CHAPTER XI - THE INTERSECTION OF SURFACES OF DISCONTINUITY

Abstract

This chapter discusses the interaction of surfaces of discontinuity. The line of intersection of two shock waves is, mathematically, a singular line of two functions describing the gas flow. The vertex of an acute angle on the surface of a body past which the gas flows is always such a singular line. It is found that the gas flow near the singular line can be investigated in a general manner. The flow pattern near this line consists of a number of sectors, which contain either uniform flow or a rarefaction wave. The velocity component parallel to the line of intersection must be the same in all regions round the line of intersection and can therefore be made to vanish by an appropriate choice of the coordinate system. An important part in the phenomenon of steady intersection of shock waves with the surface of a body is played by their interaction with the boundary layer. The steady intersection of strong shock waves with a solid surface is impossible. A solid surface can intersect only weak shock waves. The maximum permissible intensity of the shock wave also depends on whether the boundary layer is laminar or turbulent.