Prediction of Hydroelastic Behavior of a Very Large Floating Structure in Waves and Current

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Theoretical and experimental investigations have been performed with the purpose of establishing a method of prediction for the hydroelastic behavior of a very large floating structure in waves and current (or equivalently advancing with forward speed in waves). The results of the research are summarized as follows :1. A boundary integral equation method was developed to predict the hydroelastic response of a very large floating structure in waves and current A potential flow theory is employed with low current speed assumption. This permits the velocity potential be expanded in a perturbation series of forward speed. Retaining the leading-order terms in the forward speed, the boundary-value problem is reduced to two sets of integral equations which only contain the zero speed Green's function. The solution can be obtained efficiently by applying the boundary element technique which is well-developed for zero speed case.2. The theory was applied to predict the hydroelastic behavior of a circular plate advancing with forward speed in waves. It was shown that the hydroelastic response of the plate is significantly influenced by the presence of small forward speed. Its effect is more significant for the bending strain than the displacement. The approximate prediction taking only account of Doppler's effect is found to underestimate the forward speed effect.3. In order to validate the theoretical approach wave tank tests have been performed using a small scale model of a very large floating structure in waves (without current). Agreement was found to be satisfactory between theory and experiment, thus confirming the validity of the theoretical prediction.