NUMERICAL INVESTIGATION OF DIFFRACTION, FOCUSING AND REFLECTION OF TOROIDAL SHOCK WAVES

An investigation of toroidal shock wave motion in acylindrical shock tube is described in this paper. Numerical simulationswere carried out by using dispersion controlled dissipation scheme (DCDscheme) and validated with experimental data. From the numerical results,the toroidal shock wave diffraction, focusing and reflection were discussedin detail. It was found out that the key factor of cylindrical shockfocusing is the shock acceleration when diffracting shock waves propagatetoward the axis of symmetry. Mach numbers of incident toroidal shock wavesplay an important role in shock wave diffraction and focusing. The toroidalshock waves focus at certain point on the axis of symmetry while usualcylindrical shock waves focus on the entire the axis of symmetry, therefore,the focusing effect resulting from the two cases of focusing points aredifferent essentially.