The Influence of Concave Wedge Tips on Shock Reflection Patterns

The subject of this chapter is a combined, numerical and experimental, inquiry on a recently discovered shock reflection phenomenon, namely the dependence of the eventually established reflection pattern on the geometry of the initial portion of the reflecting surface, even if this initial portion comprises only a small part of the reflector. More specifically, it was demonstrated recently [1] in numerical simulations of shock wave reflection from wedges that the resulting reflection pattern may be of regular or irregular type for the same wedge angle, incident shock Mach number, and ratio of specific heats, depending on whether the tip of the reflecting wedge is straight or initially curved. Subsequent numerical studies [2] pointed to an interesting possibility that even a minuscule tip could possibly be the cause of differing reflection patterns, see Fig. 1. In this chapter, parametric numerical studies of the phenomenon are carried out with the goal of explaining it and establishing the range of flow and geometrical parameters in which the effect takes place. Furthermore, it is attempted to obtain the first experimental demonstration of the influence of the wedge tip on the resulting reflection pattern.