Interaction of underwater explosion bubble pair below a rigid wall

This paper presents numerical studies of the interaction of synchronized underwater explosion (UNDEX) bubble pair below a rigid wall. The compressible Eulerian finite element method (EFEM) is adopted here to simulate the interaction of bubble pair, which involves the bubble jetting, coalescence, and splitting. The numerical data including the behavior of bubble pair and corresponding pressures matched well with the UNDEX experimental results. Load pressures caused by both the explosion shock wave and the bubbles' collapse on the wall centroid are analyzed. Effects of crucial parameters containing buoyancy parameter δ, inter-bubble distance, γbb, and upper bubble–wall distance, γbw, on the interaction of bubble pair are discussed. The load pressures caused by the bubble pair are compared with those caused by a single bubble (with the same energy as the sum of bubble pair) below a rigid wall over a range of distance parameters. Comparative results show that the pressure caused by the bubble pair on the wall centroid can be enhanced by adjusting the parameters of δ, γbb, and γbw. This suggests an applicable method on how to increase loads caused by synchronized bubble pair and enhance the resultant damage to the structure nearby, by simply controlling the buoyancy parameter and the initial distance parameters of the bubble pair system.