Large-eddy simulation of flow around a sphere: Comparing cavitating and non-cavitating conditions

In this work partial and supercavitation over a sphere at a constant Reynolds number of 1.5×106 and a broad range of cavitation numbers (0.36<σ<1) was examined. Large eddy simulation (LES) and Sauer mass transfer model were used to simulate the dynamic and unsteadycavitation around the sphere. Also, the compressive volume of fluid (VOF) method is used to track the cavity interface. The two-phase flow solver of the OpenFOAM package, intephaseChangeFoam is employed. Largeeddy simulation of cavitating flow over the sphere iscompared with the non-cavitating flow at the same Reynolds number. This work provides a thorough understanding of the fluid dynamic characteristics of the sphere cavitation such as turbulent kinetic energy, pressure, streamlines and boundary layer. Also, detailedanalyses of the instantaneous cavity leading edge and separation point location, vortex shedding, streamwise velocity fluctuation and evolution of the cavity are reported. We report that cavitation suppresses instability in the near wake region and delays the three-dimensional breakdown of the vortices. The volume fraction contours of the cavity cloud obtained from the numericalsimulations are compared with the experimental data at the same working condition with a suitable quantitative accuracy

Keywords:

Unsteady Cavitation , Sphere , Large eddy simulation (LES) , Wake , Vortical structure