Analysis on hydrodynamic properties of trimaran barge with forward speed in frequency domain

To investigate the hydrodynamic properties of the trimaran barge with forward speed in the wave,and the effects of the velocity and the environmental factors on the response amplitude operators(RAOs)of the trimaran barge,the potential theory and the wave radiation/diffraction theory were employed to analyze the wave exciting forces and the hydrodynamic coefficients.The motions equations of the trimaran barge were solved and RAOs of six degrees of freedom obtained by the general hydrodynamic calculation procedure AQWA.The curves of RAOs with regular wave frequency under different working conditions,such as various speeds,water depths and encounter wave angles,were obtained.The results show that the surge RAOs go down with the increase of the forward speed.However,the pitch peak increases with the increase of the forward speed.The water depth has obvious effects on RAOs,namely the shallow water can decrease the heave RAOs,and the pitch peak frequency goes down with the decrease of the water depth.When the ratio of water depth to the draft is bigger than 20,the water depth can be considered infinite.The encounter angle has big influence on RAOs of each degree of freedom.It is better for the motions that the trimaran barge navigates in the bow sea and head sea.