The response of a semisubmersible model under focused wave groups: Experimental investigation

In recent years, extreme wave events have occurred more frequently than have been predicted using theoretical methods. It is, therefore, a requirement to investigate the impact of these events on coastal and offshore structures. This paper reports on results of an experimental investigation into the interaction between unidirectional waves and a horizontally moored semisubmersible model. The target crest height was created at a focal point and time using the focused wave technique. Different values of wave steepness were tested in order to ascertain the nonlinear effects on the quality of waves generated by a piston-type wavemaker. The measured crest height was in good agreement with the theoretical one within 4% relative error. The magnitudes of heave and pitch motions of the model were found to increase as the wave steepness increased. Overall, the paper contributes towards establishing the application of focused wave technique to floating offshore platforms