ON REFLECTION OF SHqCK WAVES FROM BOUNDARY LAYERS

Measurements of the reflection characteristics of shock waves from a flat surface with a laminar and turbulent boundary layer are presented. ' The investigations were carried out at Mach numbers from about 1.3 to 1.5 and a Reynolds number-of 0.9 x 106• The difference in the shock-wave interaction with laminar and tur-bulent boundary layers, first found in transonic flow, is confirmed and·- investigated in detail for supersonic flow. The relative upstream I. influence of a shock wave impinging on a given boundary layer has been measured for both laminar and turbulent layers., The upstream influence of a ' shock wave in the laminar layer is found to be of the order of 50 boundary~layer thicknesses as compared with about 5 in the turbulent case. Separation,almost always occurs in.the laminar boundary layer. The separation is restric.ted to a region of finite extent upstream of, the shock wave. In the turbulent case no separation was found. A' model of the flow near the point of impingement of the shock wave on.the boundary layer is given for both cases. T.he difference between impulse-type and step-type shock waves is discussed and their inter-action with the boundary layer is compared. Some general considerations on the experimental production of shock waves from wedges and cones are presented, as well as a discussion of boundary layer.in supersonic flow. A'few examples of reflection of shock waves from supersonic shear layers are also presented