Wind Load Characteristics of Semi-Planing Typed High-Speed Vehicle With Changing Body Attitude

Abstract In this work, the aim is to understand the wind load characteristics of a semiplaning high-speed vehicle moving straight ahead in calm water. The authors have developed a simulator to evaluate the performance of various types of vehicles, and the focus of this study is on a semiplaning highspeed vehicle with a box-shaped hull that has a flat bottom and flaps at the front and rear. Previous studies have shown that evaluating the effect of wind on a vehicle is important because its attitude changes significantly depending on its navigation speed. Therefore, in this study, computational fluid dynamics (CFD) simulations were performed via OpenFOAM to obtain the wind load characteristics of the vehicle depending on its attitude, and wind tunnel tests were conducted to obtain validation data on the loads and the wind fields around the vehicle. The wind load coefficients and the wind fields from the CFD simulations agreed well with the wind tunnel test results. This study revealed that there are components of the wind load coefficients that differ significantly depending on the attitude. In particular, the yaw moment may act in the opposite direction depending on the attitude when the vehicle is subjected to crosswinds. That is, as the vehicle’s operating speed changes, it experiences a moment that alters its running direction, potentially leading to unstable motion. The accuracy of the evaluation can be improved by providing the simulator with appropriate wind load coefficients for changing the vehicle attitude.