Magnetoconvection in a horizontal duct flow - A parametric study

Mixed convection flows in a horizontal duct with a heated bottom wall and a magnetic field imposed in the horizontal transverse direction are analyzed numerically using the two-dimensional approximation valid in the limit of strong magnetic field effect. A parametric study is carried out to understand the effect of the Reynolds, Hartmann, and Grashof numbers on the flow. The focus is on the convection instability of the quasi-two-dimensional states that occur under strong magnetic fields. The range of existence of such states is established. Linear stability analysis and simulations of nonlinear regimes demonstrate that high-amplitude low-frequency magnetoconvective fluctuations are generated by the instability in a broad range of parameters and that their strength is not diminished as the magnetic field becomes stronger. Good agreement with experimental data is found.

Automated summary

This paper numerically analyzes mixed convection flows in a horizontal duct with a heated bottom wall and a magnetic field imposed in the horizontal transverse direction using the two-dimensional approximation. The effect of Reynolds, Hartmann, and Grashof numbers on the flow is studied, with a focus on the convection instability of quasi-two-dimensional states under strong magnetic fields. The study establishes the range of existence of such states and demonstrates that high-amplitude low-frequency magnetoconvective fluctuations are generated by the instability in a broad range of parameters, with their strength unaffected by increasing magnetic field. Good agreement with experimental data is found.