Experimental and numerical investigation on cloud cavitating flow around an axisymmetric projectile near the wall with emphasis on the analysis of local cavity shedding

In this paper, the mechanisms of cavitating flow around an axisymmetric projectile near a wall with local cloud cavity shedding are analyzed using experimental and numerical methods. Several experiments are designed to observe the evolution of cavity around an axisymmetric projectile near a wall underwater with cavitation number sigma = 0.45. Numerical simulations using the large eddy simulation (LES) approach, Kunz cavitation model, and volume of fluid (VOF) method are established in an open-source code OpenFOAM framework to present more information on the flow structure. The shape and length of the cavity are in good agreement with the experimental observation, which guarantees the accuracy of the numerical methods. The characteristics of cavitation around the axisymmetric projectile near the wall are reported, and the wall effect is briefly analyzed according to the experimental observations and the details obtained from the numerical results. Local cavity shedding, which increases the instability of cavity periodic shedding, is observed to be induced by the combination of the vortex structure, jet at the cavity closure, and special cavity shape on the projectile near the wall.