Boundary Zonal Flow (BZF) in rotating turbulent convection*

We report the discovery and overall properties of a wall-localized mode of turbulent, rotating thermal convection, denoted as a boundary zonal flow (BZF). We use both direct numerical simulation and experimental measurements to investigate the BZF mode that emerges strongly in cylindrical cells with diameter to height ratios $\Gamma < 1$ and that appears to play a similar role for rotating convection as does the large scale circulation (LSC) of non-rotating convection.  The coherent precessing structure of the BZF is manifest in bimodal temperature distributions and in very significant concentration of vertical heat transport near the boundary.  The consequences of the BZF for the study of turbulent rotating thermal convection are discussed.