Abstract
A breakwater with retreated parapet is sometimes employed in order to reduce horizontal wave force and wave overtopping. This study proposes a new retreated parapet that has a flared cross section. The parapet has a deep circular cross section which overturns an incoming flow motion to offshore. The effect of this flared parapet on reducing wave overtopping was investigated through hydraulic experiments. The experiment was carried out with two dimensional wave tank. Numerical simulation with using Cadmas-surf was also conducted to investigate the characteristics of hydraulic pressures and foeces on the parapet. This study clears that the retreated parapet with flared cross section reduces the wave overtopping more effectively than a upright parapet which is conventionally employed on coastal structures. The flared parapet on the rear side has smaller horizontal force than that on the front side. Furthermore, the downward force acts on the flared parapet, and the force becomes larger when the paraper retreats to the rear side.
