Hydroelastic Sloshing Induced Impact with Entrapped Air

摘要

Hydroelasticity may be important for sloshing induced impacts in a closed container. Impacts are often characterized by entrapment of air. Local pressures are then influenced by the compressibility of air. These effects are confirmed by experiments on sloshing in a partially filled rectangular tank where the upper part of a vertical wall is made flexible by inserting a thin aluminium plate. Measurements show significant strains in the elastic plate, as well as an influence of the structural deformation on the impact pressure. A theoretical model is developed to solve for the impact flow when an air cavity exists in a corner. The flow caused by the impact is solved by using a vortex distribution along the wetted part of the tank roof and the enclosed air cavity. This representation enables an accurate numerical description of the impact, by relying to a large degree on analytical expressions. The inflow condition to the tank roof impact is based on experimental findings. The presented numerical approach has a clear advantage relative to traditional CFD methods, which have difficulties in the prediction of impact pressures. The hydroelastic response of the aluminium plate is found by application of beam theory, analytical expressions for added mass and results from the impact flow analysis.