A Submerged Mound Type Long-Period Wave Absorbing Structure

In many ports, it has been reported that long-period waves cause trouble in cargo handling. As a countermeasure to this, a wave absorbing mound installed on the harbor-side of the breakwater has been proposed. However, because of the low wave absorbing performance of such conventional structures, the required width to absorb the long-period waves becomes more than 30m. It is important therefore to reduce the size of the structure to apply to various site conditions. In this study, a submerged mound type long-period wave absorbing structure is proposed. A series of hydraulic model experiments was carried out to evaluate the wave absorbing performance and stability characteristics of the armor units against wave overtopping. Throughout this study, it became clear that submerged structures display a higher wave absorbing performance compared with those of conventional structures. Moreover, a prediction formula for the stability number for Tetrapods used in the Hudson formula is proposed.