Cavitation in an Oscillatory Oil Squeeze Film

Abstract

This paper records observed features of cavitation arising in an oscillatory oil squeeze film. In the experimental apparatus, two nondeformable surfaces contained the oil film. The square upper surface oscillated, normally to the oil film, at any frequency between 5 and 50 Hz. A transparent lower surface together with a viewing and synchronising system enabled cavitation bubble patterns in the oil film to be observed and photographed at any point in the oscillatory cycle. Three different behavioral regimes (designated 1, 2, and 3) have been observed, each characterized by the method of forming cavitation bubbles together with particular features in the oil film pressure, thickness and bubble extent-time cycle. Descriptions are given of the salient features of each regime, and the transition from one to another. The paper contains photographs of cavitation bubble patterns at important points in the typical oscillatory cycles together with their location in the oil film pressure and thickness time histories.