MAGNETOHYDRODYNAMIC BUOYANCY-DRIVEN TURBULENCE IN THERMALLY STRATIFIED CONDUCTING FLOW

Magnetohydrodynamic (MHD) buoyancy-driven instability has much in common with gravity-driven natural convection instability in thermally stratified fluids, in that account must be taken of the temperature dependence of conductivity in the former case and of density in the latter case. Employing the Monin-Obukhov theory of mixed convection in a stratified atmosphere, temperature and velocity profiles in MHD turbulent shear flow are obtained. The problem of the boundary-layer development is solved, and the heat and momentum fluxes are found. It is shown that the buoyancy force effects drastically change the fluxes when the Stuart number exceeds unity. Anode-cathode asymmetry observed experimentally on MHD devices is explained.