SPH modeling of wave interaction with reshaped and non-reshaped berm breakwaters with permeable layers

Abstract

A berm breakwater may reshape during storms while its hydraulic performance depends on its reshaping status. Some experimental studies have been done to evaluate berm recession and to suggest the final reshaped breakwater section. Some numerical models have also been developed in the recent years especially by taking into account the permeability of breakwater layers and these powerful models cab be utilized efficiently to simulate wave interaction with permeable reshaping breakwaters. In this study, a numerical model based on SPH technique is developed to compare the hydraulic performance of a non-reshaped with a reshaped breakwater. To validate this model, wave transmissions from a permeable submerged breakwater as well as wave penetration through a reshaping breakwater are modeled and the calculated wave profile as well as wave pressure inside the porous breakwater are compared with the recorded data in available experimental studies. Then, by modeling both reshaped and non-reshaped breakwaters with different porosities, different hydraulic responses such as wave reflection, dissipation, transmission and run-up are calculated for these cases. It has been shown that the hydraulic performance of a berm breakwater depends on both its reshaping status and permeability of armor layer. In addition, either modeling the reshaped geometry or neglecting the permeability of armor layer results in overestimated responses such as overestimated wave run-up and overtopping. Therefore, it is necessary to model a reshaping section with actual permeability to evaluate hydraulic performance of a berm breakwater accurately. However, for initial design purposes, a reshaped impermeable breakwater can be applied conservatively.