Abstract
Wave absorbing mounds are constructed on the harbor sides of the breakwaters for reduction of reflection of long-period waves. Armor units of wave absorbing mounds constructed on the harbor sides have to be stable for wave overtopping. In this study, the stability of the armor units of wave absorbing mounds constructed on harbor sides of sloping top breakwaters and rectangular ones for wave overtopping are compared by hydraulic model experiments. The armor units of wave absorbing mounds with the sloping top breakwaters are more unstable than with the rectangular ones. When the crest of the wave absorbing mound is higher than water surface, armor units are more unstable than when the crest is the same height as the water surface. But in this case, the transmission coefficient of overtopping wave is smaller than in case of submerged mounds.
