Proposal of a Groove Cavitator on a Supercavitation Propeller

Abstract

A supercavitation propeller (SCP) that has high efficiency under supercavitating condition is expected as one of the most suitable propulsors for a high-speed vessel. To design a SCP with higher efficiency, a thinner cavity is recommended. However, less supercavitation sometimes occur contrary to the designer's expectation, thus the thrust becomes less than the design value and the efficiency becomes lower. In order to obtain the predicted thrust and high efficiency, it is necessary to let stable cavitation occur from the leading edge as predicted by theory. The authors propose a new cavitator that stimulates cavitation by a thin groove near the leading edge on the backside surface. Through the present comparative tests between propellers with and without the cavitator, it was clarified that the proposed cavitator is effective in stimulating and stabilizing a supercavity, and that it increases the propeller efficiency.