Effect of finite plate length on supersonic turbulent boundary layerwith large distributed surface injection

The two-dimensional, supersonic, turbulent boundary layer on a finite length flat plate with large injection is analyzed using integral moment methods which include the interaction between the viscous and inviscid flows. Data obtained at Mm = 2.6 are presented and show agreement with the analysis. As injection is increased, the velocity profiles become inflected, the sonic line moves away from the wall and the flow becomes "subcritical." Under this condition, the effect of termination of injection can be felt upstream of the end of injection. In particular, as injection rates approaching the maximum value which can be entrained by a constant pressure mixing layer are approached, the analysis predicts that virtually the entire blowing region experiences a falling pressure due to the effect of finite length. It is postulated that this effect provides for a smooth transition from a boundary-layer flow to one where mixing is negligible, except in a thin layer near the streamline which divides the injected and freestream gas.