A sectional method to estimate the transmission coefficients of a new type pile-supported permeable breakwater

This article investigates the transmission coefficient of a novel pile-supported permeable breakwater featuring inclined porous plates under regular waves. To analyze the transmission coefficient, we propose a sectional method that involves multiplying the transmission coefficients of three distinct sections: the upper retaining wall and porous plates, the horizontal platform, and the piles. The calculation employs the eigenfunction expansion method and empirical formula for pile-supported breakwaters. This method is applicable for water levels that fall between the upper and lower edges of the horizontal platform. The analytical results are compared with experimental tests and show good agreement. Further analysis reveals that the transmission coefficient is significantly influenced by the increasing length of the horizontal platform. Moreover, it is observed that the effect of porosity epsilon is not particularly noticeable when epsilon > 20%.