The influence of gravity on heat transfer and flow structure in centrifugal convection under low rotation

We investigated the influence of gravity on heat transfer and flow structure in centrifugal convection under low rotation. The study focused on the role of the Froude number (Fr) under conditions of either constant axial Rayleigh number (Rag) or constant total Rayleigh number (Rat). Our findings indicate that, at constant Rag, the Nusselt number (Nu) initially decreases with increasing Fr, reaching a peak around Fr≈0.2. In contrast, under constant Rat, Nu exhibits a slight initial decrease followed by a gradual increase with increasing Fr. For Fr≤0.2, buoyancy due to gravity dominates thermal driving, resulting in an inclined temperature boundary layer. As Fr increases beyond 0.2, the centrifugal force becomes dominant, enhancing heat transfer and promoting a more uniform temperature boundary layer. At Fr≥5, the system exhibits characteristics similar to classical Rayleigh–Bénard convection, primarily influenced by strong centrifugal effects and weak axial flows. These insights enhance our understanding of heat transfer mechanisms influenced by combined gravity and rotation, offering potential optimizations for industrial heat transfer system designs and performance.