Water entry of a wedge by hydroelastic orthotropic plate theory

Water entry of a hull with wedge-shaped cross sections is analyzed. The sti ffened platings between two transverse girders on each side of the keel are separately modeled. Orthotropic plate theory is used. The effect of struct ural vibrations on the fluid flow is incorporated by solving the two-dimens ional Laplace equation in the cross-sectional fluid domain by a generalized Wagner's theory. The coupling with the plate theory provides three-dimensi onal flow effects. The theory is validated by comparison with full-scale ex periments and drop tests. The importance of global ship accelerations is po inted out. Hydrodynamic and structural error sources are discussed. Systema tic studies on the importance of hydroelasticity as a function of deadrise angle and impact velocity are presented. This can be related to the ratio b etween the wetting time of the structure and the greatest wet natural perio d of the stiffened plating. This ratio is proportional to the deadrise angl e and inversely proportional to the Impact velocity. A small ratio means th at hydroelasticity is important and a large ratio means that hydroelasticit y is not important.