access_level: open_access
checksum: 3e971d09eb167761aa0888ed415b0056
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:18:01Z
date_updated: 2020-07-14T12:44:39Z
file_id: '5319'
file_name: IST-2017-782-v1+1_BudCvi15.pdf
file_size: 2820207
relation: main_file
file_date_updated: 2020-07-14T12:44:39Z
has_accepted_license: '1'
intvolume: ' 167'
issue: 3-4
language:
- iso: eng
month: '05'
oa: 1
oa_version: Submitted Version
page: 636-655
publication: Journal of Statistical Physics
publication_status: published
publisher: Springer
publist_id: '6136'
pubrep_id: '782'
quality_controlled: '1'
scopus_import: 1
status: public
title: Unstable manifolds of relative periodic orbits in the symmetry reduced state
space of the Kuramoto–Sivashinsky system
type: journal_article
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 167
year: '2017'
...
---
_id: '513'
abstract:
- lang: eng
text: 'We present an experimental setup that creates a shear flow with zero mean
advection velocity achieved by counterbalancing the nonzero streamwise pressure
gradient by moving boundaries, which generates plane Couette-Poiseuille flow.
We obtain experimental results in the transitional regime for this flow. Using
flow visualization, we characterize the subcritical transition to turbulence in
Couette-Poiseuille flow and show the existence of turbulent spots generated by
a permanent perturbation. Due to the zero mean advection velocity of the base
profile, these turbulent structures are nearly stationary. We distinguish two
regions of the turbulent spot: the active turbulent core, which is characterized
by waviness of the streaks similar to traveling waves, and the surrounding region,
which includes in addition the weak undisturbed streaks and oblique waves at the
laminar-turbulent interface. We also study the dependence of the size of these
two regions on Reynolds number. Finally, we show that the traveling waves move
in the downstream (Poiseuille) direction.'
article_number: '043904'
author:
- first_name: Lukasz
full_name: Klotz, Lukasz
id: 2C9AF1C2-F248-11E8-B48F-1D18A9856A87
last_name: Klotz
orcid: 0000-0003-1740-7635
- first_name: Grégoire M
full_name: Lemoult, Grégoire M
id: 4787FE80-F248-11E8-B48F-1D18A9856A87
last_name: Lemoult
- first_name: Idalia
full_name: Frontczak, Idalia
last_name: Frontczak
- first_name: Laurette
full_name: Tuckerman, Laurette
last_name: Tuckerman
- first_name: José
full_name: Wesfreid, José
last_name: Wesfreid
citation:
ama: 'Klotz L, Lemoult GM, Frontczak I, Tuckerman L, Wesfreid J. Couette-Poiseuille
flow experiment with zero mean advection velocity: Subcritical transition to turbulence.
Physical Review Fluids. 2017;2(4). doi:10.1103/PhysRevFluids.2.043904'
apa: 'Klotz, L., Lemoult, G. M., Frontczak, I., Tuckerman, L., & Wesfreid, J.
(2017). Couette-Poiseuille flow experiment with zero mean advection velocity:
Subcritical transition to turbulence. Physical Review Fluids. American
Physical Society. https://doi.org/10.1103/PhysRevFluids.2.043904'
chicago: 'Klotz, Lukasz, Grégoire M Lemoult, Idalia Frontczak, Laurette Tuckerman,
and José Wesfreid. “Couette-Poiseuille Flow Experiment with Zero Mean Advection
Velocity: Subcritical Transition to Turbulence.” Physical Review Fluids.
American Physical Society, 2017. https://doi.org/10.1103/PhysRevFluids.2.043904.'
ieee: 'L. Klotz, G. M. Lemoult, I. Frontczak, L. Tuckerman, and J. Wesfreid, “Couette-Poiseuille
flow experiment with zero mean advection velocity: Subcritical transition to turbulence,”
Physical Review Fluids, vol. 2, no. 4. American Physical Society, 2017.'
ista: 'Klotz L, Lemoult GM, Frontczak I, Tuckerman L, Wesfreid J. 2017. Couette-Poiseuille
flow experiment with zero mean advection velocity: Subcritical transition to turbulence.
Physical Review Fluids. 2(4), 043904.'
mla: 'Klotz, Lukasz, et al. “Couette-Poiseuille Flow Experiment with Zero Mean Advection
Velocity: Subcritical Transition to Turbulence.” Physical Review Fluids,
vol. 2, no. 4, 043904, American Physical Society, 2017, doi:10.1103/PhysRevFluids.2.043904.'
short: L. Klotz, G.M. Lemoult, I. Frontczak, L. Tuckerman, J. Wesfreid, Physical
Review Fluids 2 (2017).
date_created: 2018-12-11T11:46:54Z
date_published: 2017-04-01T00:00:00Z
date_updated: 2021-01-12T08:01:16Z
day: '01'
department:
- _id: BjHo
doi: 10.1103/PhysRevFluids.2.043904
intvolume: ' 2'
issue: '4'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1704.02619
month: '04'
oa: 1
oa_version: Preprint
publication: Physical Review Fluids
publication_status: published
publisher: American Physical Society
publist_id: '7306'
quality_controlled: '1'
scopus_import: 1
status: public
title: 'Couette-Poiseuille flow experiment with zero mean advection velocity: Subcritical
transition to turbulence'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 2
year: '2017'
...
---
_id: '651'
abstract:
- lang: eng
text: "Superhydrophobic surfaces reduce the frictional drag between water and solid
materials, but this effect is often temporary. The realization of sustained drag
reduction has applications for water vehicles and pipeline flows.\r\n\r\n"
author:
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: 'Hof B. Fluid dynamics: Water flows out of touch. Nature. 2017;541(7636):161-162.
doi:10.1038/541161a'
apa: 'Hof, B. (2017). Fluid dynamics: Water flows out of touch. Nature. Nature
Publishing Group. https://doi.org/10.1038/541161a'
chicago: 'Hof, Björn. “Fluid Dynamics: Water Flows out of Touch.” Nature.
Nature Publishing Group, 2017. https://doi.org/10.1038/541161a.'
ieee: 'B. Hof, “Fluid dynamics: Water flows out of touch,” Nature, vol. 541,
no. 7636. Nature Publishing Group, pp. 161–162, 2017.'
ista: 'Hof B. 2017. Fluid dynamics: Water flows out of touch. Nature. 541(7636),
161–162.'
mla: 'Hof, Björn. “Fluid Dynamics: Water Flows out of Touch.” Nature, vol.
541, no. 7636, Nature Publishing Group, 2017, pp. 161–62, doi:10.1038/541161a.'
short: B. Hof, Nature 541 (2017) 161–162.
date_created: 2018-12-11T11:47:43Z
date_published: 2017-01-11T00:00:00Z
date_updated: 2021-01-12T08:07:49Z
day: '11'
department:
- _id: BjHo
doi: 10.1038/541161a
intvolume: ' 541'
issue: '7636'
language:
- iso: eng
month: '01'
oa_version: None
page: 161 - 162
publication: Nature
publication_identifier:
issn:
- '00280836'
publication_status: published
publisher: Nature Publishing Group
publist_id: '7116'
quality_controlled: '1'
scopus_import: 1
status: public
title: 'Fluid dynamics: Water flows out of touch'
type: journal_article
user_id: 4435EBFC-F248-11E8-B48F-1D18A9856A87
volume: 541
year: '2017'
...
---
_id: '662'
abstract:
- lang: eng
text: 'We report a direct-numerical-simulation study of the Taylor-Couette flow
in the quasi-Keplerian regime at shear Reynolds numbers up to (105). Quasi-Keplerian
rotating flow has been investigated for decades as a simplified model system to
study the origin of turbulence in accretion disks that is not fully understood.
The flow in this study is axially periodic and thus the experimental end-wall
effects on the stability of the flow are avoided. Using optimal linear perturbations
as initial conditions, our simulations find no sustained turbulence: the strong
initial perturbations distort the velocity profile and trigger turbulence that
eventually decays.'
article_number: '044107'
author:
- first_name: Liang
full_name: Shi, Liang
last_name: Shi
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
- first_name: Markus
full_name: Rampp, Markus
last_name: Rampp
- first_name: Marc
full_name: Avila, Marc
last_name: Avila
citation:
ama: Shi L, Hof B, Rampp M, Avila M. Hydrodynamic turbulence in quasi Keplerian
rotating flows. Physics of Fluids. 2017;29(4). doi:10.1063/1.4981525
apa: Shi, L., Hof, B., Rampp, M., & Avila, M. (2017). Hydrodynamic turbulence
in quasi Keplerian rotating flows. Physics of Fluids. American Institute
of Physics. https://doi.org/10.1063/1.4981525
chicago: Shi, Liang, Björn Hof, Markus Rampp, and Marc Avila. “Hydrodynamic Turbulence
in Quasi Keplerian Rotating Flows.” Physics of Fluids. American Institute
of Physics, 2017. https://doi.org/10.1063/1.4981525.
ieee: L. Shi, B. Hof, M. Rampp, and M. Avila, “Hydrodynamic turbulence in quasi
Keplerian rotating flows,” Physics of Fluids, vol. 29, no. 4. American
Institute of Physics, 2017.
ista: Shi L, Hof B, Rampp M, Avila M. 2017. Hydrodynamic turbulence in quasi Keplerian
rotating flows. Physics of Fluids. 29(4), 044107.
mla: Shi, Liang, et al. “Hydrodynamic Turbulence in Quasi Keplerian Rotating Flows.”
Physics of Fluids, vol. 29, no. 4, 044107, American Institute of Physics,
2017, doi:10.1063/1.4981525.
short: L. Shi, B. Hof, M. Rampp, M. Avila, Physics of Fluids 29 (2017).
date_created: 2018-12-11T11:47:47Z
date_published: 2017-04-01T00:00:00Z
date_updated: 2021-01-12T08:08:15Z
day: '01'
department:
- _id: BjHo
doi: 10.1063/1.4981525
intvolume: ' 29'
issue: '4'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1703.01714
month: '04'
oa: 1
oa_version: Submitted Version
project:
- _id: 2511D90C-B435-11E9-9278-68D0E5697425
grant_number: SFB 963 TP A8
name: Astrophysical instability of currents and turbulences
publication: Physics of Fluids
publication_identifier:
issn:
- '10706631'
publication_status: published
publisher: American Institute of Physics
publist_id: '7072'
quality_controlled: '1'
scopus_import: 1
status: public
title: Hydrodynamic turbulence in quasi Keplerian rotating flows
type: journal_article
user_id: 4435EBFC-F248-11E8-B48F-1D18A9856A87
volume: 29
year: '2017'
...
---
_id: '1160'
abstract:
- lang: eng
text: 'We investigate fundamental nonlinear dynamics of ferrofluidic Taylor-Couette
flow - flow confined be-tween two concentric independently rotating cylinders
- consider small aspect ratio by solving the ferro-hydrodynamical equations, carrying
out systematic bifurcation analysis. Without magnetic field, we find steady flow
patterns, previously observed with a simple fluid, such as those containing normal
one- or two vortex cells, as well as anomalous one-cell and twin-cell flow states.
However, when a symmetry-breaking transverse magnetic field is present, all flow
states exhibit stimulated, finite two-fold mode. Various bifurcations between
steady and unsteady states can occur, corresponding to the transitions between
the two-cell and one-cell states. While unsteady, axially oscillating flow states
can arise, we also detect the emergence of new unsteady flow states. In particular,
we uncover two new states: one contains only the azimuthally oscillating solution
in the configuration of the twin-cell flow state, and an-other a rotating flow
state. Topologically, these flow states are a limit cycle and a quasiperiodic
solution on a two-torus, respectively. Emergence of new flow states in addition
to observed ones with classical fluid, indicates that richer but potentially more
controllable dynamics in ferrofluidic flows, as such flow states depend on the
external magnetic field.'
article_number: '40012'
article_processing_charge: No
author:
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
- first_name: Younghae
full_name: Do, Younghae
last_name: Do
- first_name: Ying
full_name: Lai, Ying
last_name: Lai
citation:
ama: Altmeyer S, Do Y, Lai Y. Dynamics of ferrofluidic flow in the Taylor-Couette
system with a small aspect ratio. Scientific Reports. 2017;7. doi:10.1038/srep40012
apa: Altmeyer, S., Do, Y., & Lai, Y. (2017). Dynamics of ferrofluidic flow in
the Taylor-Couette system with a small aspect ratio. Scientific Reports.
Nature Publishing Group. https://doi.org/10.1038/srep40012
chicago: Altmeyer, Sebastian, Younghae Do, and Ying Lai. “Dynamics of Ferrofluidic
Flow in the Taylor-Couette System with a Small Aspect Ratio.” Scientific Reports.
Nature Publishing Group, 2017. https://doi.org/10.1038/srep40012.
ieee: S. Altmeyer, Y. Do, and Y. Lai, “Dynamics of ferrofluidic flow in the Taylor-Couette
system with a small aspect ratio,” Scientific Reports, vol. 7. Nature Publishing
Group, 2017.
ista: Altmeyer S, Do Y, Lai Y. 2017. Dynamics of ferrofluidic flow in the Taylor-Couette
system with a small aspect ratio. Scientific Reports. 7, 40012.
mla: Altmeyer, Sebastian, et al. “Dynamics of Ferrofluidic Flow in the Taylor-Couette
System with a Small Aspect Ratio.” Scientific Reports, vol. 7, 40012, Nature
Publishing Group, 2017, doi:10.1038/srep40012.
short: S. Altmeyer, Y. Do, Y. Lai, Scientific Reports 7 (2017).
date_created: 2018-12-11T11:50:28Z
date_published: 2017-01-06T00:00:00Z
date_updated: 2023-09-20T11:28:49Z
day: '06'
ddc:
- '532'
department:
- _id: BjHo
doi: 10.1038/srep40012
external_id:
isi:
- '000391269700001'
file:
- access_level: open_access
checksum: 694aa70399444570825099c1a7ec91f2
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:10:16Z
date_updated: 2020-07-14T12:44:36Z
file_id: '4802'
file_name: IST-2017-743-v1+1_srep40012.pdf
file_size: 4546835
relation: main_file
file_date_updated: 2020-07-14T12:44:36Z
has_accepted_license: '1'
intvolume: ' 7'
isi: 1
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
publication: Scientific Reports
publication_identifier:
issn:
- '20452322'
publication_status: published
publisher: Nature Publishing Group
publist_id: '6198'
pubrep_id: '743'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Dynamics of ferrofluidic flow in the Taylor-Couette system with a small aspect
ratio
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 7
year: '2017'
...
---
_id: '1087'
abstract:
- lang: eng
text: Using extensive direct numerical simulations, the dynamics of laminar-turbulent
fronts in pipe flow is investigated for Reynolds numbers between and 5500. We
here investigate the physical distinction between the fronts of weak and strong
slugs both by analysing the turbulent kinetic energy budget and by comparing the
downstream front motion to the advection speed of bulk turbulent structures. Our
study shows that weak downstream fronts travel slower than turbulent structures
in the bulk and correspond to decaying turbulence at the front. At the downstream
front speed becomes faster than the advection speed, marking the onset of strong
fronts. In contrast to weak fronts, turbulent eddies are generated at strong fronts
by feeding on the downstream laminar flow. Our study also suggests that temporal
fluctuations of production and dissipation at the downstream laminar-turbulent
front drive the dynamical switches between the two types of front observed up
to.
acknowledged_ssus:
- _id: ScienComp
article_processing_charge: No
author:
- first_name: Baofang
full_name: Song, Baofang
last_name: Song
- first_name: Dwight
full_name: Barkley, Dwight
last_name: Barkley
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
- first_name: Marc
full_name: Avila, Marc
last_name: Avila
citation:
ama: Song B, Barkley D, Hof B, Avila M. Speed and structure of turbulent fronts
in pipe flow. Journal of Fluid Mechanics. 2017;813:1045-1059. doi:10.1017/jfm.2017.14
apa: Song, B., Barkley, D., Hof, B., & Avila, M. (2017). Speed and structure
of turbulent fronts in pipe flow. Journal of Fluid Mechanics. Cambridge
University Press. https://doi.org/10.1017/jfm.2017.14
chicago: Song, Baofang, Dwight Barkley, Björn Hof, and Marc Avila. “Speed and Structure
of Turbulent Fronts in Pipe Flow.” Journal of Fluid Mechanics. Cambridge
University Press, 2017. https://doi.org/10.1017/jfm.2017.14.
ieee: B. Song, D. Barkley, B. Hof, and M. Avila, “Speed and structure of turbulent
fronts in pipe flow,” Journal of Fluid Mechanics, vol. 813. Cambridge University
Press, pp. 1045–1059, 2017.
ista: Song B, Barkley D, Hof B, Avila M. 2017. Speed and structure of turbulent
fronts in pipe flow. Journal of Fluid Mechanics. 813, 1045–1059.
mla: Song, Baofang, et al. “Speed and Structure of Turbulent Fronts in Pipe Flow.”
Journal of Fluid Mechanics, vol. 813, Cambridge University Press, 2017,
pp. 1045–59, doi:10.1017/jfm.2017.14.
short: B. Song, D. Barkley, B. Hof, M. Avila, Journal of Fluid Mechanics 813 (2017)
1045–1059.
date_created: 2018-12-11T11:50:04Z
date_published: 2017-02-25T00:00:00Z
date_updated: 2023-09-20T11:47:22Z
day: '25'
department:
- _id: BjHo
doi: 10.1017/jfm.2017.14
ec_funded: 1
external_id:
isi:
- '000394376400044'
intvolume: ' 813'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1603.04077
month: '02'
oa: 1
oa_version: Submitted Version
page: 1045 - 1059
project:
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '306589'
name: Decoding the complexity of turbulence at its origin
publication: Journal of Fluid Mechanics
publication_identifier:
issn:
- '00221120'
publication_status: published
publisher: Cambridge University Press
publist_id: '6290'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Speed and structure of turbulent fronts in pipe flow
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 813
year: '2017'
...
---
_id: '1021'
abstract:
- lang: eng
text: Most flows in nature and engineering are turbulent because of their large
velocities and spatial scales. Laboratory experiments on rotating quasi-Keplerian
flows, for which the angular velocity decreases radially but the angular momentum
increases, are however laminar at Reynolds numbers exceeding one million. This
is in apparent contradiction to direct numerical simulations showing that in these
experiments turbulence transition is triggered by the axial boundaries. We here
show numerically that as the Reynolds number increases, turbulence becomes progressively
confined to the boundary layers and the flow in the bulk fully relaminarizes.
Our findings support that turbulence is unlikely to occur in isothermal constant-density
quasi-Keplerian flows.
article_processing_charge: No
author:
- first_name: Jose M
full_name: Lopez Alonso, Jose M
id: 40770848-F248-11E8-B48F-1D18A9856A87
last_name: Lopez Alonso
orcid: 0000-0002-0384-2022
- first_name: Marc
full_name: Avila, Marc
last_name: Avila
citation:
ama: Lopez Alonso JM, Avila M. Boundary layer turbulence in experiments on quasi
Keplerian flows. Journal of Fluid Mechanics. 2017;817:21-34. doi:10.1017/jfm.2017.109
apa: Lopez Alonso, J. M., & Avila, M. (2017). Boundary layer turbulence in experiments
on quasi Keplerian flows. Journal of Fluid Mechanics. Cambridge University
Press. https://doi.org/10.1017/jfm.2017.109
chicago: Lopez Alonso, Jose M, and Marc Avila. “Boundary Layer Turbulence in Experiments
on Quasi Keplerian Flows.” Journal of Fluid Mechanics. Cambridge University
Press, 2017. https://doi.org/10.1017/jfm.2017.109.
ieee: J. M. Lopez Alonso and M. Avila, “Boundary layer turbulence in experiments
on quasi Keplerian flows,” Journal of Fluid Mechanics, vol. 817. Cambridge
University Press, pp. 21–34, 2017.
ista: Lopez Alonso JM, Avila M. 2017. Boundary layer turbulence in experiments on
quasi Keplerian flows. Journal of Fluid Mechanics. 817, 21–34.
mla: Lopez Alonso, Jose M., and Marc Avila. “Boundary Layer Turbulence in Experiments
on Quasi Keplerian Flows.” Journal of Fluid Mechanics, vol. 817, Cambridge
University Press, 2017, pp. 21–34, doi:10.1017/jfm.2017.109.
short: J.M. Lopez Alonso, M. Avila, Journal of Fluid Mechanics 817 (2017) 21–34.
date_created: 2018-12-11T11:49:44Z
date_published: 2017-04-25T00:00:00Z
date_updated: 2023-09-22T09:39:46Z
day: '25'
department:
- _id: BjHo
doi: 10.1017/jfm.2017.109
external_id:
isi:
- '000398179100006'
intvolume: ' 817'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1608.05527
month: '04'
oa: 1
oa_version: Submitted Version
page: 21 - 34
project:
- _id: 255008E4-B435-11E9-9278-68D0E5697425
grant_number: RGP0065/2012
name: Information processing and computation in fish groups
publication: Journal of Fluid Mechanics
publication_identifier:
issn:
- '00221120'
publication_status: published
publisher: Cambridge University Press
publist_id: '6371'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Boundary layer turbulence in experiments on quasi Keplerian flows
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 817
year: '2017'
...
---
_id: '792'
abstract:
- lang: eng
text: The chaotic dynamics of low-dimensional systems, such as Lorenz or Rössler
flows, is guided by the infinity of periodic orbits embedded in their strange
attractors. Whether this is also the case for the infinite-dimensional dynamics
of Navier–Stokes equations has long been speculated, and is a topic of ongoing
study. Periodic and relative periodic solutions have been shown to be involved
in transitions to turbulence. Their relevance to turbulent dynamics – specifically,
whether periodic orbits play the same role in high-dimensional nonlinear systems
like the Navier–Stokes equations as they do in lower-dimensional systems – is
the focus of the present investigation. We perform here a detailed study of pipe
flow relative periodic orbits with energies and mean dissipations close to turbulent
values. We outline several approaches to reduction of the translational symmetry
of the system. We study pipe flow in a minimal computational cell at Re=2500,
and report a library of invariant solutions found with the aid of the method of
slices. Detailed study of the unstable manifolds of a sample of these solutions
is consistent with the picture that relative periodic orbits are embedded in the
chaotic saddle and that they guide the turbulent dynamics.
article_processing_charge: No
author:
- first_name: Nazmi B
full_name: Budanur, Nazmi B
id: 3EA1010E-F248-11E8-B48F-1D18A9856A87
last_name: Budanur
orcid: 0000-0003-0423-5010
- first_name: Kimberly
full_name: Short, Kimberly
last_name: Short
- first_name: Mohammad
full_name: Farazmand, Mohammad
last_name: Farazmand
- first_name: Ashley
full_name: Willis, Ashley
last_name: Willis
- first_name: Predrag
full_name: Cvitanović, Predrag
last_name: Cvitanović
citation:
ama: Budanur NB, Short K, Farazmand M, Willis A, Cvitanović P. Relative periodic
orbits form the backbone of turbulent pipe flow. Journal of Fluid Mechanics.
2017;833:274-301. doi:10.1017/jfm.2017.699
apa: Budanur, N. B., Short, K., Farazmand, M., Willis, A., & Cvitanović, P.
(2017). Relative periodic orbits form the backbone of turbulent pipe flow. Journal
of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2017.699
chicago: Budanur, Nazmi B, Kimberly Short, Mohammad Farazmand, Ashley Willis, and
Predrag Cvitanović. “Relative Periodic Orbits Form the Backbone of Turbulent Pipe
Flow.” Journal of Fluid Mechanics. Cambridge University Press, 2017. https://doi.org/10.1017/jfm.2017.699.
ieee: N. B. Budanur, K. Short, M. Farazmand, A. Willis, and P. Cvitanović, “Relative
periodic orbits form the backbone of turbulent pipe flow,” Journal of Fluid
Mechanics, vol. 833. Cambridge University Press, pp. 274–301, 2017.
ista: Budanur NB, Short K, Farazmand M, Willis A, Cvitanović P. 2017. Relative periodic
orbits form the backbone of turbulent pipe flow. Journal of Fluid Mechanics. 833,
274–301.
mla: Budanur, Nazmi B., et al. “Relative Periodic Orbits Form the Backbone of Turbulent
Pipe Flow.” Journal of Fluid Mechanics, vol. 833, Cambridge University
Press, 2017, pp. 274–301, doi:10.1017/jfm.2017.699.
short: N.B. Budanur, K. Short, M. Farazmand, A. Willis, P. Cvitanović, Journal of
Fluid Mechanics 833 (2017) 274–301.
date_created: 2018-12-11T11:48:32Z
date_published: 2017-12-25T00:00:00Z
date_updated: 2023-09-27T12:17:35Z
day: '25'
department:
- _id: BjHo
doi: 10.1017/jfm.2017.699
external_id:
isi:
- '000414641700001'
intvolume: ' 833'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1705.03720
month: '12'
oa: 1
oa_version: Submitted Version
page: 274 - 301
project:
- _id: 25636330-B435-11E9-9278-68D0E5697425
grant_number: 11-NSF-1070
name: ROOTS Genome-wide Analysis of Root Traits
publication: Journal of Fluid Mechanics
publication_identifier:
issn:
- '00221120'
publication_status: published
publisher: Cambridge University Press
publist_id: '6862'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Relative periodic orbits form the backbone of turbulent pipe flow
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 833
year: '2017'
...
---
_id: '824'
abstract:
- lang: eng
text: 'In shear flows at transitional Reynolds numbers, localized patches of turbulence,
known as puffs, coexist with the laminar flow. Recently, Avila et al. (Phys. Rev.
Lett., vol. 110, 2013, 224502) discovered two spatially localized relative periodic
solutions for pipe flow, which appeared in a saddle-node bifurcation at low Reynolds
number. Combining slicing methods for continuous symmetry reduction with Poincaré
sections for the first time in a shear flow setting, we compute and visualize
the unstable manifold of the lower-branch solution and show that it extends towards
the neighbourhood of the upper-branch solution. Surprisingly, this connection
even persists far above the bifurcation point and appears to mediate the first
stage of the puff generation: amplification of streamwise localized fluctuations.
When the state-space trajectories on the unstable manifold reach the vicinity
of the upper branch, corresponding fluctuations expand in space and eventually
take the usual shape of a puff.'
article_number: R1
article_processing_charge: No
author:
- first_name: Nazmi B
full_name: Budanur, Nazmi B
id: 3EA1010E-F248-11E8-B48F-1D18A9856A87
last_name: Budanur
orcid: 0000-0003-0423-5010
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Budanur NB, Hof B. Heteroclinic path to spatially localized chaos in pipe flow.
Journal of Fluid Mechanics. 2017;827. doi:10.1017/jfm.2017.516
apa: Budanur, N. B., & Hof, B. (2017). Heteroclinic path to spatially localized
chaos in pipe flow. Journal of Fluid Mechanics. Cambridge University Press.
https://doi.org/10.1017/jfm.2017.516
chicago: Budanur, Nazmi B, and Björn Hof. “Heteroclinic Path to Spatially Localized
Chaos in Pipe Flow.” Journal of Fluid Mechanics. Cambridge University Press,
2017. https://doi.org/10.1017/jfm.2017.516.
ieee: N. B. Budanur and B. Hof, “Heteroclinic path to spatially localized chaos
in pipe flow,” Journal of Fluid Mechanics, vol. 827. Cambridge University
Press, 2017.
ista: Budanur NB, Hof B. 2017. Heteroclinic path to spatially localized chaos in
pipe flow. Journal of Fluid Mechanics. 827, R1.
mla: Budanur, Nazmi B., and Björn Hof. “Heteroclinic Path to Spatially Localized
Chaos in Pipe Flow.” Journal of Fluid Mechanics, vol. 827, R1, Cambridge
University Press, 2017, doi:10.1017/jfm.2017.516.
short: N.B. Budanur, B. Hof, Journal of Fluid Mechanics 827 (2017).
date_created: 2018-12-11T11:48:42Z
date_published: 2017-08-18T00:00:00Z
date_updated: 2023-09-26T16:17:43Z
day: '18'
department:
- _id: BjHo
doi: 10.1017/jfm.2017.516
external_id:
isi:
- '000408326300001'
intvolume: ' 827'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1703.10484
month: '08'
oa: 1
oa_version: Submitted Version
publication: Journal of Fluid Mechanics
publication_identifier:
issn:
- '00221120'
publication_status: published
publisher: Cambridge University Press
publist_id: '6824'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Heteroclinic path to spatially localized chaos in pipe flow
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 827
year: '2017'
...
---
_id: '745'
abstract:
- lang: eng
text: 'Fluid flows in nature and applications are frequently subject to periodic
velocity modulations. Surprisingly, even for the generic case of flow through
a straight pipe, there is little consensus regarding the influence of pulsation
on the transition threshold to turbulence: while most studies predict a monotonically
increasing threshold with pulsation frequency (i.e. Womersley number, ), others
observe a decreasing threshold for identical parameters and only observe an increasing
threshold at low . In the present study we apply recent advances in the understanding
of transition in steady shear flows to pulsating pipe flow. For moderate pulsation
amplitudes we find that the first instability encountered is subcritical (i.e.
requiring finite amplitude disturbances) and gives rise to localized patches of
turbulence (''puffs'') analogous to steady pipe flow. By monitoring the impact
of pulsation on the lifetime of turbulence we map the onset of turbulence in parameter
space. Transition in pulsatile flow can be separated into three regimes. At small
Womersley numbers the dynamics is dominated by the decay turbulence suffers during
the slower part of the cycle and hence transition is delayed significantly. As
shown in this regime thresholds closely agree with estimates based on a quasi-steady
flow assumption only taking puff decay rates into account. The transition point
predicted in the zero limit equals to the critical point for steady pipe flow
offset by the oscillation Reynolds number (i.e. the dimensionless oscillation
amplitude). In the high frequency limit on the other hand, puff lifetimes are
identical to those in steady pipe flow and hence the transition threshold appears
to be unaffected by flow pulsation. In the intermediate frequency regime the transition
threshold sharply drops (with increasing ) from the decay dominated (quasi-steady)
threshold to the steady pipe flow level.'
article_processing_charge: No
author:
- first_name: Duo
full_name: Xu, Duo
id: 3454D55E-F248-11E8-B48F-1D18A9856A87
last_name: Xu
- first_name: Sascha
full_name: Warnecke, Sascha
last_name: Warnecke
- first_name: Baofang
full_name: Song, Baofang
last_name: Song
- first_name: Xingyu
full_name: Ma, Xingyu
id: 34BADBA6-F248-11E8-B48F-1D18A9856A87
last_name: Ma
orcid: 0000-0002-0179-9737
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Xu D, Warnecke S, Song B, Ma X, Hof B. Transition to turbulence in pulsating
pipe flow. Journal of Fluid Mechanics. 2017;831:418-432. doi:10.1017/jfm.2017.620
apa: Xu, D., Warnecke, S., Song, B., Ma, X., & Hof, B. (2017). Transition to
turbulence in pulsating pipe flow. Journal of Fluid Mechanics. Cambridge
University Press. https://doi.org/10.1017/jfm.2017.620
chicago: Xu, Duo, Sascha Warnecke, Baofang Song, Xingyu Ma, and Björn Hof. “Transition
to Turbulence in Pulsating Pipe Flow.” Journal of Fluid Mechanics. Cambridge
University Press, 2017. https://doi.org/10.1017/jfm.2017.620.
ieee: D. Xu, S. Warnecke, B. Song, X. Ma, and B. Hof, “Transition to turbulence
in pulsating pipe flow,” Journal of Fluid Mechanics, vol. 831. Cambridge
University Press, pp. 418–432, 2017.
ista: Xu D, Warnecke S, Song B, Ma X, Hof B. 2017. Transition to turbulence in pulsating
pipe flow. Journal of Fluid Mechanics. 831, 418–432.
mla: Xu, Duo, et al. “Transition to Turbulence in Pulsating Pipe Flow.” Journal
of Fluid Mechanics, vol. 831, Cambridge University Press, 2017, pp. 418–32,
doi:10.1017/jfm.2017.620.
short: D. Xu, S. Warnecke, B. Song, X. Ma, B. Hof, Journal of Fluid Mechanics 831
(2017) 418–432.
date_created: 2018-12-11T11:48:17Z
date_published: 2017-11-25T00:00:00Z
date_updated: 2023-09-27T12:28:12Z
day: '25'
department:
- _id: BjHo
doi: 10.1017/jfm.2017.620
ec_funded: 1
external_id:
isi:
- '000412934800005'
intvolume: ' 831'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1709.03738
month: '11'
oa: 1
oa_version: Submitted Version
page: 418 - 432
project:
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '306589'
name: Decoding the complexity of turbulence at its origin
publication: Journal of Fluid Mechanics
publication_identifier:
issn:
- '00221120'
publication_status: published
publisher: Cambridge University Press
publist_id: '6922'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Transition to turbulence in pulsating pipe flow
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 831
year: '2017'
...
---
_id: '673'
abstract:
- lang: eng
text: We present a numerical study of wavy supercritical cylindrical Couette flow
between counter-rotating cylinders in which the wavy pattern propagates either
prograde with the inner cylinder or retrograde opposite the rotation of the inner
cylinder. The wave propagation reversals from prograde to retrograde and vice
versa occur at distinct values of the inner cylinder Reynolds number when the
associated frequency of the wavy instability vanishes. The reversal occurs for
both twofold and threefold symmetric wavy vortices. Moreover, the wave propagation
reversal only occurs for sufficiently strong counter-rotation. The flow pattern
reversal appears to be intrinsic in the system as either periodic boundary conditions
or fixed end wall boundary conditions for different system sizes always result
in the wave propagation reversal. We present a detailed bifurcation sequence and
parameter space diagram with respect to retrograde behavior of wavy flows. The
retrograde propagation of the instability occurs when the inner Reynolds number
is about two times the outer Reynolds number. The mechanism for the retrograde
propagation is associated with the inviscidly unstable region near the inner cylinder
and the direction of the global average azimuthal velocity. Flow dynamics, spatio-temporal
behavior, global mean angular velocity, and torque of the flow with the wavy pattern
are explored.
article_number: '053103'
article_processing_charge: No
author:
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
- first_name: Richard
full_name: Lueptow, Richard
last_name: Lueptow
citation:
ama: Altmeyer S, Lueptow R. Wave propagation reversal for wavy vortices in wide
gap counter rotating cylindrical Couette flow. Physical Review E. 2017;95(5).
doi:10.1103/PhysRevE.95.053103
apa: Altmeyer, S., & Lueptow, R. (2017). Wave propagation reversal for wavy
vortices in wide gap counter rotating cylindrical Couette flow. Physical Review
E. American Physical Society. https://doi.org/10.1103/PhysRevE.95.053103
chicago: Altmeyer, Sebastian, and Richard Lueptow. “Wave Propagation Reversal for
Wavy Vortices in Wide Gap Counter Rotating Cylindrical Couette Flow.” Physical
Review E. American Physical Society, 2017. https://doi.org/10.1103/PhysRevE.95.053103.
ieee: S. Altmeyer and R. Lueptow, “Wave propagation reversal for wavy vortices in
wide gap counter rotating cylindrical Couette flow,” Physical Review E,
vol. 95, no. 5. American Physical Society, 2017.
ista: Altmeyer S, Lueptow R. 2017. Wave propagation reversal for wavy vortices in
wide gap counter rotating cylindrical Couette flow. Physical Review E. 95(5),
053103.
mla: Altmeyer, Sebastian, and Richard Lueptow. “Wave Propagation Reversal for Wavy
Vortices in Wide Gap Counter Rotating Cylindrical Couette Flow.” Physical Review
E, vol. 95, no. 5, 053103, American Physical Society, 2017, doi:10.1103/PhysRevE.95.053103.
short: S. Altmeyer, R. Lueptow, Physical Review E 95 (2017).
date_created: 2018-12-11T11:47:50Z
date_published: 2017-05-10T00:00:00Z
date_updated: 2023-10-10T13:30:03Z
day: '10'
department:
- _id: BjHo
doi: 10.1103/PhysRevE.95.053103
intvolume: ' 95'
issue: '5'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/pdf/physics/0505164.pdf
month: '05'
oa: 1
oa_version: Submitted Version
publication: Physical Review E
publication_identifier:
issn:
- 2470-0045
publication_status: published
publisher: American Physical Society
publist_id: '7049'
scopus_import: '1'
status: public
title: Wave propagation reversal for wavy vortices in wide gap counter rotating cylindrical
Couette flow
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 95
year: '2017'
...
---
_id: '463'
abstract:
- lang: eng
text: We investigate transient behaviors induced by magnetic fields on the dynamics
of the flow of a ferrofluid in the gap between two concentric, independently rotating
cylinders. Without applying any magnetic fields, we uncover emergence of flow
states constituted by a combination of a localized spiral state (SPIl) in the
top and bottom of the annulus and different multi-cell flow states (SPI2v, SPI3v)
with toroidally closed vortices in the interior of the bulk (SPIl+2v = SPIl +
SPI2v and SPIl+3v = SPIl + SPI3v). However, when a magnetic field is presented,
we observe the transient behaviors between multi-cell states passing through two
critical thresholds in a strength of an axial (transverse) magnetic field. Before
the first critical threshold of a magnetic field strength, multi-stable states
with different number of cells could be observed. After the first critical threshold,
we find the transient behavior between the three- and two-cell flow states. For
more strength of magnetic field or after the second critical threshold, we discover
that multi-cell states are disappeared and a localized spiral state remains to
be stimulated. The studied transient behavior could be understood by the investigation
of various quantities including a modal kinetic energy, a mode amplitude of the
radial velocity, wavenumber, angular momentum, and torque. In addition, the emergence
of new flow states and the transient behavior between their states in ferrofluidic
flows indicate that richer and potentially controllable dynamics through magnetic
fields could be possible in ferrofluic flow.
article_number: '113112'
article_processing_charge: No
article_type: original
author:
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
- first_name: Younghae
full_name: Do, Younghae
last_name: Do
- first_name: Soorok
full_name: Ryu, Soorok
last_name: Ryu
citation:
ama: Altmeyer S, Do Y, Ryu S. Transient behavior between multi-cell flow states
in ferrofluidic Taylor-Couette flow. Chaos. 2017;27(11). doi:10.1063/1.5002771
apa: Altmeyer, S., Do, Y., & Ryu, S. (2017). Transient behavior between multi-cell
flow states in ferrofluidic Taylor-Couette flow. Chaos. AIP Publishing.
https://doi.org/10.1063/1.5002771
chicago: Altmeyer, Sebastian, Younghae Do, and Soorok Ryu. “Transient Behavior between
Multi-Cell Flow States in Ferrofluidic Taylor-Couette Flow.” Chaos. AIP
Publishing, 2017. https://doi.org/10.1063/1.5002771.
ieee: S. Altmeyer, Y. Do, and S. Ryu, “Transient behavior between multi-cell flow
states in ferrofluidic Taylor-Couette flow,” Chaos, vol. 27, no. 11. AIP
Publishing, 2017.
ista: Altmeyer S, Do Y, Ryu S. 2017. Transient behavior between multi-cell flow
states in ferrofluidic Taylor-Couette flow. Chaos. 27(11), 113112.
mla: Altmeyer, Sebastian, et al. “Transient Behavior between Multi-Cell Flow States
in Ferrofluidic Taylor-Couette Flow.” Chaos, vol. 27, no. 11, 113112, AIP
Publishing, 2017, doi:10.1063/1.5002771.
short: S. Altmeyer, Y. Do, S. Ryu, Chaos 27 (2017).
date_created: 2018-12-11T11:46:37Z
date_published: 2017-11-01T00:00:00Z
date_updated: 2024-02-28T13:02:12Z
day: '01'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.1063/1.5002771
file:
- access_level: open_access
checksum: 0731f9d416760c1062db258ca51f8bdc
content_type: application/pdf
creator: dernst
date_created: 2019-10-24T15:14:30Z
date_updated: 2020-07-14T12:46:32Z
file_id: '6970'
file_name: 2017_Chaos_Altmeyer.pdf
file_size: 7714020
relation: main_file
file_date_updated: 2020-07-14T12:46:32Z
has_accepted_license: '1'
intvolume: ' 27'
issue: '11'
language:
- iso: eng
month: '11'
oa: 1
oa_version: Published Version
publication: Chaos
publication_identifier:
issn:
- '10541500'
publication_status: published
publisher: AIP Publishing
publist_id: '7358'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Transient behavior between multi-cell flow states in ferrofluidic Taylor-Couette
flow
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 27
year: '2017'
...
---
_id: '661'
abstract:
- lang: eng
text: During embryonic development, mechanical forces are essential for cellular
rearrangements driving tissue morphogenesis. Here, we show that in the early zebrafish
embryo, friction forces are generated at the interface between anterior axial
mesoderm (prechordal plate, ppl) progenitors migrating towards the animal pole
and neurectoderm progenitors moving in the opposite direction towards the vegetal
pole of the embryo. These friction forces lead to global rearrangement of cells
within the neurectoderm and determine the position of the neural anlage. Using
a combination of experiments and simulations, we show that this process depends
on hydrodynamic coupling between neurectoderm and ppl as a result of E-cadherin-mediated
adhesion between those tissues. Our data thus establish the emergence of friction
forces at the interface between moving tissues as a critical force-generating
process shaping the embryo.
acknowledged_ssus:
- _id: SSU
author:
- first_name: Michael
full_name: Smutny, Michael
id: 3FE6E4E8-F248-11E8-B48F-1D18A9856A87
last_name: Smutny
orcid: 0000-0002-5920-9090
- first_name: Zsuzsa
full_name: Ákos, Zsuzsa
last_name: Ákos
- first_name: Silvia
full_name: Grigolon, Silvia
last_name: Grigolon
- first_name: Shayan
full_name: Shamipour, Shayan
id: 40B34FE2-F248-11E8-B48F-1D18A9856A87
last_name: Shamipour
- first_name: Verena
full_name: Ruprecht, Verena
last_name: Ruprecht
- first_name: Daniel
full_name: Capek, Daniel
id: 31C42484-F248-11E8-B48F-1D18A9856A87
last_name: Capek
orcid: 0000-0001-5199-9940
- first_name: Martin
full_name: Behrndt, Martin
id: 3ECECA3A-F248-11E8-B48F-1D18A9856A87
last_name: Behrndt
- first_name: Ekaterina
full_name: Papusheva, Ekaterina
id: 41DB591E-F248-11E8-B48F-1D18A9856A87
last_name: Papusheva
- first_name: Masazumi
full_name: Tada, Masazumi
last_name: Tada
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
- first_name: Tamás
full_name: Vicsek, Tamás
last_name: Vicsek
- first_name: Guillaume
full_name: Salbreux, Guillaume
last_name: Salbreux
- first_name: Carl-Philipp J
full_name: Heisenberg, Carl-Philipp J
id: 39427864-F248-11E8-B48F-1D18A9856A87
last_name: Heisenberg
orcid: 0000-0002-0912-4566
citation:
ama: Smutny M, Ákos Z, Grigolon S, et al. Friction forces position the neural anlage.
Nature Cell Biology. 2017;19:306-317. doi:10.1038/ncb3492
apa: Smutny, M., Ákos, Z., Grigolon, S., Shamipour, S., Ruprecht, V., Capek, D.,
… Heisenberg, C.-P. J. (2017). Friction forces position the neural anlage. Nature
Cell Biology. Nature Publishing Group. https://doi.org/10.1038/ncb3492
chicago: Smutny, Michael, Zsuzsa Ákos, Silvia Grigolon, Shayan Shamipour, Verena
Ruprecht, Daniel Capek, Martin Behrndt, et al. “Friction Forces Position the Neural
Anlage.” Nature Cell Biology. Nature Publishing Group, 2017. https://doi.org/10.1038/ncb3492.
ieee: M. Smutny et al., “Friction forces position the neural anlage,” Nature
Cell Biology, vol. 19. Nature Publishing Group, pp. 306–317, 2017.
ista: Smutny M, Ákos Z, Grigolon S, Shamipour S, Ruprecht V, Capek D, Behrndt M,
Papusheva E, Tada M, Hof B, Vicsek T, Salbreux G, Heisenberg C-PJ. 2017. Friction
forces position the neural anlage. Nature Cell Biology. 19, 306–317.
mla: Smutny, Michael, et al. “Friction Forces Position the Neural Anlage.” Nature
Cell Biology, vol. 19, Nature Publishing Group, 2017, pp. 306–17, doi:10.1038/ncb3492.
short: M. Smutny, Z. Ákos, S. Grigolon, S. Shamipour, V. Ruprecht, D. Capek, M.
Behrndt, E. Papusheva, M. Tada, B. Hof, T. Vicsek, G. Salbreux, C.-P.J. Heisenberg,
Nature Cell Biology 19 (2017) 306–317.
date_created: 2018-12-11T11:47:46Z
date_published: 2017-03-27T00:00:00Z
date_updated: 2024-03-27T23:30:38Z
day: '27'
department:
- _id: CaHe
- _id: BjHo
- _id: Bio
doi: 10.1038/ncb3492
ec_funded: 1
external_id:
pmid:
- '28346437'
intvolume: ' 19'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://europepmc.org/articles/pmc5635970
month: '03'
oa: 1
oa_version: Submitted Version
page: 306 - 317
pmid: 1
project:
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '306589'
name: Decoding the complexity of turbulence at its origin
- _id: 252ABD0A-B435-11E9-9278-68D0E5697425
call_identifier: FWF
grant_number: I 930-B20
name: Control of Epithelial Cell Layer Spreading in Zebrafish
publication: Nature Cell Biology
publication_identifier:
issn:
- '14657392'
publication_status: published
publisher: Nature Publishing Group
publist_id: '7074'
quality_controlled: '1'
related_material:
record:
- id: '50'
relation: dissertation_contains
status: public
- id: '8350'
relation: dissertation_contains
status: public
scopus_import: 1
status: public
title: Friction forces position the neural anlage
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 19
year: '2017'
...
---
_id: '1494'
abstract:
- lang: eng
text: Turbulence is one of the most frequently encountered non-equilibrium phenomena
in nature, yet characterizing the transition that gives rise to turbulence in
basic shear flows has remained an elusive task. Although, in recent studies, critical
points marking the onset of sustained turbulence have been determined for several
such flows, the physical nature of the transition could not be fully explained.
In extensive experimental and computational studies we show for the example of
Couette flow that the onset of turbulence is a second-order phase transition and
falls into the directed percolation universality class. Consequently, the complex
laminar–turbulent patterns distinctive for the onset of turbulence in shear flows
result from short-range interactions of turbulent domains and are characterized
by universal critical exponents. More generally, our study demonstrates that even
high-dimensional systems far from equilibrium such as turbulence exhibit universality
at onset and that here the collective dynamics obeys simple rules.
acknowledgement: We thank P. Maier for providing valuable ideas and supporting us
in the technical aspects. Discussions with D. Barkley, Y. Duguet, B. Eckhart, N.
Goldenfeld, P. Manneville and K. Takeuchi are gratefully acknowledged. We acknowledge
the Deutsche Forschungsgemeinschaft (Project No. FOR 1182), and the European Research
Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC
Grant Agreement 306589 for financial support. L.S. and B.H. acknowledge research
funding by Deutsche Forschungsgemeinschaft (DFG) under Grant No. SFB 963/1 (project
A8). Numerical simulations were performed thanks to the CPU time allocations of
JUROPA in Juelich Supercomputing Center (project HGU17) and of the Max Planck Computing
and Data Facility (Garching, Germany). Excellent technical support from M. Rampp
on the hybrid code nsCouette is appreciated.
author:
- first_name: Grégoire M
full_name: Lemoult, Grégoire M
id: 4787FE80-F248-11E8-B48F-1D18A9856A87
last_name: Lemoult
- first_name: Liang
full_name: Shi, Liang
id: 374A3F1A-F248-11E8-B48F-1D18A9856A87
last_name: Shi
- first_name: Kerstin
full_name: Avila, Kerstin
last_name: Avila
- first_name: Shreyas V
full_name: Jalikop, Shreyas V
id: 44A1D772-F248-11E8-B48F-1D18A9856A87
last_name: Jalikop
- first_name: Marc
full_name: Avila, Marc
last_name: Avila
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Lemoult GM, Shi L, Avila K, Jalikop SV, Avila M, Hof B. Directed percolation
phase transition to sustained turbulence in Couette flow. Nature Physics.
2016;12(3):254-258. doi:10.1038/nphys3675
apa: Lemoult, G. M., Shi, L., Avila, K., Jalikop, S. V., Avila, M., & Hof, B.
(2016). Directed percolation phase transition to sustained turbulence in Couette
flow. Nature Physics. Nature Publishing Group. https://doi.org/10.1038/nphys3675
chicago: Lemoult, Grégoire M, Liang Shi, Kerstin Avila, Shreyas V Jalikop, Marc
Avila, and Björn Hof. “Directed Percolation Phase Transition to Sustained Turbulence
in Couette Flow.” Nature Physics. Nature Publishing Group, 2016. https://doi.org/10.1038/nphys3675.
ieee: G. M. Lemoult, L. Shi, K. Avila, S. V. Jalikop, M. Avila, and B. Hof, “Directed
percolation phase transition to sustained turbulence in Couette flow,” Nature
Physics, vol. 12, no. 3. Nature Publishing Group, pp. 254–258, 2016.
ista: Lemoult GM, Shi L, Avila K, Jalikop SV, Avila M, Hof B. 2016. Directed percolation
phase transition to sustained turbulence in Couette flow. Nature Physics. 12(3),
254–258.
mla: Lemoult, Grégoire M., et al. “Directed Percolation Phase Transition to Sustained
Turbulence in Couette Flow.” Nature Physics, vol. 12, no. 3, Nature Publishing
Group, 2016, pp. 254–58, doi:10.1038/nphys3675.
short: G.M. Lemoult, L. Shi, K. Avila, S.V. Jalikop, M. Avila, B. Hof, Nature Physics
12 (2016) 254–258.
date_created: 2018-12-11T11:52:21Z
date_published: 2016-02-15T00:00:00Z
date_updated: 2021-01-12T06:51:08Z
day: '15'
department:
- _id: BjHo
doi: 10.1038/nphys3675
ec_funded: 1
intvolume: ' 12'
issue: '3'
language:
- iso: eng
month: '02'
oa_version: None
page: 254 - 258
project:
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '306589'
name: Decoding the complexity of turbulence at its origin
- _id: 2511D90C-B435-11E9-9278-68D0E5697425
grant_number: SFB 963 TP A8
name: Astrophysical instability of currents and turbulences
publication: Nature Physics
publication_status: published
publisher: Nature Publishing Group
publist_id: '5685'
quality_controlled: '1'
scopus_import: 1
status: public
title: Directed percolation phase transition to sustained turbulence in Couette flow
type: journal_article
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 12
year: '2016'
...
---
_id: '1589'
abstract:
- lang: eng
text: We investigate the dynamics of ferrofluidic wavy vortex flows in the counter-rotating
Taylor-Couette system, with a focus on wavy flows with a mixture of the dominant
azimuthal modes. Without external magnetic field flows are stable and pro-grade
with respect to the rotation of the inner cylinder. More complex behaviors can
arise when an axial or a transverse magnetic field is applied. Depending on the
direction and strength of the field, multi-stable wavy states and bifurcations
can occur. We uncover the phenomenon of flow pattern reversal as the strength
of the magnetic field is increased through a critical value. In between the regimes
of pro-grade and retrograde flow rotations, standing waves with zero angular velocities
can emerge. A striking finding is that, under a transverse magnetic field, a second
reversal in the flow pattern direction can occur, where the flow pattern evolves
into pro-grade rotation again from a retrograde state. Flow reversal is relevant
to intriguing phenomena in nature such as geomagnetic reversal. Our results suggest
that, in ferrofluids, flow pattern reversal can be induced by varying a magnetic
field in a controlled manner, which can be realized in laboratory experiments
with potential applications in the development of modern fluid devices.
article_number: '18589'
article_type: original
author:
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
- first_name: Younghae
full_name: Do, Younghae
last_name: Do
- first_name: Ying
full_name: Lai, Ying
last_name: Lai
citation:
ama: Altmeyer S, Do Y, Lai Y. Magnetic field induced flow pattern reversal in a
ferrofluidic Taylor-Couette system. Scientific Reports. 2015;5. doi:10.1038/srep18589
apa: Altmeyer, S., Do, Y., & Lai, Y. (2015). Magnetic field induced flow pattern
reversal in a ferrofluidic Taylor-Couette system. Scientific Reports. Nature
Publishing Group. https://doi.org/10.1038/srep18589
chicago: Altmeyer, Sebastian, Younghae Do, and Ying Lai. “Magnetic Field Induced
Flow Pattern Reversal in a Ferrofluidic Taylor-Couette System.” Scientific
Reports. Nature Publishing Group, 2015. https://doi.org/10.1038/srep18589.
ieee: S. Altmeyer, Y. Do, and Y. Lai, “Magnetic field induced flow pattern reversal
in a ferrofluidic Taylor-Couette system,” Scientific Reports, vol. 5. Nature
Publishing Group, 2015.
ista: Altmeyer S, Do Y, Lai Y. 2015. Magnetic field induced flow pattern reversal
in a ferrofluidic Taylor-Couette system. Scientific Reports. 5, 18589.
mla: Altmeyer, Sebastian, et al. “Magnetic Field Induced Flow Pattern Reversal in
a Ferrofluidic Taylor-Couette System.” Scientific Reports, vol. 5, 18589,
Nature Publishing Group, 2015, doi:10.1038/srep18589.
short: S. Altmeyer, Y. Do, Y. Lai, Scientific Reports 5 (2015).
date_created: 2018-12-11T11:52:53Z
date_published: 2015-12-21T00:00:00Z
date_updated: 2021-01-12T06:51:48Z
day: '21'
ddc:
- '530'
- '540'
department:
- _id: BjHo
doi: 10.1038/srep18589
file:
- access_level: open_access
checksum: 927e151674347661ce36eae2818dafdc
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:13:49Z
date_updated: 2020-07-14T12:45:03Z
file_id: '5036'
file_name: IST-2016-472-v1+1_srep18589.pdf
file_size: 2771236
relation: main_file
file_date_updated: 2020-07-14T12:45:03Z
has_accepted_license: '1'
intvolume: ' 5'
language:
- iso: eng
month: '12'
oa: 1
oa_version: Published Version
publication: Scientific Reports
publication_status: published
publisher: Nature Publishing Group
publist_id: '5582'
pubrep_id: '472'
quality_controlled: '1'
scopus_import: 1
status: public
title: Magnetic field induced flow pattern reversal in a ferrofluidic Taylor-Couette
system
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 5
year: '2015'
...
---
_id: '1588'
abstract:
- lang: eng
text: 'We investigate the Taylor-Couette system where the radius ratio is close
to unity. Systematically increasing the Reynolds number, we observe a number of
previously known transitions, such as one from the classical Taylor vortex flow
(TVF) to wavy vortex flow (WVF) and the transition to fully developed turbulence.
Prior to the onset of turbulence, we observe intermittent bursting patterns of
localized turbulent patches, confirming the experimentally observed pattern of
very short wavelength bursts (VSWBs). A striking finding is that, for a Reynolds
number larger than that for the onset of VSWBs, a new type of intermittently bursting
behavior emerges: patterns of azimuthally closed rings of various orders. We call
them ring-bursting patterns, which surround the cylinder completely but remain
localized and separated in the axial direction through nonturbulent wavy structures.
We employ a number of quantitative measures including the cross-flow energy to
characterize the ring-bursting patterns and to distinguish them from the background
flow. These patterns are interesting because they do not occur in the wide-gap
Taylor-Couette flow systems. The narrow-gap regime is less studied but certainly
deserves further attention to gain deeper insights into complex flow dynamics
in fluids.'
article_number: '053018'
author:
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
- first_name: Younghae
full_name: Do, Younghae
last_name: Do
- first_name: Ying
full_name: Lai, Ying
last_name: Lai
citation:
ama: Altmeyer S, Do Y, Lai Y. Ring-bursting behavior en route to turbulence in narrow-gap
Taylor-Couette flows. Physical Review E. 2015;92(5). doi:10.1103/PhysRevE.92.053018
apa: Altmeyer, S., Do, Y., & Lai, Y. (2015). Ring-bursting behavior en route
to turbulence in narrow-gap Taylor-Couette flows. Physical Review E. American
Physical Society. https://doi.org/10.1103/PhysRevE.92.053018
chicago: Altmeyer, Sebastian, Younghae Do, and Ying Lai. “Ring-Bursting Behavior
En Route to Turbulence in Narrow-Gap Taylor-Couette Flows.” Physical Review
E. American Physical Society, 2015. https://doi.org/10.1103/PhysRevE.92.053018.
ieee: S. Altmeyer, Y. Do, and Y. Lai, “Ring-bursting behavior en route to turbulence
in narrow-gap Taylor-Couette flows,” Physical Review E, vol. 92, no. 5.
American Physical Society, 2015.
ista: Altmeyer S, Do Y, Lai Y. 2015. Ring-bursting behavior en route to turbulence
in narrow-gap Taylor-Couette flows. Physical Review E. 92(5), 053018.
mla: Altmeyer, Sebastian, et al. “Ring-Bursting Behavior En Route to Turbulence
in Narrow-Gap Taylor-Couette Flows.” Physical Review E, vol. 92, no. 5,
053018, American Physical Society, 2015, doi:10.1103/PhysRevE.92.053018.
short: S. Altmeyer, Y. Do, Y. Lai, Physical Review E 92 (2015).
date_created: 2018-12-11T11:52:53Z
date_published: 2015-11-24T00:00:00Z
date_updated: 2021-01-12T06:51:47Z
day: '24'
department:
- _id: BjHo
doi: 10.1103/PhysRevE.92.053018
intvolume: ' 92'
issue: '5'
language:
- iso: eng
month: '11'
oa_version: None
publication: Physical Review E
publication_status: published
publisher: American Physical Society
publist_id: '5583'
quality_controlled: '1'
scopus_import: 1
status: public
title: Ring-bursting behavior en route to turbulence in narrow-gap Taylor-Couette
flows
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 92
year: '2015'
...
---
_id: '1664'
abstract:
- lang: eng
text: Over a century of research into the origin of turbulence in wall-bounded shear
flows has resulted in a puzzling picture in which turbulence appears in a variety
of different states competing with laminar background flow. At moderate flow speeds,
turbulence is confined to localized patches; it is only at higher speeds that
the entire flow becomes turbulent. The origin of the different states encountered
during this transition, the front dynamics of the turbulent regions and the transformation
to full turbulence have yet to be explained. By combining experiments, theory
and computer simulations, here we uncover a bifurcation scenario that explains
the transformation to fully turbulent pipe flow and describe the front dynamics
of the different states encountered in the process. Key to resolving this problem
is the interpretation of the flow as a bistable system with nonlinear propagation
(advection) of turbulent fronts. These findings bridge the gap between our understanding
of the onset of turbulence and fully turbulent flows.
acknowledgement: We acknowledge the Deutsche Forschungsgemeinschaft (Project No. FOR
1182), and the European Research Council under the European Union’s Seventh Framework
Programme (FP/2007-2013)/ERC Grant Agreement 306589 for financial support. B.S.
acknowledges financial support from the Chinese State Scholarship Fund under grant
number 2010629145. B.S. acknowledges support from the International Max Planck Research
School for the Physics of Biological and Complex Systems and the Göttingen Graduate
School for Neurosciences and Molecular Biosciences. We acknowledge computing resources
from GWDG (Gesellschaft für wissenschaftliche Datenverarbeitung Göttingen) and the
Jülich Supercomputing Centre (grant HGU16) where the simulations were performed.
author:
- first_name: Dwight
full_name: Barkley, Dwight
last_name: Barkley
- first_name: Baofang
full_name: Song, Baofang
last_name: Song
- first_name: Mukund
full_name: Vasudevan, Mukund
id: 3C5A959A-F248-11E8-B48F-1D18A9856A87
last_name: Vasudevan
- first_name: Grégoire M
full_name: Lemoult, Grégoire M
id: 4787FE80-F248-11E8-B48F-1D18A9856A87
last_name: Lemoult
- first_name: Marc
full_name: Avila, Marc
last_name: Avila
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Barkley D, Song B, Vasudevan M, Lemoult GM, Avila M, Hof B. The rise of fully
turbulent flow. Nature. 2015;526(7574):550-553. doi:10.1038/nature15701
apa: Barkley, D., Song, B., Vasudevan, M., Lemoult, G. M., Avila, M., & Hof,
B. (2015). The rise of fully turbulent flow. Nature. Nature Publishing
Group. https://doi.org/10.1038/nature15701
chicago: Barkley, Dwight, Baofang Song, Mukund Vasudevan, Grégoire M Lemoult, Marc
Avila, and Björn Hof. “The Rise of Fully Turbulent Flow.” Nature. Nature
Publishing Group, 2015. https://doi.org/10.1038/nature15701.
ieee: D. Barkley, B. Song, M. Vasudevan, G. M. Lemoult, M. Avila, and B. Hof, “The
rise of fully turbulent flow,” Nature, vol. 526, no. 7574. Nature Publishing
Group, pp. 550–553, 2015.
ista: Barkley D, Song B, Vasudevan M, Lemoult GM, Avila M, Hof B. 2015. The rise
of fully turbulent flow. Nature. 526(7574), 550–553.
mla: Barkley, Dwight, et al. “The Rise of Fully Turbulent Flow.” Nature,
vol. 526, no. 7574, Nature Publishing Group, 2015, pp. 550–53, doi:10.1038/nature15701.
short: D. Barkley, B. Song, M. Vasudevan, G.M. Lemoult, M. Avila, B. Hof, Nature
526 (2015) 550–553.
date_created: 2018-12-11T11:53:20Z
date_published: 2015-10-21T00:00:00Z
date_updated: 2021-01-12T06:52:22Z
day: '21'
department:
- _id: BjHo
doi: 10.1038/nature15701
ec_funded: 1
intvolume: ' 526'
issue: '7574'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://arxiv.org/abs/1510.09143
month: '10'
oa: 1
oa_version: Preprint
page: 550 - 553
project:
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '306589'
name: Decoding the complexity of turbulence at its origin
publication: Nature
publication_status: published
publisher: Nature Publishing Group
publist_id: '5485'
quality_controlled: '1'
scopus_import: 1
status: public
title: The rise of fully turbulent flow
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 526
year: '2015'
...
---
_id: '1679'
article_number: '091102'
author:
- first_name: Grégoire M
full_name: Lemoult, Grégoire M
id: 4787FE80-F248-11E8-B48F-1D18A9856A87
last_name: Lemoult
- first_name: Philipp
full_name: Maier, Philipp
id: 384F7C04-F248-11E8-B48F-1D18A9856A87
last_name: Maier
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Lemoult GM, Maier P, Hof B. Taylor’s Forest. Physics of Fluids. 2015;27(9).
doi:10.1063/1.4930850
apa: Lemoult, G. M., Maier, P., & Hof, B. (2015). Taylor’s Forest. Physics
of Fluids. American Institute of Physics. https://doi.org/10.1063/1.4930850
chicago: Lemoult, Grégoire M, Philipp Maier, and Björn Hof. “Taylor’s Forest.” Physics
of Fluids. American Institute of Physics, 2015. https://doi.org/10.1063/1.4930850.
ieee: G. M. Lemoult, P. Maier, and B. Hof, “Taylor’s Forest,” Physics of Fluids,
vol. 27, no. 9. American Institute of Physics, 2015.
ista: Lemoult GM, Maier P, Hof B. 2015. Taylor’s Forest. Physics of Fluids. 27(9),
091102.
mla: Lemoult, Grégoire M., et al. “Taylor’s Forest.” Physics of Fluids, vol.
27, no. 9, 091102, American Institute of Physics, 2015, doi:10.1063/1.4930850.
short: G.M. Lemoult, P. Maier, B. Hof, Physics of Fluids 27 (2015).
date_created: 2018-12-11T11:53:26Z
date_published: 2015-09-24T00:00:00Z
date_updated: 2021-01-12T06:52:28Z
day: '24'
ddc:
- '532'
department:
- _id: BjHo
doi: 10.1063/1.4930850
file:
- access_level: open_access
checksum: 604bba3c2496aadb3efcff77de01ce6c
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:13:35Z
date_updated: 2020-07-14T12:45:12Z
file_id: '5019'
file_name: IST-2017-748-v1+1_1.4930850.pdf
file_size: 872366
relation: main_file
file_date_updated: 2020-07-14T12:45:12Z
has_accepted_license: '1'
intvolume: ' 27'
issue: '9'
language:
- iso: eng
month: '09'
oa: 1
oa_version: Published Version
publication: Physics of Fluids
publication_status: published
publisher: American Institute of Physics
publist_id: '5469'
pubrep_id: '748'
quality_controlled: '1'
scopus_import: 1
status: public
title: Taylor's Forest
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 27
year: '2015'
...
---
_id: '1804'
abstract:
- lang: eng
text: It is known that in classical fluids turbulence typically occurs at high Reynolds
numbers. But can turbulence occur at low Reynolds numbers? Here we investigate
the transition to turbulence in the classic Taylor-Couette system in which the
rotating fluids are manufactured ferrofluids with magnetized nanoparticles embedded
in liquid carriers. We find that, in the presence of a magnetic field transverse
to the symmetry axis of the system, turbulence can occur at Reynolds numbers that
are at least one order of magnitude smaller than those in conventional fluids.
This is established by extensive computational ferrohydrodynamics through a detailed
investigation of transitions in the flow structure, and characterization of behaviors
of physical quantities such as the energy, the wave number, and the angular momentum
through the bifurcations. A finding is that, as the magnetic field is increased,
onset of turbulence can be determined accurately and reliably. Our results imply
that experimental investigation of turbulence may be feasible by using ferrofluids.
Our study of transition to and evolution of turbulence in the Taylor-Couette ferrofluidic
flow system provides insights into the challenging problem of turbulence control.
article_number: '10781'
author:
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
- first_name: Younghae
full_name: Do, Younghae
last_name: Do
- first_name: Ying
full_name: Lai, Ying
last_name: Lai
citation:
ama: Altmeyer S, Do Y, Lai Y. Transition to turbulence in Taylor-Couette ferrofluidic
flow. Scientific Reports. 2015;5. doi:10.1038/srep10781
apa: Altmeyer, S., Do, Y., & Lai, Y. (2015). Transition to turbulence in Taylor-Couette
ferrofluidic flow. Scientific Reports. Nature Publishing Group. https://doi.org/10.1038/srep10781
chicago: Altmeyer, Sebastian, Younghae Do, and Ying Lai. “Transition to Turbulence
in Taylor-Couette Ferrofluidic Flow.” Scientific Reports. Nature Publishing
Group, 2015. https://doi.org/10.1038/srep10781.
ieee: S. Altmeyer, Y. Do, and Y. Lai, “Transition to turbulence in Taylor-Couette
ferrofluidic flow,” Scientific Reports, vol. 5. Nature Publishing Group,
2015.
ista: Altmeyer S, Do Y, Lai Y. 2015. Transition to turbulence in Taylor-Couette
ferrofluidic flow. Scientific Reports. 5, 10781.
mla: Altmeyer, Sebastian, et al. “Transition to Turbulence in Taylor-Couette Ferrofluidic
Flow.” Scientific Reports, vol. 5, 10781, Nature Publishing Group, 2015,
doi:10.1038/srep10781.
short: S. Altmeyer, Y. Do, Y. Lai, Scientific Reports 5 (2015).
date_created: 2018-12-11T11:54:06Z
date_published: 2015-06-12T00:00:00Z
date_updated: 2021-01-12T06:53:18Z
day: '12'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.1038/srep10781
file:
- access_level: open_access
checksum: 7716f582f8c9d82d8f2bf80bf896b440
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:17:26Z
date_updated: 2020-07-14T12:45:16Z
file_id: '5280'
file_name: IST-2016-450-v1+1_srep10781.pdf
file_size: 2449723
relation: main_file
file_date_updated: 2020-07-14T12:45:16Z
has_accepted_license: '1'
intvolume: ' 5'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
publication: Scientific Reports
publication_status: published
publisher: Nature Publishing Group
publist_id: '5306'
pubrep_id: '450'
quality_controlled: '1'
scopus_import: 1
status: public
title: Transition to turbulence in Taylor-Couette ferrofluidic flow
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 5
year: '2015'
...
---
_id: '1837'
abstract:
- lang: eng
text: 'Transition to turbulence in straight pipes occurs in spite of the linear
stability of the laminar Hagen-Poiseuille flow if both the amplitude of flow perturbations
and the Reynolds number Re exceed a minimum threshold (subcritical transition).
As the pipe curvature increases, centrifugal effects become important, modifying
the basic flow as well as the most unstable linear modes. If the curvature (tube-to-coiling
diameter d/D) is sufficiently large, a Hopf bifurcation (supercritical instability)
is encountered before turbulence can be excited (subcritical instability). We
trace the instability thresholds in the Re - d/D parameter space in the range
0.01 ≤ d/D\ ≤ 0.1 by means of laser-Doppler velocimetry and determine the point
where the subcritical and supercritical instabilities meet. Two different experimental
set-ups are used: a closed system where the pipe forms an axisymmetric torus and
an open system employing a helical pipe. Implications for the measurement of friction
factors in curved pipes are discussed.'
article_number: R3
article_processing_charge: No
article_type: original
author:
- first_name: Jakob
full_name: Kühnen, Jakob
id: 3A47AE32-F248-11E8-B48F-1D18A9856A87
last_name: Kühnen
orcid: 0000-0003-4312-0179
- first_name: P
full_name: Braunshier, P
last_name: Braunshier
- first_name: M
full_name: Schwegel, M
last_name: Schwegel
- first_name: Hendrik
full_name: Kuhlmann, Hendrik
last_name: Kuhlmann
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Kühnen J, Braunshier P, Schwegel M, Kuhlmann H, Hof B. Subcritical versus supercritical
transition to turbulence in curved pipes. Journal of Fluid Mechanics. 2015;770(5).
doi:10.1017/jfm.2015.184
apa: Kühnen, J., Braunshier, P., Schwegel, M., Kuhlmann, H., & Hof, B. (2015).
Subcritical versus supercritical transition to turbulence in curved pipes. Journal
of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2015.184
chicago: Kühnen, Jakob, P Braunshier, M Schwegel, Hendrik Kuhlmann, and Björn Hof.
“Subcritical versus Supercritical Transition to Turbulence in Curved Pipes.” Journal
of Fluid Mechanics. Cambridge University Press, 2015. https://doi.org/10.1017/jfm.2015.184.
ieee: J. Kühnen, P. Braunshier, M. Schwegel, H. Kuhlmann, and B. Hof, “Subcritical
versus supercritical transition to turbulence in curved pipes,” Journal of
Fluid Mechanics, vol. 770, no. 5. Cambridge University Press, 2015.
ista: Kühnen J, Braunshier P, Schwegel M, Kuhlmann H, Hof B. 2015. Subcritical versus
supercritical transition to turbulence in curved pipes. Journal of Fluid Mechanics.
770(5), R3.
mla: Kühnen, Jakob, et al. “Subcritical versus Supercritical Transition to Turbulence
in Curved Pipes.” Journal of Fluid Mechanics, vol. 770, no. 5, R3, Cambridge
University Press, 2015, doi:10.1017/jfm.2015.184.
short: J. Kühnen, P. Braunshier, M. Schwegel, H. Kuhlmann, B. Hof, Journal of Fluid
Mechanics 770 (2015).
date_created: 2018-12-11T11:54:17Z
date_published: 2015-04-08T00:00:00Z
date_updated: 2021-01-12T06:53:31Z
day: '08'
department:
- _id: BjHo
doi: 10.1017/jfm.2015.184
ec_funded: 1
external_id:
arxiv:
- '1508.06559'
intvolume: ' 770'
issue: '5'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1508.06559
month: '04'
oa: 1
oa_version: Preprint
project:
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '306589'
name: Decoding the complexity of turbulence at its origin
publication: Journal of Fluid Mechanics
publication_status: published
publisher: Cambridge University Press
publist_id: '5265'
quality_controlled: '1'
scopus_import: 1
status: public
title: Subcritical versus supercritical transition to turbulence in curved pipes
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 770
year: '2015'
...
---
_id: '1868'
abstract:
- lang: eng
text: We investigate high-dimensional nonlinear dynamical systems exhibiting multiple
resonances under adiabatic parameter variations. Our motivations come from experimental
considerations where time-dependent sweeping of parameters is a practical approach
to probing and characterizing the bifurcations of the system. The question is
whether bifurcations so detected are faithful representations of the bifurcations
intrinsic to the original stationary system. Utilizing a harmonically forced,
closed fluid flow system that possesses multiple resonances and solving the Navier-Stokes
equation under proper boundary conditions, we uncover the phenomenon of the early
effect. Specifically, as a control parameter, e.g., the driving frequency, is
adiabatically increased from an initial value, resonances emerge at frequency
values that are lower than those in the corresponding stationary system. The phenomenon
is established by numerical characterization of physical quantities through the
resonances, which include the kinetic energy and the vorticity field, and a heuristic
analysis based on the concept of instantaneous frequency. A simple formula is
obtained which relates the resonance points in the time-dependent and time-independent
systems. Our findings suggest that, in general, any true bifurcation of a nonlinear
dynamical system can be unequivocally uncovered through adiabatic parameter sweeping,
in spite of a shift in the bifurcation point, which is of value to experimental
studies of nonlinear dynamical systems.
article_number: '022906'
author:
- first_name: Youngyong
full_name: Park, Youngyong
last_name: Park
- first_name: Younghae
full_name: Do, Younghae
last_name: Do
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
- first_name: Yingcheng
full_name: Lai, Yingcheng
last_name: Lai
- first_name: Gyuwon
full_name: Lee, Gyuwon
last_name: Lee
citation:
ama: Park Y, Do Y, Altmeyer S, Lai Y, Lee G. Early effect in time-dependent, high-dimensional
nonlinear dynamical systems with multiple resonances. Physical Review E.
2015;91(2). doi:10.1103/PhysRevE.91.022906
apa: Park, Y., Do, Y., Altmeyer, S., Lai, Y., & Lee, G. (2015). Early effect
in time-dependent, high-dimensional nonlinear dynamical systems with multiple
resonances. Physical Review E. American Physical Society. https://doi.org/10.1103/PhysRevE.91.022906
chicago: Park, Youngyong, Younghae Do, Sebastian Altmeyer, Yingcheng Lai, and Gyuwon
Lee. “Early Effect in Time-Dependent, High-Dimensional Nonlinear Dynamical Systems
with Multiple Resonances.” Physical Review E. American Physical Society,
2015. https://doi.org/10.1103/PhysRevE.91.022906.
ieee: Y. Park, Y. Do, S. Altmeyer, Y. Lai, and G. Lee, “Early effect in time-dependent,
high-dimensional nonlinear dynamical systems with multiple resonances,” Physical
Review E, vol. 91, no. 2. American Physical Society, 2015.
ista: Park Y, Do Y, Altmeyer S, Lai Y, Lee G. 2015. Early effect in time-dependent,
high-dimensional nonlinear dynamical systems with multiple resonances. Physical
Review E. 91(2), 022906.
mla: Park, Youngyong, et al. “Early Effect in Time-Dependent, High-Dimensional Nonlinear
Dynamical Systems with Multiple Resonances.” Physical Review E, vol. 91,
no. 2, 022906, American Physical Society, 2015, doi:10.1103/PhysRevE.91.022906.
short: Y. Park, Y. Do, S. Altmeyer, Y. Lai, G. Lee, Physical Review E 91 (2015).
date_created: 2018-12-11T11:54:27Z
date_published: 2015-02-09T00:00:00Z
date_updated: 2021-01-12T06:53:44Z
day: '09'
department:
- _id: BjHo
doi: 10.1103/PhysRevE.91.022906
intvolume: ' 91'
issue: '2'
language:
- iso: eng
month: '02'
oa_version: None
publication: Physical Review E
publication_identifier:
issn:
- 1539-3755
publication_status: published
publisher: American Physical Society
publist_id: '5229'
quality_controlled: '1'
scopus_import: 1
status: public
title: Early effect in time-dependent, high-dimensional nonlinear dynamical systems
with multiple resonances
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 91
year: '2015'
...
---
_id: '2030'
abstract:
- lang: eng
text: A hybrid-parallel direct-numerical-simulation method with application to turbulent
Taylor-Couette flow is presented. The Navier-Stokes equations are discretized
in cylindrical coordinates with the spectral Fourier-Galerkin method in the axial
and azimuthal directions, and high-order finite differences in the radial direction.
Time is advanced by a second-order, semi-implicit projection scheme, which requires
the solution of five Helmholtz/Poisson equations, avoids staggered grids and renders
very small slip velocities. Nonlinear terms are evaluated with the pseudospectral
method. The code is parallelized using a hybrid MPI-OpenMP strategy, which, compared
with a flat MPI parallelization, is simpler to implement, allows to reduce inter-node
communications and MPI overhead that become relevant at high processor-core counts,
and helps to contain the memory footprint. A strong scaling study shows that the
hybrid code maintains scalability up to more than 20,000 processor cores and thus
allows to perform simulations at higher resolutions than previously feasible.
In particular, it opens up the possibility to simulate turbulent Taylor-Couette
flows at Reynolds numbers up to O(105). This enables to probe hydrodynamic turbulence
in Keplerian flows in experimentally relevant regimes.
author:
- first_name: Liang
full_name: Shi, Liang
id: 374A3F1A-F248-11E8-B48F-1D18A9856A87
last_name: Shi
- first_name: Markus
full_name: Rampp, Markus
last_name: Rampp
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
- first_name: Marc
full_name: Avila, Marc
last_name: Avila
citation:
ama: Shi L, Rampp M, Hof B, Avila M. A hybrid MPI-OpenMP parallel implementation
for pseudospectral simulations with application to Taylor-Couette flow. Computers
and Fluids. 2015;106(1):1-11. doi:10.1016/j.compfluid.2014.09.021
apa: Shi, L., Rampp, M., Hof, B., & Avila, M. (2015). A hybrid MPI-OpenMP parallel
implementation for pseudospectral simulations with application to Taylor-Couette
flow. Computers and Fluids. Elsevier. https://doi.org/10.1016/j.compfluid.2014.09.021
chicago: Shi, Liang, Markus Rampp, Björn Hof, and Marc Avila. “A Hybrid MPI-OpenMP
Parallel Implementation for Pseudospectral Simulations with Application to Taylor-Couette
Flow.” Computers and Fluids. Elsevier, 2015. https://doi.org/10.1016/j.compfluid.2014.09.021.
ieee: L. Shi, M. Rampp, B. Hof, and M. Avila, “A hybrid MPI-OpenMP parallel implementation
for pseudospectral simulations with application to Taylor-Couette flow,” Computers
and Fluids, vol. 106, no. 1. Elsevier, pp. 1–11, 2015.
ista: Shi L, Rampp M, Hof B, Avila M. 2015. A hybrid MPI-OpenMP parallel implementation
for pseudospectral simulations with application to Taylor-Couette flow. Computers
and Fluids. 106(1), 1–11.
mla: Shi, Liang, et al. “A Hybrid MPI-OpenMP Parallel Implementation for Pseudospectral
Simulations with Application to Taylor-Couette Flow.” Computers and Fluids,
vol. 106, no. 1, Elsevier, 2015, pp. 1–11, doi:10.1016/j.compfluid.2014.09.021.
short: L. Shi, M. Rampp, B. Hof, M. Avila, Computers and Fluids 106 (2015) 1–11.
date_created: 2018-12-11T11:55:18Z
date_published: 2015-01-01T00:00:00Z
date_updated: 2021-01-12T06:54:51Z
day: '01'
department:
- _id: BjHo
doi: 10.1016/j.compfluid.2014.09.021
intvolume: ' 106'
issue: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://arxiv.org/abs/1311.2481
month: '01'
oa: 1
oa_version: Preprint
page: 1 - 11
publication: Computers and Fluids
publication_status: published
publisher: Elsevier
publist_id: '5042'
quality_controlled: '1'
scopus_import: 1
status: public
title: A hybrid MPI-OpenMP parallel implementation for pseudospectral simulations
with application to Taylor-Couette flow
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 106
year: '2015'
...
---
_id: '2050'
abstract:
- lang: eng
text: The flow instability and further transition to turbulence in a toroidal pipe
(torus) with curvature ratio (tube-to-coiling diameter) 0.049 is investigated
experimentally. The flow inside the toroidal pipe is driven by a steel sphere
fitted to the inner pipe diameter. The sphere is moved with constant azimuthal
velocity from outside the torus by a moving magnet. The experiment is designed
to investigate curved pipe flow by optical measurement techniques. Using stereoscopic
particle image velocimetry, laser Doppler velocimetry and pressure drop measurements,
the flow is measured for Reynolds numbers ranging from 1000 to 15 000. Time- and
space-resolved velocity fields are obtained and analysed. The steady axisymmetric
basic flow is strongly influenced by centrifugal effects. On an increase of the
Reynolds number we find a sequence of bifurcations. For Re=4075±2% a supercritical
bifurcation to an oscillatory flow is found in which waves travel in the streamwise
direction with a phase velocity slightly faster than the mean flow. The oscillatory
flow is superseded by a presumably quasi-periodic flow at a further increase of
the Reynolds number before turbulence sets in. The results are found to be compatible,
in general, with earlier experimental and numerical investigations on transition
to turbulence in helical and curved pipes. However, important aspects of the bifurcation
scenario differ considerably.
article_processing_charge: No
author:
- first_name: Jakob
full_name: Kühnen, Jakob
id: 3A47AE32-F248-11E8-B48F-1D18A9856A87
last_name: Kühnen
orcid: 0000-0003-4312-0179
- first_name: Markus
full_name: Holzner, Markus
last_name: Holzner
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
- first_name: Hendrik
full_name: Kuhlmann, Hendrik
last_name: Kuhlmann
citation:
ama: Kühnen J, Holzner M, Hof B, Kuhlmann H. Experimental investigation of transitional
flow in a toroidal pipe. Journal of Fluid Mechanics. 2014;738:463-491.
doi:10.1017/jfm.2013.603
apa: Kühnen, J., Holzner, M., Hof, B., & Kuhlmann, H. (2014). Experimental investigation
of transitional flow in a toroidal pipe. Journal of Fluid Mechanics. Cambridge
University Press. https://doi.org/10.1017/jfm.2013.603
chicago: Kühnen, Jakob, Markus Holzner, Björn Hof, and Hendrik Kuhlmann. “Experimental
Investigation of Transitional Flow in a Toroidal Pipe.” Journal of Fluid Mechanics.
Cambridge University Press, 2014. https://doi.org/10.1017/jfm.2013.603.
ieee: J. Kühnen, M. Holzner, B. Hof, and H. Kuhlmann, “Experimental investigation
of transitional flow in a toroidal pipe,” Journal of Fluid Mechanics, vol.
738. Cambridge University Press, pp. 463–491, 2014.
ista: Kühnen J, Holzner M, Hof B, Kuhlmann H. 2014. Experimental investigation of
transitional flow in a toroidal pipe. Journal of Fluid Mechanics. 738, 463–491.
mla: Kühnen, Jakob, et al. “Experimental Investigation of Transitional Flow in a
Toroidal Pipe.” Journal of Fluid Mechanics, vol. 738, Cambridge University
Press, 2014, pp. 463–91, doi:10.1017/jfm.2013.603.
short: J. Kühnen, M. Holzner, B. Hof, H. Kuhlmann, Journal of Fluid Mechanics 738
(2014) 463–491.
date_created: 2018-12-11T11:55:25Z
date_published: 2014-01-10T00:00:00Z
date_updated: 2021-01-12T06:54:59Z
day: '10'
department:
- _id: BjHo
doi: 10.1017/jfm.2013.603
external_id:
arxiv:
- '1508.06546'
intvolume: ' 738'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1508.06546
month: '01'
oa: 1
oa_version: Submitted Version
page: 463 - 491
publication: Journal of Fluid Mechanics
publication_status: published
publisher: Cambridge University Press
publist_id: '5001'
quality_controlled: '1'
scopus_import: 1
status: public
title: Experimental investigation of transitional flow in a toroidal pipe
type: journal_article
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 738
year: '2014'
...
---
_id: '2224'
abstract:
- lang: eng
text: This work investigates the transition between different traveling helical
waves (spirals, SPIs) in the setup of differentially independent rotating cylinders.
We use direct numerical simulations to consider an infinite long and periodic
Taylor-Couette apparatus with fixed axial periodicity length. We find so-called
mixed-cross-spirals (MCSs), that can be seen as nonlinear superpositions of SPIs,
to establish stable footbridges connecting SPI states. While bridging the bifurcation
branches of SPIs, the corresponding contributions within the MCS vary continuously
with the control parameters. Here discussed MCSs presenting footbridge solutions
start and end in different SPI branches. Therefore they differ significantly from
the already known MCSs that present bypass solutions (Altmeyer and Hoffmann 2010
New J. Phys. 12 113035). The latter start and end in the same SPI branch, while
they always bifurcate out of those SPI branches with the larger mode amplitude.
Meanwhile, these only appear within the coexisting region of both SPIs. In contrast,
the footbridge solutions can also bifurcate out of the minor SPI contribution.
We also find they exist in regions where only one of the SPIs contributions exists.
In addition, MCS as footbridge solution can appear either stable or unstable.
The latter detected transient solutions offer similar spatio-temporal characteristics
to the flow establishing stable footbridges. Such transition processes are interesting
for pattern-forming systems in general because they accomplish transitions between
traveling waves of different azimuthal wave numbers and have not been described
in the literature yet.
article_number: '025503'
author:
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
citation:
ama: Altmeyer S. On secondary instabilities generating footbridges between spiral
vortex flow. Fluid Dynamics Research. 2014;46(2). doi:10.1088/0169-5983/46/2/025503
apa: Altmeyer, S. (2014). On secondary instabilities generating footbridges between
spiral vortex flow. Fluid Dynamics Research. IOP Publishing Ltd. https://doi.org/10.1088/0169-5983/46/2/025503
chicago: Altmeyer, Sebastian. “On Secondary Instabilities Generating Footbridges
between Spiral Vortex Flow.” Fluid Dynamics Research. IOP Publishing Ltd.,
2014. https://doi.org/10.1088/0169-5983/46/2/025503.
ieee: S. Altmeyer, “On secondary instabilities generating footbridges between spiral
vortex flow,” Fluid Dynamics Research, vol. 46, no. 2. IOP Publishing Ltd.,
2014.
ista: Altmeyer S. 2014. On secondary instabilities generating footbridges between
spiral vortex flow. Fluid Dynamics Research. 46(2), 025503.
mla: Altmeyer, Sebastian. “On Secondary Instabilities Generating Footbridges between
Spiral Vortex Flow.” Fluid Dynamics Research, vol. 46, no. 2, 025503, IOP
Publishing Ltd., 2014, doi:10.1088/0169-5983/46/2/025503.
short: S. Altmeyer, Fluid Dynamics Research 46 (2014).
date_created: 2018-12-11T11:56:25Z
date_published: 2014-04-01T00:00:00Z
date_updated: 2021-01-12T06:56:07Z
day: '01'
department:
- _id: BjHo
doi: 10.1088/0169-5983/46/2/025503
intvolume: ' 46'
issue: '2'
language:
- iso: eng
month: '04'
oa_version: None
publication: Fluid Dynamics Research
publication_identifier:
issn:
- '01695983'
publication_status: published
publisher: IOP Publishing Ltd.
publist_id: '4740'
quality_controlled: '1'
scopus_import: 1
status: public
title: On secondary instabilities generating footbridges between spiral vortex flow
type: journal_article
user_id: 4435EBFC-F248-11E8-B48F-1D18A9856A87
volume: 46
year: '2014'
...
---
_id: '2232'
abstract:
- lang: eng
text: The purpose of this contribution is to summarize and discuss recent advances
regarding the onset of turbulence in shear flows. The absence of a clear-cut instability
mechanism, the spatio-temporal intermittent character and extremely long lived
transients are some of the major difficulties encountered in these flows and have
hindered progress towards understanding the transition process. We will show for
the case of pipe flow that concepts from nonlinear dynamics and statistical physics
can help to explain the onset of turbulence. In particular, the turbulent structures
(puffs) observed close to onset are spatially localized chaotic transients and
their lifetimes increase super-exponentially with Reynolds number. At the same
time fluctuations of individual turbulent puffs can (although very rarely) lead
to the nucleation of new puffs. The competition between these two stochastic processes
gives rise to a non-equilibrium phase transition where turbulence changes from
a super-transient to a sustained state.
article_number: P02001
article_processing_charge: No
article_type: original
author:
- first_name: Baofang
full_name: Song, Baofang
id: a79e57f5-e8a5-11ec-9dc9-83fb8c81cf72
last_name: Song
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Song B, Hof B. Deterministic and stochastic aspects of the transition to turbulence.
Journal of Statistical Mechanics Theory and Experiment. 2014;2014(2). doi:10.1088/1742-5468/2014/02/P02001
apa: Song, B., & Hof, B. (2014). Deterministic and stochastic aspects of the
transition to turbulence. Journal of Statistical Mechanics Theory and Experiment.
IOP Publishing. https://doi.org/10.1088/1742-5468/2014/02/P02001
chicago: Song, Baofang, and Björn Hof. “Deterministic and Stochastic Aspects of
the Transition to Turbulence.” Journal of Statistical Mechanics Theory and
Experiment. IOP Publishing, 2014. https://doi.org/10.1088/1742-5468/2014/02/P02001.
ieee: B. Song and B. Hof, “Deterministic and stochastic aspects of the transition
to turbulence,” Journal of Statistical Mechanics Theory and Experiment,
vol. 2014, no. 2. IOP Publishing, 2014.
ista: Song B, Hof B. 2014. Deterministic and stochastic aspects of the transition
to turbulence. Journal of Statistical Mechanics Theory and Experiment. 2014(2),
P02001.
mla: Song, Baofang, and Björn Hof. “Deterministic and Stochastic Aspects of the
Transition to Turbulence.” Journal of Statistical Mechanics Theory and Experiment,
vol. 2014, no. 2, P02001, IOP Publishing, 2014, doi:10.1088/1742-5468/2014/02/P02001.
short: B. Song, B. Hof, Journal of Statistical Mechanics Theory and Experiment 2014
(2014).
date_created: 2018-12-11T11:56:28Z
date_published: 2014-02-01T00:00:00Z
date_updated: 2022-06-10T10:13:15Z
day: '01'
department:
- _id: BjHo
doi: 10.1088/1742-5468/2014/02/P02001
external_id:
arxiv:
- '1403.4516'
intvolume: ' 2014'
issue: '2'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://arxiv.org/abs/1403.4516
month: '02'
oa: 1
oa_version: Submitted Version
publication: Journal of Statistical Mechanics Theory and Experiment
publication_identifier:
issn:
- '17425468'
publication_status: published
publisher: IOP Publishing
publist_id: '4729'
quality_controlled: '1'
status: public
title: Deterministic and stochastic aspects of the transition to turbulence
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 2014
year: '2014'
...
---
_id: '2226'
abstract:
- lang: eng
text: Coriolis force effects on shear flows are important in geophysical and astrophysical
contexts. We report a study on the linear stability and the transient energy growth
of the plane Couette flow with system rotation perpendicular to the shear direction.
External rotation causes linear instability. At small rotation rates, the onset
of linear instability scales inversely with the rotation rate and the optimal
transient growth in the linearly stable region is slightly enhanced ∼Re2. The
corresponding optimal initial perturbations are characterized by roll structures
inclined in the streamwise direction and are twisted under external rotation.
At large rotation rates, the transient growth is significantly inhibited and hence
linear stability analysis is a reliable indicator for instability.
article_number: '013001'
author:
- first_name: Liang
full_name: Shi, Liang
last_name: Shi
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
- first_name: Andreas
full_name: Tilgner, Andreas
last_name: Tilgner
citation:
ama: Shi L, Hof B, Tilgner A. Transient growth of Ekman-Couette flow. Physical
Review E Statistical Nonlinear and Soft Matter Physics. 2014;89(1). doi:10.1103/PhysRevE.89.013001
apa: Shi, L., Hof, B., & Tilgner, A. (2014). Transient growth of Ekman-Couette
flow. Physical Review E Statistical Nonlinear and Soft Matter Physics.
American Institute of Physics. https://doi.org/10.1103/PhysRevE.89.013001
chicago: Shi, Liang, Björn Hof, and Andreas Tilgner. “Transient Growth of Ekman-Couette
Flow.” Physical Review E Statistical Nonlinear and Soft Matter Physics.
American Institute of Physics, 2014. https://doi.org/10.1103/PhysRevE.89.013001.
ieee: L. Shi, B. Hof, and A. Tilgner, “Transient growth of Ekman-Couette flow,”
Physical Review E Statistical Nonlinear and Soft Matter Physics, vol. 89,
no. 1. American Institute of Physics, 2014.
ista: Shi L, Hof B, Tilgner A. 2014. Transient growth of Ekman-Couette flow. Physical
Review E Statistical Nonlinear and Soft Matter Physics. 89(1), 013001.
mla: Shi, Liang, et al. “Transient Growth of Ekman-Couette Flow.” Physical Review
E Statistical Nonlinear and Soft Matter Physics, vol. 89, no. 1, 013001, American
Institute of Physics, 2014, doi:10.1103/PhysRevE.89.013001.
short: L. Shi, B. Hof, A. Tilgner, Physical Review E Statistical Nonlinear and Soft
Matter Physics 89 (2014).
date_created: 2018-12-11T11:56:26Z
date_published: 2014-01-06T00:00:00Z
date_updated: 2021-01-12T06:56:08Z
day: '06'
department:
- _id: BjHo
doi: 10.1103/PhysRevE.89.013001
intvolume: ' 89'
issue: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://arxiv.org/abs/1312.5095
month: '01'
oa: 1
oa_version: Submitted Version
project:
- _id: 25BDE9A4-B435-11E9-9278-68D0E5697425
grant_number: SFB-TR3-TP10B
name: Glutamaterge synaptische Übertragung und Plastizität in hippocampalen Mikroschaltkreisen
publication: Physical Review E Statistical Nonlinear and Soft Matter Physics
publication_identifier:
issn:
- '15393755'
publication_status: published
publisher: American Institute of Physics
publist_id: '4737'
quality_controlled: '1'
scopus_import: 1
status: public
title: Transient growth of Ekman-Couette flow
type: journal_article
user_id: 4435EBFC-F248-11E8-B48F-1D18A9856A87
volume: 89
year: '2014'
...
---
_id: '2806'
abstract:
- lang: eng
text: A novel Taylor-Couette system has been constructed for investigations of transitional
as well as high Reynolds number turbulent flows in very large aspect ratios. The
flexibility of the setup enables studies of a variety of problems regarding hydrodynamic
instabilities and turbulence in rotating flows. The inner and outer cylinders
and the top and bottom endplates can be rotated independently with rotation rates
of up to 30 Hz, thereby covering five orders of magnitude in Reynolds numbers
(Re = 101-106). The radius ratio can be easily changed, the highest realized one
is η = 0.98 corresponding to an aspect ratio of 260 gap width in the vertical
and 300 in the azimuthal direction. For η < 0.98 the aspect ratio can be dynamically
changed during measurements and complete transparency in the radial direction
over the full length of the cylinders is provided by the usage of a precision
glass inner cylinder. The temperatures of both cylinders are controlled independently.
Overall this apparatus combines an unmatched variety in geometry, rotation rates,
and temperatures, which is provided by a sophisticated high-precision bearing
system. Possible applications are accurate studies of the onset of turbulence
and spatio-temporal intermittent flow patterns in very large domains, transport
processes of turbulence at high Re, the stability of Keplerian flows for different
boundary conditions, and studies of baroclinic instabilities.
article_number: '065106'
author:
- first_name: Kerstin
full_name: Avila, Kerstin
last_name: Avila
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Avila K, Hof B. High-precision Taylor-Couette experiment to study subcritical
transitions and the role of boundary conditions and size effects. Review of
Scientific Instruments. 2013;84(6). doi:10.1063/1.4807704
apa: Avila, K., & Hof, B. (2013). High-precision Taylor-Couette experiment to
study subcritical transitions and the role of boundary conditions and size effects.
Review of Scientific Instruments. American Institute of Physics. https://doi.org/10.1063/1.4807704
chicago: Avila, Kerstin, and Björn Hof. “High-Precision Taylor-Couette Experiment
to Study Subcritical Transitions and the Role of Boundary Conditions and Size
Effects.” Review of Scientific Instruments. American Institute of Physics,
2013. https://doi.org/10.1063/1.4807704.
ieee: K. Avila and B. Hof, “High-precision Taylor-Couette experiment to study subcritical
transitions and the role of boundary conditions and size effects,” Review of
Scientific Instruments, vol. 84, no. 6. American Institute of Physics, 2013.
ista: Avila K, Hof B. 2013. High-precision Taylor-Couette experiment to study subcritical
transitions and the role of boundary conditions and size effects. Review of Scientific
Instruments. 84(6), 065106.
mla: Avila, Kerstin, and Björn Hof. “High-Precision Taylor-Couette Experiment to
Study Subcritical Transitions and the Role of Boundary Conditions and Size Effects.”
Review of Scientific Instruments, vol. 84, no. 6, 065106, American Institute
of Physics, 2013, doi:10.1063/1.4807704.
short: K. Avila, B. Hof, Review of Scientific Instruments 84 (2013).
date_created: 2018-12-11T11:59:42Z
date_published: 2013-06-06T00:00:00Z
date_updated: 2021-01-12T06:59:50Z
day: '06'
department:
- _id: BjHo
doi: 10.1063/1.4807704
intvolume: ' 84'
issue: '6'
language:
- iso: eng
month: '06'
oa_version: None
publication: Review of Scientific Instruments
publication_status: published
publisher: American Institute of Physics
publist_id: '4081'
quality_controlled: '1'
scopus_import: 1
status: public
title: High-precision Taylor-Couette experiment to study subcritical transitions and
the role of boundary conditions and size effects
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 84
year: '2013'
...
---
_id: '2811'
abstract:
- lang: eng
text: 'In pipe, channel, and boundary layer flows turbulence first occurs intermittently
in space and time: at moderate Reynolds numbers domains of disordered turbulent
motion are separated by quiescent laminar regions. Based on direct numerical simulations
of pipe flow we argue here that the spatial intermittency has its origin in a
nearest neighbor interaction between turbulent regions. We further show that in
this regime turbulent flows are intrinsically intermittent with a well-defined
equilibrium turbulent fraction but without ever assuming a steady pattern. This
transition scenario is analogous to that found in simple models such as coupled
map lattices. The scaling observed implies that laminar intermissions of the turbulent
flow will persist to arbitrarily large Reynolds numbers.'
article_number: '063012'
author:
- first_name: Marc
full_name: Avila, Marc
last_name: Avila
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Avila M, Hof B. Nature of laminar-turbulence intermittency in shear flows.
Physical Review E. 2013;87(6). doi:10.1103/PhysRevE.87.063012
apa: Avila, M., & Hof, B. (2013). Nature of laminar-turbulence intermittency
in shear flows. Physical Review E. American Institute of Physics. https://doi.org/10.1103/PhysRevE.87.063012
chicago: Avila, Marc, and Björn Hof. “Nature of Laminar-Turbulence Intermittency
in Shear Flows.” Physical Review E. American Institute of Physics, 2013.
https://doi.org/10.1103/PhysRevE.87.063012.
ieee: M. Avila and B. Hof, “Nature of laminar-turbulence intermittency in shear
flows,” Physical Review E, vol. 87, no. 6. American Institute of Physics,
2013.
ista: Avila M, Hof B. 2013. Nature of laminar-turbulence intermittency in shear
flows. Physical Review E. 87(6), 063012.
mla: Avila, Marc, and Björn Hof. “Nature of Laminar-Turbulence Intermittency in
Shear Flows.” Physical Review E, vol. 87, no. 6, 063012, American Institute
of Physics, 2013, doi:10.1103/PhysRevE.87.063012.
short: M. Avila, B. Hof, Physical Review E 87 (2013).
date_created: 2018-12-11T11:59:43Z
date_published: 2013-06-18T00:00:00Z
date_updated: 2021-01-12T06:59:53Z
day: '18'
department:
- _id: BjHo
doi: 10.1103/PhysRevE.87.063012
ec_funded: 1
external_id:
arxiv:
- '1306.5890'
intvolume: ' 87'
issue: '6'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://arxiv.org/abs/1306.5890
month: '06'
oa: 1
oa_version: Preprint
project:
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '306589'
name: Decoding the complexity of turbulence at its origin
publication: Physical Review E
publication_status: published
publisher: American Institute of Physics
publist_id: '4074'
quality_controlled: '1'
scopus_import: 1
status: public
title: Nature of laminar-turbulence intermittency in shear flows
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 87
year: '2013'
...
---
_id: '2813'
abstract:
- lang: eng
text: Turbulence is ubiquitous in nature, yet even for the case of ordinary Newtonian
fluids like water, our understanding of this phenomenon is limited. Many liquids
of practical importance are more complicated (e.g., blood, polymer melts, paints),
however; they exhibit elastic as well as viscous characteristics, and the relation
between stress and strain is nonlinear. We demonstrate here for a model system
of such complex fluids that at high shear rates, turbulence is not simply modified
as previously believed but is suppressed and replaced by a different type of disordered
motion, elasto-inertial turbulence. Elasto-inertial turbulence is found to occur
at much lower Reynolds numbers than Newtonian turbulence, and the dynamical properties
differ significantly. The friction scaling observed coincides with the so-called
"maximum drag reduction" asymptote, which is exhibited by a wide range
of viscoelastic fluids.
author:
- first_name: Devranjan
full_name: Samanta, Devranjan
last_name: Samanta
- first_name: Yves
full_name: Dubief, Yves
last_name: Dubief
- first_name: Markus
full_name: Holzner, Markus
last_name: Holzner
- first_name: Christof
full_name: Schäfer, Christof
last_name: Schäfer
- first_name: Alexander
full_name: Morozov, Alexander
last_name: Morozov
- first_name: Christian
full_name: Wagner, Christian
last_name: Wagner
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Samanta D, Dubief Y, Holzner M, et al. Elasto-inertial turbulence. PNAS.
2013;110(26):10557-10562. doi:10.1073/pnas.1219666110
apa: Samanta, D., Dubief, Y., Holzner, M., Schäfer, C., Morozov, A., Wagner, C.,
& Hof, B. (2013). Elasto-inertial turbulence. PNAS. National Academy
of Sciences. https://doi.org/10.1073/pnas.1219666110
chicago: Samanta, Devranjan, Yves Dubief, Markus Holzner, Christof Schäfer, Alexander
Morozov, Christian Wagner, and Björn Hof. “Elasto-Inertial Turbulence.” PNAS.
National Academy of Sciences, 2013. https://doi.org/10.1073/pnas.1219666110.
ieee: D. Samanta et al., “Elasto-inertial turbulence,” PNAS, vol.
110, no. 26. National Academy of Sciences, pp. 10557–10562, 2013.
ista: Samanta D, Dubief Y, Holzner M, Schäfer C, Morozov A, Wagner C, Hof B. 2013.
Elasto-inertial turbulence. PNAS. 110(26), 10557–10562.
mla: Samanta, Devranjan, et al. “Elasto-Inertial Turbulence.” PNAS, vol.
110, no. 26, National Academy of Sciences, 2013, pp. 10557–62, doi:10.1073/pnas.1219666110.
short: D. Samanta, Y. Dubief, M. Holzner, C. Schäfer, A. Morozov, C. Wagner, B.
Hof, PNAS 110 (2013) 10557–10562.
date_created: 2018-12-11T11:59:44Z
date_published: 2013-06-25T00:00:00Z
date_updated: 2021-01-12T06:59:54Z
day: '25'
department:
- _id: BjHo
doi: 10.1073/pnas.1219666110
external_id:
pmid:
- '23757498'
intvolume: ' 110'
issue: '26'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3696777/
month: '06'
oa: 1
oa_version: Submitted Version
page: 10557 - 10562
pmid: 1
publication: PNAS
publication_status: published
publisher: National Academy of Sciences
publist_id: '4073'
quality_controlled: '1'
scopus_import: 1
status: public
title: Elasto-inertial turbulence
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 110
year: '2013'
...
---
_id: '2829'
abstract:
- lang: eng
text: Laminar-turbulent intermittency is intrinsic to the transitional regime of
a wide range of fluid flows including pipe, channel, boundary layer, and Couette
flow. In the latter turbulent spots can grow and form continuous stripes, yet
in the stripe-normal direction they remain interspersed by laminar fluid. We carry
out direct numerical simulations in a long narrow domain and observe that individual
turbulent stripes are transient. In agreement with recent observations in pipe
flow, we find that turbulence becomes sustained at a distinct critical point once
the spatial proliferation outweighs the inherent decaying process. By resolving
the asymptotic size distributions close to criticality we can for the first time
demonstrate scale invariance at the onset of turbulence.
article_number: '204502'
author:
- first_name: Liang
full_name: Shi, Liang
id: 374A3F1A-F248-11E8-B48F-1D18A9856A87
last_name: Shi
- first_name: Marc
full_name: Avila, Marc
last_name: Avila
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Shi L, Avila M, Hof B. Scale invariance at the onset of turbulence in couette
flow. Physical Review Letters. 2013;110(20). doi:10.1103/PhysRevLett.110.204502
apa: Shi, L., Avila, M., & Hof, B. (2013). Scale invariance at the onset of
turbulence in couette flow. Physical Review Letters. American Physical
Society. https://doi.org/10.1103/PhysRevLett.110.204502
chicago: Shi, Liang, Marc Avila, and Björn Hof. “Scale Invariance at the Onset of
Turbulence in Couette Flow.” Physical Review Letters. American Physical
Society, 2013. https://doi.org/10.1103/PhysRevLett.110.204502.
ieee: L. Shi, M. Avila, and B. Hof, “Scale invariance at the onset of turbulence
in couette flow,” Physical Review Letters, vol. 110, no. 20. American Physical
Society, 2013.
ista: Shi L, Avila M, Hof B. 2013. Scale invariance at the onset of turbulence in
couette flow. Physical Review Letters. 110(20), 204502.
mla: Shi, Liang, et al. “Scale Invariance at the Onset of Turbulence in Couette
Flow.” Physical Review Letters, vol. 110, no. 20, 204502, American Physical
Society, 2013, doi:10.1103/PhysRevLett.110.204502.
short: L. Shi, M. Avila, B. Hof, Physical Review Letters 110 (2013).
date_created: 2018-12-11T11:59:49Z
date_published: 2013-05-13T00:00:00Z
date_updated: 2021-01-12T07:00:00Z
day: '13'
department:
- _id: BjHo
doi: 10.1103/PhysRevLett.110.204502
ec_funded: 1
external_id:
arxiv:
- '1304.5446'
intvolume: ' 110'
issue: '20'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://arxiv.org/abs/1304.5446
month: '05'
oa: 1
oa_version: Preprint
project:
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '306589'
name: Decoding the complexity of turbulence at its origin
- _id: 2511D90C-B435-11E9-9278-68D0E5697425
grant_number: SFB 963 TP A8
name: Astrophysical instability of currents and turbulences
publication: Physical Review Letters
publication_status: published
publisher: American Physical Society
publist_id: '3970'
quality_controlled: '1'
scopus_import: 1
status: public
title: Scale invariance at the onset of turbulence in couette flow
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 110
year: '2013'
...
---
_id: '2834'
abstract:
- lang: eng
text: Although the equations governing fluid flow are well known, there are no analytical
expressions that describe the complexity of turbulent motion. A recent proposition
is that in analogy to low dimensional chaotic systems, turbulence is organized
around unstable solutions of the governing equations which provide the building
blocks of the disordered dynamics. We report the discovery of periodic solutions
which just like intermittent turbulence are spatially localized and show that
turbulent transients arise from one such solution branch.
article_number: '224502'
author:
- first_name: Marc
full_name: Avila, Marc
last_name: Avila
- first_name: Fernando
full_name: Mellibovsky, Fernando
last_name: Mellibovsky
- first_name: Nicolas
full_name: Roland, Nicolas
last_name: Roland
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Avila M, Mellibovsky F, Roland N, Hof B. Streamwise-localized solutions at
the onset of turbulence in pipe flow. Physical Review Letters. 2013;110(22).
doi:10.1103/PhysRevLett.110.224502
apa: Avila, M., Mellibovsky, F., Roland, N., & Hof, B. (2013). Streamwise-localized
solutions at the onset of turbulence in pipe flow. Physical Review Letters.
American Physical Society. https://doi.org/10.1103/PhysRevLett.110.224502
chicago: Avila, Marc, Fernando Mellibovsky, Nicolas Roland, and Björn Hof. “Streamwise-Localized
Solutions at the Onset of Turbulence in Pipe Flow.” Physical Review Letters.
American Physical Society, 2013. https://doi.org/10.1103/PhysRevLett.110.224502.
ieee: M. Avila, F. Mellibovsky, N. Roland, and B. Hof, “Streamwise-localized solutions
at the onset of turbulence in pipe flow,” Physical Review Letters, vol.
110, no. 22. American Physical Society, 2013.
ista: Avila M, Mellibovsky F, Roland N, Hof B. 2013. Streamwise-localized solutions
at the onset of turbulence in pipe flow. Physical Review Letters. 110(22), 224502.
mla: Avila, Marc, et al. “Streamwise-Localized Solutions at the Onset of Turbulence
in Pipe Flow.” Physical Review Letters, vol. 110, no. 22, 224502, American
Physical Society, 2013, doi:10.1103/PhysRevLett.110.224502.
short: M. Avila, F. Mellibovsky, N. Roland, B. Hof, Physical Review Letters 110
(2013).
date_created: 2018-12-11T11:59:50Z
date_published: 2013-05-29T00:00:00Z
date_updated: 2021-01-12T07:00:05Z
day: '29'
department:
- _id: BjHo
doi: 10.1103/PhysRevLett.110.224502
ec_funded: 1
external_id:
arxiv:
- '1212.0230'
intvolume: ' 110'
issue: '22'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://arxiv.org/abs/1212.0230
month: '05'
oa: 1
oa_version: Preprint
project:
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '306589'
name: Decoding the complexity of turbulence at its origin
publication: Physical Review Letters
publication_status: published
publisher: American Physical Society
publist_id: '3965'
quality_controlled: '1'
scopus_import: 1
status: public
title: Streamwise-localized solutions at the onset of turbulence in pipe flow
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 110
year: '2013'
...