Columnar Vortices in Rotating Turbulence

Strong rotation makes an underlying turbulent flow quasi-two-dimensional and thus opens the way for an inverse energy cascade. Recent numerical simulations show that under certain conditions, the energy is accumulated at the largest scales of the system, forming large-scale structures known as coherent vortex. We analytically describe the interaction of a coherent vortex with small-scale turbulent pulsations and obtain an equation that allows us to determine the radial velocity profile U(r) of a coherent vortex. When external rotation is fast, the velocity profiles of cyclones and anticyclones are identical to each other and are well described by the dependence U(r) ∝ ±rln(R/r), where R is the transverse size of the vortex. As the external rotation decreases, this symmetry disappears: the maximum velocity in cyclones is greater and the position of the maximum is closer to the axis of the vortex in comparison with anticyclones. Besides, our analysis shows that the size R of the anticyclone cannot exceed a certain critical value, which depends on the Rossby and Reynolds numbers. The maximum size of the cyclones is limited only by the system size under the same conditions. Our predictions are based on the linear evolution of turbulent pulsations on the background of the coherent vortex flow.