Separation effects in Ekman layer flow over ridges

Two‐dimensional numerical integrations of the Navier‐Stokes equations for flow of an Ekman layer ove a ridge on a range of length scales corresponding to large Rossby numbers are presented. The results are compared, where appropriate, with numerical solutions of the triple deck equations of boundary layer flow For steady flow agreement is good and, as predicted by triple deck theory, the net change in total force or the domain is small for homogeneous flow. An increase in force arises either through gravity wave radiation when triple deck predictions agree well, or when the ridge is sufficiently steep to give eddy shedding.