An Overset Grid Approach to Linear Wave-Structure Interaction

A finite-difference based approach to wave-structure interaction is reported that employs the overset approach to grid generation. A two-dimensional code that utilizes the Overture C++ library has been developed to solve the linear radiation problem for a floating body of arbitrary form. This software implementation has been validated by performing time-domain simulations to evaluate the dynamic forces applied to a half-submerged cylinder and a rectangular barge in response to a prescribed motion. A Gaussian displacement is used to introduce a range of wave frequencies, thereby allowing the measurement of the body response over the frequency range of interest. The radiation added-mass and damping coefficients of both bodies have been evaluated and compared to exact analytical solutions. The numerical and analytical results show good agreement when the modes of excitation and response are the same. The cross-coupled results are in qualitative agreement, but show some quantitative variations that may be related to slight differences in the fluid domain geometry. For both the cylinder and the barge, the effects of bottom slope on the coefficients are found to be minimal.