Nonlinear behavior of wave resonances in moonpool with a recess under wave actions

Abstract

Nonlinear wave resonance in moonpool with a recess under wave actions is studied by using CFD simulations based on OpenFOAM® package. Compared to the rectangular moonpool, the influence of free surface nonlinearity plays an important role in the wave resonance in the recess moonpool. Harmonic analysis indicates that the higher-order harmonic induced sloshing-mode resonance even approaches the same magnitude as the first-order harmonic induced piston-mode motion. The superposition between them also leads to extreme free surface oscillation in the recess moonpool. A peak appears in the total horizontal wave forces by the higher-order harmonic induced sloshing resonance due to the anti-symmetric mode. In a word, the free surface nonlinearity is an indispensable factor in the response of fluid resonance in moonpool with recess configurations.