This thesis presents the formulation, evaluation and application of a method for predicting the streamwise development of turbulent shear flows, and the three chapters relate respectively to these three aspects of the work.

The theoretical analysis of Chapter I is based on the energy equilibrium hypothesis and relates the turbulent shear stress to the mean rates of strain in the flow. The streamwise developments of wall jets, free jets, wakes and other similar shear flows can be predicted using this analysis.

Two groups of measurements are presented in Chapter II:​ the first provides verification of the energy equilibrium hypothesis through intermittency measurements in a variety of shear flows;​ the second supplies measured mean flow developments which can be compared directly with the theoretical predictions of Chapter I.

Chapter III presents an application of the wall jet analysis in predicting the point of separation of a boundary layer, augmented by blowing, on an aerofoil with a trailing edge flap. The effects and requirements of a blowing slot located near the leading edge or, alternatively, near the flap wing junction, have been examined theoretically and the minimum blowing momentum required to suppress separation completely has been found for a variety of flap deflection angles .