Experiments and simulations on self-organization of confined quasi-two-dimensional turbulent flows with discontinuous topography

Abstract

Decaying, quasi-two-dimensional turbulent flows in a rotating rectangular domain with a step-like topography are investigated by means of laboratory experiments and numerical simulations. The aim is to describe the role of a discontinuous topography on the evolution and organization of the vortices. Initially, vortex interactions lead to the self-organization of the flow, as in two-dimensional turbulence. Afterwards, the interaction of vortices with the step leads to a flow along the topography that always maintains the shallow region on the right. The simulations have revealed the existence of a critical value determined by the strength of the flow and the step height, after which structures are not able to cross the topography. As a result, the flow evolves almost independently at the shallow and deep regions affecting the efficiency of the organization and therefore the final distribution of vorticity. The existence of a preferential distribution of vorticity due to the step for long times (several rotation periods) is discussed. Different distributions are found when using slightly different flow parameters, and therefore the existence of such a preferential final state is analyzed by using statistical methods.