Prediction of the compressible stage slamming force on rigid and elastic systems impacting on the water surface

In this paper some models focusing on hydrodynamic and elastic forces arisi ng during the impact of rigid and elastic systems on the water surface are investigated. In particular, the supersonic compressible stage of the impac t is considered by modelling the slamming phenomenon through the Skalk-Feit acoustic approximation. The dynamic equations of the dropping system are c oupled to those of the fluid and a nonlinear fluid-solid interaction proble m is stated. General relationships between the body's shape, slamming force and body motion are determined. These equations are applied to the wedge w ater entry cases, and a closed-form expression for the maximum hydrodynamic force is found. Moreover the theoretical correlation between the hydrodyna mic force and the body geometry allows us to control the inverse problem an d the shape associated to a constant slamming force is determined. Due to some simplifications allowed in the supersonic compressible impact, the results of the hydrodynamic analysis hold in closed form. This permits us to focus on the basic result of the paper addressed to a systematic corr elation between hydrodynamic and elastic maximum forces in terms of some ch aracteristic dimensionless quantities involved in fluid-solid interaction. In particular, 'critical conditions' corresponding to those hydorelastic pa rameters combinations are investigated, leading to severe elastic response of the impacting system.