Water Entry of a Flexible Wedge: The Correlation between Instantaneous Jet Root, Pressure History and Structural Response*

Slamming plays a crucial role in the design process of high-speed craft. Using a vertically falling wedge drop experiment to model vertical impacts, the hydrodynamic loads and resulting structural response can be attributed to the loss in momentum of the penetrating body. As a result, a wave is formed, and the point of attachment to the hull is called the spray root. In this talk, a discussion of the results from the experimental investigation of water entry of a flexible wedge with a 20-degree deadrise angle will be presented. Hydrodynamic pressure and kinematic motions of the wedge are measured. The deflection of the thin bottom plate is measured using stereoscopic digital image correlation. High-speed cameras are used to capture the spray root. The instantaneous spray root positions on the flexible wedge are compared to its corresponding pressure distribution at each time increment. Results were compared with a rigid wedge drop experiment. Results show that evolution of spray root on a flexible wedge is slightly delayed compared to the rigid one. In fact, the jet has to travel additional distance on the wedge due to the curvature in flexible bottom that is caused by the fluid-structure interaction.