Nonlinear Hydrodynamic Pressures on Ship Hulls in Waves

A two-dimensional time-domain nonlinear strip theory is developed for predicting nonlinear hydrodynamic pressures and associated ship motions in large amplitude regular waves.The problem is solved with time-domain free-surface Green function and source distributions on instantaneous wetted hull surface in incident waves.Improved numerical model and scheme are employed to avoid divergence and enhance efficiency during simulation procedures.The emphasis is placed on the nonlinear hydrodynamic pressures on instantaneous body surface under incident waves and the consistence of ship motions and hydrodynamic forces that are achieved with a differential numerical scheme.The drawbacks of linear strip theory in predicting hydrodynamic pressures are pointed out with the comparisons of predicted and model test results.The nonlinear phenomena of hydrodynamic pressures with wave heights and the distributions of the positive and negative hydrodynamic pressures are illustrated with predicted results of a Wigley ship.The primary calculation shows encouraging prospect for further development of the theory and its application.