Convection in a fluid layer driven by internal dielectric heating

Abstract

This study investigates the convective behaviour of two dielectric fluids with different Prandtl numbers under microgravity, each of which is confined between two parallel electrodes at a given temperature, and subjected to internal dielectric heating. Three-dimensional direct numerical simulations reveal a rich sequence of flow regimes as the electric Rayleigh–Roberts number increases: stable hexagonal patterns, mixed hexagonal-square structures, dominant rectangular convection and time-dependent convection. We derive scaling laws for key dimensionless quantities, including energy densities, convective Reynolds number and Nusselt number, with strong agreement across two magnitudes of the control parameter. Finally, we observe a shift in the onset of convection, with the critical electric Rayleigh–Roberts number increasing as the thermoelectric coupling parameter decreases. These results offer new insights into the role of internal dielectric heating in convective pattern formation and energy transport.