ResumeThe effect of streamline curvature on turbulent shear flow in axisymmetric curved ducts (diffusers and nozzles) is investigated both the-oretically and experimentally. Both theory and experiment indicate that, with a thin inlet boundary layer, a concave diffuser gives as high value of pressure recovery as that given by a conical diffuser of the same area ratio, while for the case of thick inlet boundary layer, the convex diffuser gives the highest pressure recovery. The convex diffuser is least sensitive to thickening of inlet boundary layer and the convex nozzle was found to give the fastest pressure drop i.e. the highest exit Mach number.