Computer Simulation Studies on Free Surface Reflection of Underwater Shock Waves

摘要

A computer simulation was used to study the irregular surface rarefaction phenomena produced by an underwater shock wave generated from a strong point explosion. We simulated the explosions with energies near 10 sup 15 joules at three depths (3 m, 21 m, and 66.5 m) and computed the shock propagation until the peak pressure decayed to less than 0.1 GPa (1 Kbar). The simulations permitted the determination of the onset point of irregular rarefaction on the surface, and of the envelope separating the irregular and regular-rarefaction regions. The theoretical predictions of the onset points are consistent with the code results for all three cases. However, the predicted region boundaries, which are calculated from the arrival of the first rarefaction signal, are in agreement with the simulation results only in the weak shock case (DOB = 66.5 m). For the strong and intermediate shock cases (DOB = 3 m and 21 m, respectively), agreement was not obtained. The implication of the discrepancy in these cases is discussed. 9 refs., 8 figs. (ERA citation 12:041871)