EVOLUTION OF THE CAVITATION BUBBLE DRIVEN BY PERIODIC PRESSURE

Cavitation generally occurs in liquid flows if the local pressure drops below the vapor pressure. This phenomenon can be observed in a wide variety of hydrodynamic systems, such as pumps, nozzles, injectors, marine propellers, hydrofoils, and underwater bodies. Owing to its unsteady nature, cavitation affects fluid power systems and components in various ways, which are usually undesirable. For example efficiency of a system is reduced due to cavitation and vibrations as well as noise level of a system are increased. In this work, we investigate a bubbly flow in a venturi nozzle. The bubbles are assumed to be spherical with variable radius R. The evolution of bubble radius R is governed by Rayleigh-Plesset equation. This equation coupled with the continuity and momentum equations are solved numerically using Runge-Kutta fourth order method with adaptive step size. The evolution of the mixture velocity, pressure, void fraction and bubble radius has been analyzed. Two regimes of behavior have been observed.