Dispersion of Shock Wave Transmitted Into Non-Uniform Materials

When a shock wave is incident on an obstacle, it is not only reflected back but also transmitted into the obstacle itself. The transmitted shock wave has not been fully investigated so far, compared with the reflected shock wave. In actual situations, the behavior and the characteristics of the transmitted shock wave are also of importance. In battlefields, human bodies are often subject to explosions and resulting shock waves. In particular, severe damage can be caused when a shock wave is transmitted into the human brain. In the present study, we conducted experiments to investigate the behavior and intensity of a shock wave, after it is transmitted into various materials. The materials used were sintered metal, silicone, and polyethylene foam. They were fixed on a specially devised model with a cavity, by which the resulting wave after a shock wave is transmitted could be observed. In order to understand what is happening in sintered metal, a 2-D model made of straws was devised and used.

Shock Wave Propagation Into a Dust-Gas Suspension Inside a Double-Bend Conduit

Using conduits in which a transmitted shock wave experiences abrupt changes in its direction of propagation is an effective means for shock wave attenuation. An additional attenuation of the transmitted shock wave is obtained when the medium contained inside the conduit (through which the shock wave is transmitted) is a suspension rather than a pure gas. The present numerical study shows that adding small solid particles (dust) into the gaseous phase results in sharp attenuation of all shock waves passing through the conduit. It is shown that the smaller the dust particles diameter is, the higher the shock attenuation becomes. Increasing the dust mass loading in the suspension also causes a quick attenuation. By proper choice of dust mass loading in the suspension, or the particles diameter, it is possible to ensure that the emerging wave from the conduit exit channel is a (smooth) compression wave, rather than a shock wave.