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arXiv · 1812.06422

Transitions near the onset of low Prandtl-number rotating magnetoconvection

Manojit Ghosh·Paromita Ghosh·Yada Nandukumar·Pinaki Pal
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Abstract

We investigate the onset of convective instability and subsequent transitions near it in Rayleigh-B\'enard convection (RBC) of electrically conducting low Prandtl-number (Pr) fluids in the simultaneous presence of rotation about the vertical axis and external uniform horizontal magnetic field with free-slip boundary conditions. Both three dimensional direct numerical simulations (DNS) and low dimensional modeling of the system have been performed for the investigation. DNS results show a plethora of patterns near the onset of convection for weak magnetic field. Most interestingly, the Nusselt number (Nu) computed from the DNS data for relatively stronger magnetic field shows a sharp jump at the onset, indicating substantial enhancement of the convective heat transfer. The origin of these flow patterns, as well as the reason for a notable increase of heat transfer near the onset of convection, are then explained using low dimensional models constructed from DNS data.

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Manojit Ghosh, Paromita Ghosh, Yada Nandukumar, Pinaki Pal. 2018-12-16. Transitions near the onset of low Prandtl-number rotating magnetoconvection. https://arxiv.org/abs/1812.06422

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