ON THE INTERACTION OF AN ISOLATED OBSTACLE WITH A ROTATING STRATIFIED SHEAR-FLOW

Consideration is given to the effects of upstream shear upon the flow of a rotating stratified fluid past an isolated obstacle. The vorticity equation governing the interaction of the flow with the obstacle is derived for the inertially-dominated regime, and it is demonstrated that the effect of increasing vertical shear in the undisturbed flow is to reduce the vertical penetration length of the topographic disturbance. Following Huppert (1975) and Johnson (1977), limiting cases of high and low stratification are investigated. Laboratory data are presented in qualitative support of the analytical results, and it is demonstrated that the vertical attenuation of the topographic disturbance is increased by an increase in the shear parameter. The effect is explained in terms of the increasing attenuating role of the local Rossby number at each successive elevation above the obstacle. © 1991, Taylor & Francis Group, LLC. All rights reserved.