Three-dimensional simulation and evaluation of the hydrodynamic effects of stern wedges on the performance and stability of high-speed planing monohull craft

Abstract

This study analyzed the hydrodynamics of a high-speed monohull craft model through increasing its longitudinal stability to improve its performance. First, a high-speed planing monohull craft was simulated using computational fluid dynamics. The free surface was analyzed using a three-dimensional volume of a fluid model. The modeled craft with two degrees of freedom was solved using the overset technique for dynamic mesh. For verification, the results of this study were compared with those of an experimental test performed in the laboratory. Accordingly, it was found that the experimental and numerical results were in good agreement. The modeled craft also showed longitudinal instability at a speed of 8 m/s (equal to the speed of sailing). To eliminate this longitudinal instability and subsequently improve the longitudinal performance, craft stern wedges with triangular sections were added in three modes to examine their effects on the resistance and stability of the craft using computational fluid dynamics. Moreover, the results showed that due to the reduction of trim to about 42%, the longitudinal instability was removed at a constant speed, and as a result the longitudinal performance of the craft increased while the total resistance decreased.