In many applications of boundary-layer control by tangential blowing the surface downstream of the blowing slot is likely to be strongly curved. For example, this is the case when blowing around a bluff trailing edge is used to control the circulation around an aerofoil as described in ref. 1. The flow involved in such cases is that of a curved wall jet in an adverse pressure gradient. A knowledge of the radial and tangential pressure distributions in the curved wall jet is required if development of the flow and separation are to be predicted.