Magnetic modulation of flow reversals in liquid metal thermal convection
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arXiv
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| Autori principali: | , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866914146517254144 |
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| author | Cao, Yan-Wu Ai, Ming-Zhu Chen, Long Yang, Juan-Cheng Ni, Ming-Jiu |
| author_facet | Cao, Yan-Wu Ai, Ming-Zhu Chen, Long Yang, Juan-Cheng Ni, Ming-Jiu |
| contents | Flow reversals are rarely observed in low-Prandtl-number liquid metal convection due to the fluid's exceptionally high thermal diffusivity. Here, we demonstrate that an external transverse magnetic field can induce such reversals in a quasi-two-dimensional (Q2D) rectangular cell with an aspect ratio ($\itΓ$) of $0.2$. Our experimental observations reveal that the system initially exhibits periodic dynamics at the onset of reversals before transitioning to stochastic behavior as the ratio of Rayleigh number ($Ra$) to Hartmann number ($Ha$) increases. This transition is governed by the competition between buoyancy and Lorentz forces, with experimental data showing a linear scaling relationship between $Ra$ and $Ha$ at critical points. We develop a theoretical model that incorporates magnetic field effects in low-Prandtl-number convection to predict the reversal frequencies. These findings provide new insights into how magnetic fields can modulate flow regimes in low-Prandtl-number convection, establishing a controlled framework for investigating reversal dynamics in magnetohydrodynamic systems. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2511_06819 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Magnetic modulation of flow reversals in liquid metal thermal convection Cao, Yan-Wu Ai, Ming-Zhu Chen, Long Yang, Juan-Cheng Ni, Ming-Jiu Fluid Dynamics Flow reversals are rarely observed in low-Prandtl-number liquid metal convection due to the fluid's exceptionally high thermal diffusivity. Here, we demonstrate that an external transverse magnetic field can induce such reversals in a quasi-two-dimensional (Q2D) rectangular cell with an aspect ratio ($\itΓ$) of $0.2$. Our experimental observations reveal that the system initially exhibits periodic dynamics at the onset of reversals before transitioning to stochastic behavior as the ratio of Rayleigh number ($Ra$) to Hartmann number ($Ha$) increases. This transition is governed by the competition between buoyancy and Lorentz forces, with experimental data showing a linear scaling relationship between $Ra$ and $Ha$ at critical points. We develop a theoretical model that incorporates magnetic field effects in low-Prandtl-number convection to predict the reversal frequencies. These findings provide new insights into how magnetic fields can modulate flow regimes in low-Prandtl-number convection, establishing a controlled framework for investigating reversal dynamics in magnetohydrodynamic systems. |
| title | Magnetic modulation of flow reversals in liquid metal thermal convection |
| topic | Fluid Dynamics |
| url | https://arxiv.org/abs/2511.06819 |