Effects of yaw angle on hydrodynamic performance for an oblique planing hull

Abstract

High-speed small crafts are extensively used in various environments. However, these planing vessels are prone to motion instabilities, particularly during turning and course-changing maneuvers. Understanding their behavior under a fixed yaw angle is crucial in the early design stages. This paper presents a numerical study to evaluate the influence of yaw angle on the hydrodynamic performance of high-speed planing hulls. The results indicate that the yaw angle has a significant influence on the hull’s running attitudes, as well as hydrodynamic forces and moments. At large yaw angles, air is drawn into the roll-down side, resulting in a small dynamic wetted surface area in high-speed cases. A negative pressure region is observed under high-speed conditions, with asymmetric conditions accentuating (mitigating) this negative pressure region on the roll-down (roll-up) sides. The peaks of sectional lift and resistance are typically observed near the stagnation line in most cases. The sectional sway force is more pronounced behind the center of gravity when the planing speed is slightly above the critical velocity of the trim angle, resulting in a positive yaw moment and suggesting a trend toward a reduction in the yaw angle. It is evident that the aerodynamic resistance on the transom surface is considerable in high-speed cases. The understanding of these phenomena is crucial for the effectiveness of high-speed small craft designs.