High-Speed Stereo-Observations of Violent Vibrations Associated with Three Types of Cavitation

Abstract

In order to improve the reliability of high-speed hydraulic machinery, detailed behavior of the violent vibrations appearing on a typically low-drag Eppler foil is systematically observed by means of high-speed stereophotography. We can clearly observe the following three types of violent vibrations : (i) the vibrations resulting from a singly-attached cavity, usually arising at a higher incidence α_i, (ii) ones resulting from large travelling bubbles arising at a lower incidence, (iii) a mixture of these two types.