High-fidelity computational fluid–structure interaction and physical analysis of flexible plate slamming

One- and two-way fluid–structure interaction (FSI) studies are conducted for vertical and oblique flexible plate slamming, compared with experiments, and used to diagnose the hydroelasticity interactions between the plate deflections and the spray root physics. The simulations are performed for one vertical and two oblique conditions, and these are selected from the experimental test matrix using the hydroelasticity parameter and show significant hydroelastic effects. Computational fluid dynamics (CFD) and CFD/FSI simulations are performed with the unsteady Reynolds-averaged Navier–Stokes equations solver CFDShip-Iowa V4.5 with the level-set method for the free-surface tracking. A nonlinear modal expansion with Newmark integration solves the structural dynamics. Numerical results are in good agreement with the experimental trends for the effects of plate thickness, velocity ratio, and Froude number. This paper introduces the use of an extended Bernoulli equation for stagnation flows in a constantly accelerated coordinate system to investigate and explain the spray root pressure difference between the one-way and two-way results (rigid and elastic plate, respectively). The analysis shows that the structural deflection and its spatial gradient interact with the spray root producing a difference in the normal force between the rigid and elastic plate. Finally, the conservation of energy is discussed. The results suggest that a larger power is required during the slam of the elastic plate, which is mostly absorbed by the structural deflection. The errors achieved in the energy conservation are reasonable and suggest that the FSI approach is accurate.