Experimental investigation of the Boundary Zonal Flow (BZF) in rotating turbulent convection*

We report on measurements in rotating turbulent Rayleigh-B\'enard convection, in a 2.20\, m high cylindrical cell of aspect ratio between its diameter and height of $\Gamma =1/2$. The working fluids are nitrogen and pressurized (up to 19\,bar) sulfur hexafluoride (SF$_6$). We cover a large Rayleigh number range of $5\times 10^9 \leq Ra\leq 5\times 10^{14}$ at Prandtl numbers in the range $0.74\leq Pr\leq 0.96$. Using thermal probes close to the cylindrical sidewalls we measure characteristic properties of the recently found boundary zonal flow (BZF) as a function of Ra and the rotation rate, i.e., the inverse Rossby number (1/Ro). We also discuss in our talk the influence of the BZF on the heat transport.