Interaction between a cavitation bubble and shear flow

Abstract

The deformation of a cavitation bubble in shear and extensional flows is studied numerically. The Navier–Stokes equations are solved to observe the three-dimensional behaviour of the bubble as it grows and collapses. During the collapse phase of the bubble, two re-entrant jets are observed on two sides of the bubble. The re-entrant jets are not the result of interaction with a solid wall or free surface; rather, they are formed due to interaction of the bubble with the background flow. Effects of the viscosity, surface tension and shear rate on the formation and strength of re-entrant jets are investigated. Re-entrant jets with enough strength break up the bubble into smaller bubbles. Post-processing and analysis of the results are done to cast the disturbance by the bubble on the liquid velocity field in terms of spherical harmonics. It is found that quadrupole moments are created in addition to the monopole source.