Dynamic Response of a Moored Semisubmersible in Short-Crested Wave Fields


Department of Civil Engineering,Sharif University of Technology


Wind generated sea states are more accurately modeled by short-crested wave fields. Whether or not these short-crested waves can induce larger response amplitudes in floating offshore structures is of great concern to offshore engineers. In this paper, the hydrodynamics of a moored semisubmersible in short-crested wave fields is investigated. Morison-based motion equations with nonlinear damping terms are used to analyze the dynamic behavior of the structure. A generalized three-parameter short-crested wave field is introduced as the incident wave. The effect of transverse phase lag, wave propagation angle and different ratios of in-line and transverse wave numbers are studied on the force and response amplitudes of the floating structure. Finally, the results are compared to that of the long-crested wave fields and critical cases are specified.