Swirling flows characteristics in a cylinder under effect of buoyancy

Abstract

Thermal buoyancy, induced by injection or by dif-ferential heating of a tiny rod is explored to control break-down in the core of a helical flow driven by the lid rotation of a cylinder. Three main parameters are required to charac-terize numerically the flow behavior; namely, the rotational Reynolds number Re, the cavity aspect ratio and the Richardson number Ri. Warm injection/rod, Ri > 0, is shown to prevent on-axis flow stagnation while breakdown en-hancement is evidenced when Ri [removed] 0). Besides, the emergence of such a toroidal mode was not found to occur under thermal stratification induced by a differentially heated rod. Moreover, three state dia-grams were established which provide detailed flow charac-teristics under the distinct and combined effects of buoy-ancy strength, viscous effects and cavity aspect ratio