Research on the estimate formulas for underwater explosion bubble jet parameters

The underwater explosion bubbles have significant applications in the military, but the characteristics of bubble jet near a solid wall are still not very clear. Due to convenience and high efficiency, the boundary integral method is used to study the characteristics of bubble jet in this paper. The shape of bubble jet is simplified to a cylindrical shape when the jet impacts on the opposite surface, so the characteristics of bubble jet are characterized by three parameters, including the cylindrical width (diameter), the cylindrical height and the jet velocity. By adjusting the charge weight W, the detonated depth H and the stand-off distance parameter γ (γ=(H−h)/Rm, where h is the depth of solid wall, and Rm is the maximum bubble radius), the relations of the bubble jet width, height and velocity with them are explored, where three appropriate mathematical models are selected. Finally, based on the least square method, three estimate formulas for bubble jet width, height and velocity are obtained, which have good accuracy to predict the bubble jet width, height and velocity when W = 50-1000 kg, h = 50-500 m and γ = 0.65-1.5. The purpose is to provide a reference for computing the damage of the bubble jet to structures in engineering.