Research on the effect of asymmetric bubbles on the load characteristics of projectiles during an underwater salvo

This paper analyzes the effect of bubbles on the load characteristic of projectiles launched underwater with transverse-flow under different dimensionless launch time intervals. The realizable k−ε turbulence model and energy equation, as well as the volume of fluid method and overlapping grid technique, were adopted. Additionally, validations of numerical approach and grids independence validation were carried out. Evolution of bubbles at tube outlet, time-domain characteristic and frequency domain characteristic of lateral force, vertical force-torque, and motion characteristics are studied. The results show that spilled gas from the tube outlet fuses and moves in a transverse-flow direction. The pressure pulsation, which is caused by the bubble elastic effect, leads to high-frequency pulsation laws of the load characteristic. In the initial stage of the movement, the motion laws of projectiles under different launch time intervals are similar. At ΔT≤1.2, the flow interference between two projectiles is large, which seriously affects the ballistic stability and safety.