International Symposium on Transport Phenomena and Dynamics of Rotating Machinery
10-15 Apr 2016
Sheraton Waikiki Hotel, Honolulu, USA
AbstractVentilated cavitation occurs as an extremely complicated problem if the free surface is close to the cavity boundary around the high-speed underwater vehicle. The cavitating flow around a blunt axisymmetric body very near the free surface is investigated in the present paper. The typical experiment is carried out in a launching system based on an SHPB device, and the numerical scheme is established on the basis of large eddy simulation (LES) and volume of fraction (VOF) methods. Unsteady behaviors such as air injection and shedding of the cloud cavity were obtained, and good agreement was achieved between the numerical and experimental results. The distinctions of evolution features between the cavities on the up and down sides are presented and analyzed. Firstly, strong injection of non-condensable air occurs and changes the media property inside the cavity, which makes the cavity much larger and more stable. Furthermore, because of the small distance between the vehicle and the free surface, the re-entry jet generated in the upper part is very thin and cannot cut off the main cavity clearly, which induces that the upper part of the cavity is approximately unchanged after the growth stage and no shedding phenomenon occurs inside it.