A hybrid potential theory for predicting the motions of a moored ship induced by large-scaled tsunami

In our previous study, we proposed a practical numerical simulation method on moored ship motions induced by tsunami, which was attained by a connection between a tsunami profile by the tsunami simulation and a velocity potential around the ship. The velocity potential was derived from the tsunami profile, which was able to express and calculate not only the surface elevation and currents but also the exciting force of the ship simultaneously. In the previous method, the tsunami surface elevation was reproduced well, however the currents were not. In this paper, we investigate the difference between both the currents, and propose a hybrid potential theory to improve the accuracy on the connection. In this proposed method, simultaneous equations for several parameters to coincide with each other are newly established by considering an equivalent infinite long quay wall for substituting a pair of predominant incident and reflected tsunami waves for the original tsunami wave profile. It has been confirmed that the ship motions and the mooring loads are influenced by the evaluation method on the velocity potential calculated by the tsunami profile.