Abstract
Focusing of a toroidal shock wave emitted from a co-axial annular shock tube and the resulting shock wave reflection were studied numerically with a dispersion-controlled scheme. A shock wave discharged from an open-end of a circular shock tube into ambient air was calculated first for comparison with an experimental interferogram. After obtaining good agreement, further three cases were calculated with various initial shock Mach numbers. It was found that intense shock focusing appears when toroidal shock waves merge at the axis of symmetry. A somewhat unusual shock wave reflection was also observed in the case of higher shock Mach numbers.
