KINETIC CHARACTERISTICS AND HYDRODYNAMIC FORCES ON SEMI-PLANING TYPED HIGH-SPEED VEHICLE BY MODEL TEST AND RANS SIMULATION

This paper aims to understand the kinetic characteristics and the hydrodynamic forces on a semi-planing typed high-speed vehicle during moving straight in calm water and in head waves. One of the features of this vehicle is considerable variation in its attitude due to the changes in the resistance value and propulsion performance associated with the change in a Froude number of the vehicle, and no reliable method has been established to evaluate this feature in advance. Therefore, we conducted free/captive towing tests at Froude numbers ranging from 0.03 to 1.8 using a scale model of the vehicle. The results show that the vehicle can move straight stably without unstable vibration even at high Froude numbers. In addition, we performed 3D unsteady RANS (Reynolds-Averaged Navier-Stokes equation) simulations for the vehicle with Froude numbers of 0.9, 1.2, and 1.8 in calm water and found that the RANS simulation could reproduce the experimental results relatively well with respect to the vehicle's attitude, the drag coefficient, and the free surface shape around the vehicle.