Altmeyer, SebastianIST Austria ; Do, Younghae ; Lai, Ying
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.
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
Altmeyer, S., Do, Y., & Lai, Y. (2015). Magnetic field induced flow pattern reversal in a ferrofluidic Taylor-Couette system. Scientific Reports, 5. https://doi.org/10.1038/srep18589
Altmeyer, Sebastian, Younghae Do, and Ying Lai. “Magnetic Field Induced Flow Pattern Reversal in a Ferrofluidic Taylor-Couette System.” Scientific Reports 5 (2015). https://doi.org/10.1038/srep18589.
S. Altmeyer, Y. Do, and Y. Lai, “Magnetic field induced flow pattern reversal in a ferrofluidic Taylor-Couette system,” Scientific Reports, vol. 5, 2015.
Altmeyer S, Do Y, Lai Y. 2015. Magnetic field induced flow pattern reversal in a ferrofluidic Taylor-Couette system. Scientific Reports. 5, 18589.
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.
IST-2016-472-v1+1_srep18589.pdf 2.77 MB