The combined effects of buoyancy, rotation, and shear on phase boundary evolution

Abstract

We use well-resolved numerical simulations to study the combined effects of buoyancy, pressuredriven shear and rotation on the melt rate and morphology of a layer of pure solid overlying its liquid phase in three dimensions at a Rayleigh number Ra = 1.25×10 5 . During thermal convection we find that the rate of melting of the solid phase varies non-monotonically with the strength of the imposed shear flow. In the absence of rotation, depending on whether buoyancy or shear is dominant, we observe either domes or ridges aligned in the direction of the shear flow respectively. Furthermore, we show that the geometry of the phase boundary has important effects on the magnitude and evolution of the heat flux in the liquid layer. In the presence of rotation, the strength of which is characterized by the Rossby number (Ro), we observe that for Ro = O(1) the mean flow in the interior is perpendicular to the direction of the constant applied pressure gradient. As the magnitude of the applied horizontal pressure gradient increases, the geometry of solid-liquid interface evolves from the voids characteristic of melting by rotating convection, to grooves oriented perpendicular to or aligned at an oblique angle to the applied pressure gradient.