Analysis of similarity laws in a pressure-gradient boundary layer over gentle obstacles

The pressure-gradient similarity theory has been applied to neutral boundary layers perturbed by the presence of 2-D topography, using wind tunnel data for tuning and comparison. It turns out that the vertical structure of the inner part of the boundary layer can be defined in terms of scales determined from the local horizontal surface pressure gradient and surface stress. The outer structure, on the other hand, is affected only by the upstream conditions.The similarity formulas are shown to be applicable to field cases, using simple model evaluations of the driving parameters. Proper data sets are almost totally lacking at present, limiting the possibility of detailed comparisons with real data.