Magnetic field induced flow pattern reversal in a ferrofluidic Taylor-Couette system Altmeyer, Sebastian ; https://orcid.org/0000-0001-5964-0203 Do, Younghae Lai, Ying ddc:530 ddc:540 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. Nature Publishing Group 2015 info:eu-repo/semantics/article doc-type:article text http://purl.org/coar/resource_type/c_2df8fbb1 https://research-explorer.ista.ac.at/record/1589 https://research-explorer.ista.ac.at/download/1589/5036 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> eng info:eu-repo/semantics/altIdentifier/doi/10.1038/srep18589 info:eu-repo/semantics/altIdentifier/wos/000367075500002 info:eu-repo/semantics/openAccess