Experiments on Turbulence in Stratified Rotating Flows

Abstract

The evolution and interaction of approximately two-dimensional flows is of considerable importance to the dynamics of the atmosphere and oceans. The inability to stretch vortex lines in such flows leads to the inverse cascade of energy from small to large scales. The large scales develop into coherent structures containing much of the overall energy of the flow. With the lack of fine scales to dissipate the energy, the coherent structures persist for many eddy turnover times. Dissipation is confined mainly to periods of time when the coherent structures are interacting with each other, interactions which tend to produce the higher gradients and finer scales normally absent. These interactions have been studied numerically (e.g. Dritschel, 1993) and experimentally (e.g. van Heijst & Flór, 1989) for simple systems