Oscillatory flow in a rotating annular pool with radial temperature and solute concentration gradients

This paper presents a series of three-dimensional numerical simulations to investigate the oscillatory flow induced by the surface tension, buoyancy and rotation in an annular pool. The annular pool is filled with the silicon-germanium melt and rotates around the vertical axis at different Taylor numbers ranging from 0 to 1200. The surface tension gradient is induced by the temperature and solute concentration differences. It is assumed that the thermal and solutal capillary effects are opposite and of equal magnitude. Results reveal that the pool rotation can suppress the radial flow by changing the solute concentration distribution. It remarkably influences the flow structure and the flow stability of the basic flow. When the thermal capillary Reynolds number exceeds a critical value, the basic flow would bifurcate to two types of oscillatory convection, depending on the Taylor number. With the increase of Taylor number, the critical thermal capillary Reynolds number increases first, then decreases rapidly once it reaches the inflection point. At last, it keeps at almost a constant level. The evolutions of flow pattern with thermal capillary Reynolds number at different Taylor numbers are obtained. It reveals that the characteristics of these flow patterns are strongly dependent on the Taylor number and the thermal capillary Reynolds number. Corresponding formation mechanisms of these flow patterns are also discussed. (C) 2019 Published by Elsevier Ltd.