Effect of Ship Speed on Bubble Wake Geometry Characters

In order to understand the effect of ship speed on bubble wake geometry characters, explore the effect law of different scale bubbles on wake, and provide theoretical basis for acoustic detection of ship bubble wake and torpedo wake homing, this study adopts parabolic Reynolds-averaged Navier-Stokes ( PRaNS) equations, the bubble transport equation and the k-ε turbulence model are used to estimate the bubble number density distribution in ship’s far field wakes, numerically simulates the ship bubble wake geometry characters under different speeds for two typical ships, and the results agree well with the experiments. It shows that ship speed has little effect on bubble wake geometry distribution, but has significant effect on bubble number density in ship wakes. The faster the speed of ship, the higher the bubble number density in the ship wakes with same wake age, and the clearer the wake character. The bubbles with 10 μm radius have the largest elevation, the bubbles with 52 μm radius have the smallest elevation, and the bubbles with radius between 30~ 50 μm live longest. So the wake detection should be focused on the bubbles with radius between 30~ 50 μm.