Forced vortex merging and splitting events in ferrofluidic Couette flow
Time-dependent boundary conditions being an ubiquitous observation in numerous natural and industrial flows. However, to date the influence of such temporal modulations has been given minor attention. The present problem addresses ferrofluidic Couette flow in between co-rotating cylinders in a spati...
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2023 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/389770 |
| Acceso en línea: | https://hdl.handle.net/2117/389770 https://dx.doi.org/10.1016/j.jmmm.2023.170666 |
| Access Level: | acceso abierto |
| Palabra clave: | Shear flow Magnetic fluids Taylor vortices Taylor-Couette flow Vortex splitting and merging Ferrofluids Alternating magnetic field Time-dependent forcing Vòrtexs de Taylor Àrees temàtiques de la UPC::Física |
| Sumario: | Time-dependent boundary conditions being an ubiquitous observation in numerous natural and industrial flows. However, to date the influence of such temporal modulations has been given minor attention. The present problem addresses ferrofluidic Couette flow in between co-rotating cylinders in a spatially homogeneous magnetic field subject to time-periodic modulation. Using a modified Niklas approximation, we study the effect of amplitude and frequency modulation onto the the transition scenarios between different toroidal flow structures, nV states, via vortex merging and splitting. Thereby the system response appears to be quite sensitive/dependent on the driving frequency OH , which can cause a notable “delay” in the system response. Aside, as a result of the inertia of the ferrofluid, resisting the fast-changing accelerating Kelvin force, new, temporal nV states appear within an alternating field. These states are unstable under static fields. Finally we show that within the same nV state, while keeping similar flow dynamics, large discrepancies in angular momentum and torque can be observed. |
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