Compared to planar shock waves generated inside a shock tube, blast waves have three major peculiarities. First, blast waves have a sharp peak overpressure followed by a decaying pressure profile. Second, at the latter part of the decaying pressure profile, blast waves often have "negative pressure," which is lower than the initial pressure in the quiet region. Finally, a blast wave has a secondary shock wave, which is the reflection of the implosion shock wave generated by overexpansion of the combustion gas. To simulate the fluid dynamics of a blast wave from the point of view of blast injury, the pressure history should meet the characteristics described above. To generate blast-like shock waves in a shock tube, optimization of a high-pressure room has been performed both numerically and experimentally. The optimized high-pressure room provided both rapid pressure decay after the shock front and following negative pressure portion. Optimal conditions for the simulation of the blast shock waves were found using numerical calculations and compared with the experiments. A shock tube with the cross section of 50 mm by 50 mm, a 500-mm-long high-pressure room, a 3040-mm-long low-pressure channel, and a 23-mm-long middle-pressure chamber were used in the experiments. Negative pressure and rapid decay of pressure were observed inside the shock tube with a shortened high-pressure room. In addition, we expect that shock waves with a profile more resembling a bomb blast can be provided by using a detonation tube as a driver section.
shock wave, blast wave, blast simulator, detonation, shock tube