Experimental investigation on the shock-wave load attenuation by geometrical means

The pressures and loads induced on the center of the end-wall of a shock tube by a shock wave that passes through different types of obstacles are investigated. Efforts have been made to understand the effect of the obstacle geometry on the load development. The experiments were conducted in a shock tube apparatus in which a modular test section was implemented. It is found that for a single-obstacle setup, the effect of the geometry becomes dominant when the blockage ratio (i.e., the ratio of the non-open area to the overall cross section) is large. It is also found that the attenuation effect is more pronounced for general geometries, which form diverging-like nozzle. In the case of multi-obstacles geometry, the same sensitivity to the blockage ratio as in the single-obstacle case is found. However, amplification or attenuation of the shock-wave load on the center of the end-wall of a shock tube is observed when the number of the obstacles is increased. This is due to different trapping effects of the shock wave between the obstacle and the end-wall.