Wave-Current Interaction Effects on Moored Tankers in High Seas
A tanker moored in irregular head waves in combination with or without current performs large amplitude low frequency surge motions. Due to low frequency motions in combination with or without the current field the second order wave drift forces will be a function of the tanker velocities.By means of 3-D potential theory the quadratic transfer function of the wave drift force for zero speed and low forward speed were computed. By means of the gradient-method the transfer function of the constant speed dependent wave drift force and the wave drift damping coefficient. were derived. The transfer function of the wave drift damping coefficient is compared with the results of model tests.By means of the obtained results time-domain computations on the low frequency surge motions in irregular waves with and without current were carried out. The results of the computed low frequency motions were compared with the results of model tests. The time-domain computations are based on the wave train registrations as were adjusted for the model tests.