Abstract Large (km-scale) mangrove forests can provide protection to shorelines and near-coast structures during extreme coastal flood events, including tsunamis and tropical cyclones. However, little is known about the effects of mangroves with a modest cross-shore thickness (∼10 – 50 m), on flow hydrodynamics and resulting inland pressures and forces on near-coast structures. We constructed a 1:16 geometric-scale physical model of a Rhizophora mangle (red mangrove) fringe with modest cross-shore thickness to measure the effects of a mangrove forest’s cross-shore thickness on wave attenuation and subsequent load reduction on near-coast structures, idealized during experiments with an array of cubes. Three configurations, one baseline with zero mangroves and two with mangrove cross-shore thicknesses corresponding to prototype-scale forest widths of 8.2 m and 19.0 m, were considered in front of an array of idealized slab-on-grade residential buildings. Transient wave conditions with varying incident parameters (wave amplitude, wave representative time scale, water level/mangrove emergence, and presence of a background current) were considered. Water surface elevations, water velocities, cross-shore forces, and pressures measured near and against the building array indicate that mangroves affected inland flow hydrodynamics and forces. The presence of mangroves was associated with elevated water levels and reduced peak velocities between the mangroves and inland structures. Increasing the mangrove cross-shore thickness reduced the cross-shore force on a structure by 11% to 65% compared to the baseline case without mangroves. The force reduction by the mangrove configurations varied with incident wave representative time scale; waves with longer representative time scales required larger cross-shore thicknesses to provide similar force reductions to those observed for shorter waves. Further investigation into a wider range of mangrove cross-shore thicknesses, trunk densities, and wave conditions is needed to inform engineering performance of natural and nature-based features for resilient coastal design.

中文翻译：

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中型红树林对建筑环境中流动流体动力学、压力和载荷影响的物理模型研究

摘要 大型（公里级）红树林可以在极端沿海洪水事件（包括海啸和热带气旋）期间为海岸线和近海岸结构提供保护。然而，关于具有适度跨岸厚度（~10-50 m）的红树林对流动流体动力学以及由此产生的内陆压力和对近海岸结构的作用力的影响知之甚少。我们构建了一个 1:16 几何比例的具有适度跨海岸厚度的红树林红树林边缘物理模型，以测量红树林跨海岸厚度对波浪衰减和随后对近海岸结构的负载减少的影响，在使用一系列立方体进行实验时理想化。三种配置，一个零红树林基线和两个红树林跨岸厚度对应于 8.2 m 和 19.0 m 的原型森林宽度，被考虑在一系列理想化的楼板住宅建筑前。考虑了具有不同入射参数（波幅、波代表时间尺度、水位/红树林出现和背景电流的存在）的瞬态波条件。在建筑物阵列附近和附近测量的水面高度、水流速度、跨岸力和压力表明红树林影响了内陆流动的流体动力学和力。红树林的存在与水位升高和红树林与内陆结构之间的峰值速度降低有关。与没有红树林的基线情况相比，增加红树林跨海岸厚度可使结构上的跨海岸力降低 11% 至 65%。红树林配置引起的力减少随入射波代表时间尺度变化；具有较长代表性时间尺度的波浪需要更大的跨海岸厚度，以提供与观察到的较短波浪相似的力减少。需要对更广泛的红树林跨海岸厚度、树干密度和波浪条件进行进一步调查，以便为弹性海岸设计提供自然和基于自然特征的工程性能。具有较长代表性时间尺度的波浪需要更大的跨海岸厚度，以提供与观察到的较短波浪相似的力减少。需要对更广泛的红树林跨海岸厚度、树干密度和波浪条件进行进一步调查，以告知弹性海岸设计的自然和基于自然特征的工程性能。具有较长代表性时间尺度的波浪需要更大的跨海岸厚度，以提供与观察到的较短波浪相似的力减少。需要对更广泛的红树林跨海岸厚度、树干密度和波浪条件进行进一步调查，以告知弹性海岸设计的自然和基于自然特征的工程性能。