Bow and Stern Control Surface’s Effectiveness and Influence on Supercavity

The numerical model of supercavitating flow field was established based on multiphase model, cavitation model, and turbulence model. The model was employed to simulate the supercavitation flow for the supercavitating vehicle with two types of control surfaces: bow rudder and stern rudder. The influence of both control surfaces on the supercavity shape and rudder effectiveness is compared under the different rudder angles (0-12°), and the effectiveness and the influences on supercavities of bow rudder and stern rudder were explored according to the numerical research results. From the research results, the following conclusions can be drawn: (1) the bow rudders have stable rudder effectiveness and available rudder angle, and the bow rudders also have significant influence on supercavities’ shape. (2) By contrast with the bow rudder, stern rudders’ effectiveness is difficult to predict accurately, and the phenomenon of stalling will occur when stern rudders’ rudder angle exceeds 6°; however, there is almost no influence of stern rudders on supercavities. (3) The bow and stern rudders joint control mode must take the influence on supercavities’ shape and the accuracy of control force’s forecasting into account at the same time. The research is helpful to the optimizing of superhigh-speed vehicles and the design of control modes.

INVESTIGATION OF UNDERWATER MOTION PARAMETERS FOR INERT CONICAL MODELS

This paper considers high-speed underwater motion of an axisymmetric inert conical model in a supercavitation flow regime. Experimental data on the model velocity variation with distance in water are obtained. Based on these data, a computational method, which is developed to determine the model velocity, is validated. A comparison of the calculated and experimental results obtained in a hydroballistic track shows that, in the first approximation, the motion of the model in a supercavitating flow regime can be considered as the motion of a flat disk having a mass and being streamed around at the developed cavitation directed normally to the surface. Experimental contours of supercaverns are compared with those calculated using the known computational methodology. The conditions ensuring supercavitation motion of the inert conical models in water are determined. As a result, the extended range of the horizontal motion is calculated for the inert conical models moving in a supercavitation regime under water at a depth up to 200 m at given initial velocity, depth of the trajectory location, and model parameters. It is found that reducing of a cavitator radius does not always have a positive effect on the range of the inert model motion.