Hydroelastic Analysis of Hard Chine Sections Entering Water - Observations for Use in Preliminary Design Stage

Abstract

Wing-in ground effect (WIG) vehicles and planing hulls are exposed to unsteady, high magnitude hydrodynamic forces as their bow enters water. The resulting forces can lead to structural damage and uncomfortable riding conditions. This paper aims to provide deeper understanding on the influence of structural flexibility throughout the water entry process of a hard-chine section. A finite volume method (FVM) based flexible fluid-structure interaction (FFSI) model is used to solve multi-physics. Quantitative comparisons are made between experimental and computational data. Simulations demonstrate that structural responses can attenuate the pressure acting on the body of hard-chine sections impinging water with deadrise angles of 10deg, 20deg, and 30deg. However, they cannot affect that of a section with deadrise angle of 45deg since its pressure distribution pattern is different. It is shown that the impact speed has an important role in hydroelastic response while the sectional Young's modulus affects impact pressures and resulting equivalent stresses. The former increases under the increase of Young's modulus. The latter may increase when the impact speed is low and decreases when the impact speed is high. It is concluded that the results presented may be useful for preliminary design.