Numerical Investigation on the Ventilated Supercavity around a Body under Free Surface Effect

Reducing vessel resistance by using ventilated cavities has been a highly researched topic in the marine industry. There is limited literature on ventilated supercavities near the free surface, which indicates that their dynamic behavior is more complex than conventional ventilated cavities due to the effect of the free surface. This paper employs numerical simulations to study the dynamic behavior of the ventilated supercavity, taking into account the effect of the free surface. Numerical simulations can predict gas leakage behaviors, cavity geometry, and internal flow structures. The influence of the free surface shortens the length of the ventilated cavity and increases the diameter. The presence of the free surface mainly changes the vertical velocity distribution between the free surface and the cavity. The results show that there are two typical gas leakage mechanisms under different immersion depths: twin-vortex tube leakage mode and re-entrant jet leakage mode. The internal flow field of ventilated supercavity is classified into three regions: the internal boundary layer, the ventilation influence region, and the reverse flow region. As the distance between the free surface and the ventilated supercavity decreases, the ventilated supercavity is affected by both the free surface effect and the gravity effect.

Automated summary

This paper investigates the dynamic behavior of ventilated supercavities considering the effect of the free surface through numerical simulations. The presence of the free surface affects the length and diameter of the ventilated cavity, as well as the vertical velocity distribution between the free surface and the cavity. Two typical gas leakage mechanisms, namely the twin-vortex tube leakage mode and the re-entrant jet leakage mode, were observed at different immersion depths. The internal flow field of the ventilated supercavity can be classified into three regions: the internal boundary layer, the ventilation influence region, and the reverse flow region. The ventilated supercavity is influenced by both the free surface effect and the gravity effect as the distance between the free surface and the cavity decreases.