Investigation of Wave-Structure Interaction in Floating Breakwaters

Pontoon breakwaters are one of the most common types of floating breakwaters. Floating breakwaters are mainly used for wave reflection and energy dissipation. Wave energy loss by turbulence in the current is caused by the transmission of waves through the structure. Also, since waves break on the upper side of the structure, wave energy decay occurs. The efficiency of floating breakwaters is generally presented by a factor that is called transmission coefficient. The transmission coefficient is a ratio of the transmission wave height to the incident wave. This study tries to investigate the performance of floating breakwaters. For a realistic assessment, the Caspian sea’s hydrodynamic conditions are used. Also, two types of floating pontoon breakwaters have been modeled. This research aims to evaluate the performance sensitivity of breakwaters in relation to their geometry and wave characteristics like wave height and period. Hydrodynamic conditions are simulated by ANSYS AQWA finite element software. At first, a rectangular model (No.۱) was simulated by hydrostatic analysis and time history analysis by applying average ۲۰-year wave conditions and then using time history analysis by applying the critical wave characteristics. Then, the same procedure was performed on a trapezoidal model (No.۲). According to the results, the transmission coefficient increases with increasing the wave period, but the increase in wave height has no effect on the breakwater efficiency.

Keywords:

breakwater , wave , wave period , ANSYS AQWA