3-d calculation for multiple floating bodies in proximity using wave interaction theory

With increasing the number of floating bodies, the calculation for wave-body interactions becomes formidable with the direct panel method. In such a case, the wave interaction theory may be used. However, there is a mathematical limitation in applying the theory that each interacting body must be far enough apart from the other bodies. Nevertheless, in practice, the wave interaction theory has been used successfully even for a case where the separation distance between the bodies is virtually zero. In this paper, numerical investigation is made on the practical applicability of the wave interaction theory by considering four identical box-shaped bodies as a practical example and comparing computed results with correct ones obtained by the higher-order boundary element method. It is shown that the wave force in the horizontal direction can be obtained favorably by the interaction theory even if the separation distance between the bodies is very small, but it is not the case for the wave force in the vertical direction. Discussion on this somewhat strange phenomenon is also made.