Abstract: Numerical simulation for modeling the cavity formation process of high-speed water entry is performed. Finite volume method is introduced to discretize the Reynolds averaged Navier-Stokes equations. Results on the velocity and trajectory show good agreement with the results obtained by the analytical model. The flowing characteristics and pressure distribution of the deep closure stage are also studied. Results show that the deep closure occurs after surface closure and at a deep penetration depth for high-speed water entry problem, and the cavity collapses very quickly after the deep closure. The cavity closes under the effects of multiphase flow before the cavity wall shrinks completely, which induces high pressure around the deep closure area, and the maximum pressure always act on the separating points until the cavity collapses.

Key words: fluid mechanics, multiphase flow, high-speed water entry, cavity, deep closure