Abstract In the present study, gravity wave interaction with a wave attenuating system (WAS) comprised of a series of surface piercing thin vertical porous plates fixed on a fully submerged rigid pontoon is analyzed. For the wave past porous barriers, a quadratic pressure drop is considered to account for the energy dissipation due to changes in wave steepness. A numerical model based on iterative multi-domain boundary element method is developed under the assumption of a small amplitude water wave theory. The scattering coefficients (reflection and transmission) and wave force coefficients (horizontal, vertical and moments) are computed for different wave and structural parameters such as the number of plates, relative plate width, the relative depth of submergence, plate porosities, and relative wave steepness. The results demonstrate that with the creation of trap zones through multiple porous plates on a submerged rigid pontoon, it is possible to reduce wave transmission by 60–70%. For optimum performance across all water depths, it is suggested for the WAS to have 1 ≤ B/h ≤ 1.5 and h1/h ≤ 0.3. Also, interestingly there is a 25–30% reduction in the vertical wave forces which reduces the load acting on the ancillary equipment. The WAS is found to perform well for porosity μ = 20 % , above which the wave transmission increases gradually. The study results can be useful in the cost-effective design of this type of special wave barrier for a range of coastal engineering field applications.

中文翻译：

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重力波与波衰减系统的相互作用

摘要 在本研究中，分析了重力波与波浪衰减系统 (WAS) 的相互作用，该系统由一系列固定在完全淹没的刚性浮筒上的表面穿透薄垂直多孔板组成。对于通过多孔屏障的波，二次压降被认为是由于波陡度变化引起的能量耗散。在小幅水波理论的假设下，建立了基于迭代多域边界元方法的数值模型。计算不同波浪和结构参数的散射系数（反射和透射）和波浪力系数（水平、垂直和力矩），如板块数量、相对板块宽度、相对淹没深度、板块孔隙度和相对波浪陡度。结果表明，通过在水下刚性浮筒上通过多个多孔板创建陷阱区，可以将波传输减少 60-70%。为了在所有水深上获得最佳性能，建议 WAS 具有 1 ≤ B/h ≤ 1.5 和 h1/h ≤ 0.3。此外，有趣的是，垂直波浪力减少了 25-30%，从而减少了作用在辅助设备上的负载。发现 WAS 在孔隙度 μ = 20 % 时表现良好，高于此值，波传输逐渐增加。研究结果可用于为一系列沿海工程领域应用经济有效地设计此类特殊波浪屏障。为了在所有水深上获得最佳性能，建议 WAS 具有 1 ≤ B/h ≤ 1.5 和 h1/h ≤ 0.3。此外，有趣的是，垂直波浪力减少了 25-30%，从而减少了作用在辅助设备上的负载。发现 WAS 在孔隙度 μ = 20 % 时表现良好，高于此值，波传输逐渐增加。研究结果可用于为一系列沿海工程领域应用经济有效地设计此类特殊波浪屏障。为了在所有水深上获得最佳性能，建议 WAS 具有 1 ≤ B/h ≤ 1.5 和 h1/h ≤ 0.3。此外，有趣的是，垂直波浪力减少了 25-30%，从而减少了作用在辅助设备上的负载。发现 WAS 在孔隙度 μ = 20 % 时表现良好，高于此值，波传输逐渐增加。研究结果可用于为一系列沿海工程领域应用经济有效地设计此类特殊波浪屏障。