Linear theory of stratified flow past an isolated mountain in isosteric coordinates

Abstract

The linear theory for hydrostatic nonrotating flow over an axisymmetric hill is redone in isosteric (ie constant specific volume) coordinates, thus allowing the lower boundary condition (LBC) to be exactly satisfied. This results in a more consistent flow field near the mountain and good agreement with recent numerical calculations. The formation and spread of a region of collapsed density surfaces is predicted on the leeward slope. Two incipient stagnation points are predicted, one on the windward slope and one some distance aloft, above the mountaintop. In satisfying the LBC exactly, a correction to the pressure arises which cancels the Bernoulii "height term' in Sheppard's blocking analysis. This makes it seem unlikely that Sheppard's kinetic energy argument plays any role in airflow blocking and splitting. -Author