Ryuma Kawamura

Reflection of Shock Waves–1 Pseudo-Stationary Case

Results of theoretical and experimental investigations on shock reflection at a fixed wall are reported in this paper. In the region of regular reflection, agreement of theory and experiment is found to be good except for the fact that experimental points extend a litter bit beyond the theoretical limit. A theoretical investigation of the flow characteristics is made on Mach reflection cases with the conclusion that a singularity would appear at the triple point, and hence, the reflected shock angle would not coincide with the theoretical one when the flow is subsonic behind the reflected shock. This theoretical prediction is fully confirmed by the results of shock angle measurement in schlieren pictures obtained by the experiment. In case of a strong incident shock, angle of the reflected shock decreases discontinuously at the transition from regular to Mach reflection as expected from the theory. In case of a weak incident shock, on the other hand, its change is continuous against the ordinary three-sho...

A Study on the Attenuation of Shock Waves due to Obstacles in the Passage

Results are reported of a shock-tube experiment on the retardation of shock waves due to obstacles in the passage. A one-dimensional analysis is applied on the flow field resulting from the interaction of shocks and obstacles, and a theoretical relation between the attenuation of shocks and the resistance of the passage is derived. The drag coefficients of a series of simple bluff obstacles used in the experiment are estimated. Comparisons with available steady-flow data are made along with some discussions.