Attenuation of shock wave by porous materials

Abstract

Attenuations of shocked gas flow propagating through porous materials, are investigated experimentally and numerically. Process of shock attenuation occurs when shocked gas flow travel through porous materials such as polyurethane foam or wire mesh. Foams used have high-porosities phi(g) = 0.951 similar to 0.977 and low densities rho(c) = 27.6 similar to 55.8 kg/m(3), while the wire mesh has low-porosity phi(g) = 0.36. Shock tube experiments are conducted by using a shock tube with 50 mm in diameter and 6.4m in length. Pressures behind the fixed foam were decreased from the incident shocked pressure, which implies that the shock wave was well degenerated, and in some cases into compression waves. Pressure attenuation factor K-a caused by the presence of foam was estimated to be about 60 similar to 75 % of the value in the absence of foam value.