Experimental investigation versus numerical simulation of the dynamic response of a moored floating structure to waves

A combined experimental/numerical investigation of a moored floating structure response to incoming waves is presented. The floating structure consists of three bodies, equipped with fenders, joined by elastic cables. The system is also moored to the seabed with eight mooring lines. This corresponds to an actual configuration of a floating structure used for ships and submarines in special docking operations. The dynamic wave response is investigated by performing experiments in a towing tank equipped with a wave maker. Experimental results are compared with numerical simulations in regular and irregular waves, showing a good agreement. The predicted time histories of pitch, heave and surge motions of the three-body structure and of the mooring line forces bear very satisfactorily the experimental results in regular head waves. The case of irregular waves is also encouraging, since the statistics of the response is correctly kept up to the fourth-order statistical moments. This confirms that the theoretical model proposed in this paper is a suitable tool to predict the actual behaviour of a complex moored structure at sea.