高速旋转小球入水空泡特性数值模拟

Water-entry cavities of high-speed spinning sphere (HSS) were investigated numerically based on the volume of fluid (VOF) multiphase flow model, the k-ω model and dynamic grid technique. After analyzed and compared the published papers about the water entry, the optimum numerical models were selected, and a numerical simulation system was established suitable for HSS. The evolutionary process of cavities induced by water-entry HSS with different velocity and specific weight was discussed. The reverse lift offset phenomenon was detected during water-entry process within the depth of 0.25d. The trajectories of water-entry HSS with identical specific weight but different velocities are similar in the initial stages of entry. And the curvature of trajectories of those with larger specific weight but identical velocity gets smaller. The twice-closure phenomenon, vertical-closure and transverse-closure, was discovered during the water entry process. The closure depth, the maximum diameter and the diameter of tail-cavity increase dramatically with larger velocity, and are also affected by the specific weight.