THE REFLECTION OF A SHOCK-WAVE OVER A CONE

An investigation was made of the reflection of planar shock waves from cones. 86 cones, the half apex angle of which varied from 10 degrees to 52 degrees at every 0.5 degrees, were installed in a 60 mm x 150 mm diaphragmless shock tube equipped with holographic interferometry. Th e diaphragmless shock tube had a high degree of reproducibility with w hich the scatter of shock wave Mach number was within +/-0.25% for sho ck wave Mach number ranging from 1.16 to approximately 2.0. The reflec tion of shock waves over cones was visualized using double exposure ho lographic interferometry. Whitham's geometrical shck wave dynamics was used to analyse the motion of Mach stems over cones. It is found that for relatively smaller apex angles of cones trajectory angles of resu lting irregular reflections coincide with the so-called glancing incid ence angles and their Mach stems appear to be continuously curved from its intersection point with the incident shock wave, which shows the chractericstic of von Neumann reflection. The domain of the existence of the von Neumann reflection was analytically obtained and was found to be broadened much more widely than that of two-dimensional reflecti ons of shock waves over wedges.