NUMERICAL INVESTIGATION OF DIFFRACTION, FOCUSING AND REFLECTION OF TOROIDAL SHOCK WAVES
环形激波绕射, 反射和聚焦的数值模拟研究

An investigation of toroidal shock wave motion in a cylindrical shock tube is described in this paper. Numerical simulations were carried out by using dispersion controlled dissipation scheme (DCD scheme) and validated with experimental data. From the numerical results, the toroidal shock wave diffraction, focusing and reflection were discussed in detail. It was found out that the key factor of cylindrical shock focusing is the shock acceleration when diffracting shock waves propagate toward the axis of symmetry. Mach numbers of incident toroidal shock waves play an important role in shock wave diffraction and focusing. The toroidal shock waves focus at certain point on the axis of symmetry while usual cylindrical shock waves focus on the entire the axis of symmetry, therefore, the focusing effect resulting from the two cases of focusing points are different essentially.