6DOF motion and Cavity Dynamics of a Ventilated Super-cavitating Vehicle with Control Fins

Flow fields around a super-cavitating vehicle with control fins in ventilated cavity and its six-degrees-of-freedom (6DOF) motion were investigated by computational fluid dynamics (CFD) analysis. SNUFOAM, a CFD program based on an open-source CFD toolkit and specialized for naval hydrodynamics, was used in this study. A mixture fluid-based cavitation model and k - ω SST model were employed for the analysis of turbulent multiphase flow with liquid water, vapor, and non-condensable gas. Convection and diffusion terms were discretized by the second order upwind and central differencing scheme, respectively. The geometry of interest was a super-cavitating vehicle consisted of a cone-shaped nose, cylindrical main body, and four control fins near the tail. A cavitator and ventilation holes for injecting non-condensable gas were located at the nose of the vehicle. To accommodate the motion of deploying fins, a layering mesh technique was employed, while a mesh morphing technique was used for the motion of the vehicle body. Two different control fin operations, which are deploying and deflecting fins, were applied and the effects of injecting non-condensable gas were also examined.