Atmospheric flow over a succession of nearly two‐dimensional ridges and valleys

Observations of neutral static stability flow in a nearly two‐dimensional valley are presented. Upstream and downstream of the valley are a succession of similar ridges and valleys. The valley sides have a slope of about 32° to the horizontal and when the wind is nearly perpendicular to the valley there is a marked flow separation. The observations of mean flow and turbulence are compared with numerical simulations of flow over periodic two‐dimensional ridges and valleys.