Performance Comparison of Bow and Stern Rudder for High-Speed Supercavitating Vehicles

To predict the hydrodynamic characteristics and supercavity shape of supercavitation flows, the numerical model including VOF, cavitation model, and turbulence models is presented and validated by a well-established empirical correlation. The numerical method is then employed to simulate the high-speed supercavitating vehicles with two different types of control surfaces: bow rudders and stern rudders. The hydrodynamic characteristics and influences on the supercavity are compared. By contrast with the stern rudder, the bow rudder with the same wetted area is capable of generating a larger control force and moment. Also, the bow rudder introduces a considerable deformation to the forepart of the supercavity, while the stern rudder provides a negligible influence on the supercavity before it. In addition, the bow rudder is fully wetted, and the lift force only changes with the rudder angle. However, the stern rudder is partly wetted; the lift force is not only determined by the rudder angle but also related to the actual wetted status.