Numerical investigation of drag reduction by heat-enhanced cavitation

This paper numerically investigated the possibility of creating supercavitation through an artificially induced increase in the surface temperature of the underwater vehicle. Firstly, in order to consider the influence of thermomechanical effect on the cavitation process, the Zwart-Gerber-Belamri (ZGB) cavitation model was modified. By comparing with the experimental results, the accuracy of the modified model was validated. Secondly, the modified cavitation model was used to simulate the cavitating flows over a hemisphere cylinder body whose surface was heated to different temperatures. With the aid of CFD software ANSYS CFX, the variation of the bubble volume fraction and skin friction drag of the hemisphere cylinder at different cavitation numbers and heating temperatures were obtained and analyzed. The results show that the generation and development of cavity can be promoted by using the heating method. In this way, the friction resistance on underwater vehicle surfaces can be reduced effectively. There exists an optimal heating temperature to make the cavitation bubbles fully developed and cover the whole outside surface of underwater vehicle. By this means, the friction resistance on underwater vehicle surfaces can be reduced effectively, and the speed of vehicle can increase accordingly. (C) 2014 Elsevier Ltd. All rights reserved.