THREE-DIMENSIONAL NUMERICAL ANALYSIS OF MOTION OF A TOWED FLOATING CAISSON UNDER REGULAR WAVES

Abstract

 A three-dimensional numerical analysis was conducted using a three-dimensional coupled fluidstructure-sediment-seabed interaction model (FS3M) to investigate the motion of a floating caisson towed along a straight line under regular waves. Numerical results showed that the heave and the pitch of the caisson tended to fluctuate with the same period as the apparent incident wave period observed from the caisson. Furthermore, the amplitude of the heave increased when the apparent wave period matched the natural period of the heave. The natural period of the pitch was affected by towlines; thus, the amplitude of the pitch increased when the apparent wave period matched the natural period of the pitch considering the towlines. The time-averaged value of the tension force acting on the towline increased with increasing the incident wave height and during heave and pitch resonances.