Abstract
Sheet to cloud cavitation over a wedge is investigated using numerical simulations performed at a Reynolds number Re = 200,000 and cavitation numbers ranging from σ = 1.44 to σ = 2.18. The multiphase fluid is described using a homogeneous mixture model, and the governing equations are the compressible Navier Stokes equations for the liquid/vapor mixture along with a transport equation for the vapor mass fraction. The numerical method, based on a characteristic based filtering approach for shock and interface capturing, is first validated by comparing with the experimental measurements, showing acceptable agreement. A systematic parametric investigation of sheet to cloud cavitation phenomenon for different cavitation numbers is then carried out. The two primary mechanisms known to destabilize the sheet cavity viz. the re-entrant jet mechanism and the condensation shock mechanism are captured in the simulations. Two cases in the condensation shock regime and two cases in the re-entrant jet regime are investigated in this paper; the similarities and differences between the two regimes are elucidated. The results presented here are part of an ongoing investigation on identifying the precise physical conditions that lead to the transition between the re-entrant jet and condensation shock mechanisms, a clear knowledge of which is yet to be elucidated.
