Study Of Numerical Simulation Of Underwater Explosion And Shallow Water Effects

The underwater explosion process and the effect of shallow underwater explosion are studied in this paper based on the simulation tool AUTODYN. The factors which may affect the shock wave simulation had been disccused. The simulation results show that a high element density is needed to get a good accuracy both in pressure and impulse simulation and SHOCK EOS is better than polynomial EOS in the simulation of pressure in far field. By comparing the simulation results with experimental data, it is found that the software is capable for shock wave simulation. The bubble pulse in deep water is also simulated in 1D model, and the simulation results are consistent with the experimental data in relative literatures. The dynamics behavior have been discussed by remapping the 1D resulsts on the 2D model; it is found that the bubble is not sphericity because of the existing of instability (Rayleigh-Taylor instability) on the boundary between gas and water. Based on the results dicussed above, the cutoff effects of shock wave have been simulated, and the simulation showed some basic laws of cutoff effects, such as the regular reflected rarefaction wave just work on the later period of shock wave but have no influence on the peak value, and the slope of cutoff line represents the intension of cutoff effects. Finally, the dynamic behavior of bubble and water surface in shallow underwater explosion have been simulated, and the effects in different situations, such as explosion in the same depth with different explosive mass and in different depth with identical explosive mass, were discussed.