article published yes Sebastian Altmeyer author 2EE67FDC-F248-11E8-B48F-1D18A9856A870000-0001-5964-0203 Younghae Do author Ying Lai author BjHo department 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. https://research-explorer.ista.ac.at/download/1589/5036/IST-2016-472-v1+1_srep18589.pdf application/pdfno Nature Publishing Group2015 eng 00036707550000210.1038/srep18589 5 Altmeyer, Sebastian, Younghae Do, and Ying Lai. “Magnetic Field Induced Flow Pattern Reversal in a Ferrofluidic Taylor-Couette System.” <i>Scientific Reports</i>. Nature Publishing Group, 2015. <a href="https://doi.org/10.1038/srep18589">https://doi.org/10.1038/srep18589</a>. Altmeyer, Sebastian, et al. “Magnetic Field Induced Flow Pattern Reversal in a Ferrofluidic Taylor-Couette System.” <i>Scientific Reports</i>, vol. 5, 18589, Nature Publishing Group, 2015, doi:<a href="https://doi.org/10.1038/srep18589">10.1038/srep18589</a>. Altmeyer S, Do Y, Lai Y. Magnetic field induced flow pattern reversal in a ferrofluidic Taylor-Couette system. <i>Scientific Reports</i>. 2015;5. doi:<a href="https://doi.org/10.1038/srep18589">10.1038/srep18589</a> S. Altmeyer, Y. Do, and Y. Lai, “Magnetic field induced flow pattern reversal in a ferrofluidic Taylor-Couette system,” <i>Scientific Reports</i>, vol. 5. Nature Publishing Group, 2015. Altmeyer, S., Do, Y., &#38; Lai, Y. (2015). Magnetic field induced flow pattern reversal in a ferrofluidic Taylor-Couette system. <i>Scientific Reports</i>. Nature Publishing Group. <a href="https://doi.org/10.1038/srep18589">https://doi.org/10.1038/srep18589</a> Altmeyer S, Do Y, Lai Y. 2015. Magnetic field induced flow pattern reversal in a ferrofluidic Taylor-Couette system. Scientific Reports. 5, 18589. S. Altmeyer, Y. Do, Y. Lai, Scientific Reports 5 (2015). 15892018-12-11T11:52:53Z2025-09-23T09:32:24Z