Diffusion‐Free Scaling in Rotating Spherical Rayleigh‐Bénard Convection

Direct numerical simulations are employed to reveal three distinctly different flow regions in rotating spherical Rayleigh‐Bénard convection. In the high‐latitude region [Formula: see text] vertical (parallel to the axis of rotation) convective columns are generated between the hot inner and the cold outer sphere. The mid‐latitude region [Formula: see text] is dominated by vertically aligned convective columns formed between the Northern and Southern hemispheres of the outer sphere. The diffusion‐free scaling, which indicates bulk‐dominated convection, originates from this mid‐latitude region. In the equator region [Formula: see text] , the vortices are affected by the outer spherical boundary and are much shorter than in region [Formula: see text].