ABSTRAKT

Stably-stratified flow of water through a channel with infinite side walls is studied using large eddy simulation. Mean shear in the horizontal plane promotes turbulence while the orthogonal buoyancy force tends to inhibit vertical fluctuations. The variation of horizontal momentum transport and vertical mass transport as a function of the generalized Richardson number, a measure of stratification relative to shear, is obtained. It is found that turbulence remains three-dimensional allowing vertical transport. Although the vertical eddy diffusivity decreases with increasing value of the local gradient Richardson number, it is generally larger than that in the more typical situation of flow in a channel with vertical shear.