Analytical Surface Pressure and Drag for Linear Hydrostatic Flow over Three-Dimensional Elliptical Mountains

Abstract

A linear hydrostatic model of the flow of stably stratified air over a three-dimensional mountain with an elliptical horizontal cross section is considered. Analytical expressions for the surface pressure perturbation are used to study the differences between two- and three-dimensional flows. The horizontal divergence and lateral streamline deflection associated with the velocity component perpendicular to the mean flow are also considered. The force exerted on the mountain by the incoming airstream is determined as a function of the barrier eccentricity and orientation. If the upstream flow is not parallel to a symmetry axis of the terrain, there is a transverse force on the air which can be an appreciable fraction of the drag force acting in the direction opposite to the mean wind.