Heave motion response of a circular cylinder with the dual damping plates

A damping plate attached to the floating structure has a distinct advantage in reducing the motion response of a floating structure by increasing the added mass and damping. Analytical and experimental studies were carried out to investigate the heave motion response of a floating cylinder according to the characteristics of dual damping plates (DDPs), such as submergence depth and radius ratio. An analytical method using a Matched Eigenfunction Expansion Method (MEEM) was developed for solving the radiation problem by a heaving circular cylinder with DDPs in the context of linear potential theory. To confirm the present analytical solutions, a series of experiments for heave motion responses was conducted in a two-dimensional wave tank in regular waves with varying wave frequencies. The analytical results were in good agreement with the experimental results, and the heave motion response of the cylinder was decreased considerably within the region of heave resonance frequency by installation of the proposed DDPs. By using the predictive tools requiring less calculation time, the effect of damping plates as motion reduction devices for spar-type offshore platforms can be assessed for various combinations of parameters such as the number, size, and location of damping plates at the concept design stage.