Do wooden pile breakwaters work for community-based coastal protection?
Do wooden pile breakwaters work for community-based coastal protection?
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DOI：
10.1007/s11852-020-00749-5
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发表时间：
2020-05
影响因子：
2.1
通讯作者：
H. Takagi;Shoya Sekiguchi;N. Thao;Thamnoon Rasmeemasmuang
中科院分区：
文献类型：
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作者：
H. Takagi;Shoya Sekiguchi;N. Thao;Thamnoon Rasmeemasmuang
在发展中国家，用木桩保护海岸可能是一种低成本和环保的对策选择，当地社区甚至个人都可以很容易地实施。然而，这些桩在现实环境中的有效性还有待科学证明，而且到目前为止，还没有关于这种临时海岸保护的既定设计指南。这项研究的重点是越南的Phan Thiet市，那里的当地人正求助于木桩来缓解紧挨着他们房子前面的严重的海岸侵蚀。采用不规则波三维水动力模型对木桩周围和桩间复杂的波浪机理和水动力进行了研究。入射和反射波之间复杂的相互作用机制不能用普通的2D数值模型或数学分析来充分评估，这表明了使用3D流体动力学模型的好处。木桩的性能可以用两个标准来简单地评估：波浪爬升和弯曲应力。结果表明，在越南某侵蚀严重的海滩上设置木桩，可以在一定程度上减少岸坡上的波浪爬升。波浪抬高的减少是由于波浪在桩上的部分反射所触发的湍流和振荡的产生，将水流分流到不同的方向。实例研究表明，向海方向的波浪压力约为岸边方向的一半。然而，由于陡峭海岸的强烈反射，负方向的压力可能会瞬间增加。本文讨论了这种最先进的计算流体力学模型是否可以为木桩防波堤的评估做出贡献。
In developing countries, coastal protection with wooden piles may be a low-cost and eco-friendly countermeasure option that can be readily implemented by local communities or even individuals. However, the effectiveness of these piles in a realistic environment has yet to be scientifically proven, and there have been no established design guidelines for this type of improvised coastal protection to date. This study focuses on Phan Thiet City, Vietnam, where local people are resorting to wooden piles to mitigate severe coastal erosion immediately in front of their houses. A 3D hydrodynamic modelling with irregular waves is applied to evaluate complex wave mechanisms and hydrodynamics around and between wooden piles. The complicated interaction mechanisms between incident and reflected waves cannot be adequately evaluated using a common 2D numerical model or mathematical analysis, demonstrating the benefit of using a 3D hydrodynamic model. The performance of wooden piles are simply assessed using two criteria: wave run-up and bending stress. The result shows that wooden piles installed at a severely eroded beach in Vietnam can reduce wave run-up on the beach slope to some extent. The reduction in wave run-up occurs because of the creation of turbulence and oscillation triggered by the partial reflection of waves on the piles, diverting water flows into various directions. A case study shows that wave pressure in the seaward direction is about a half of that in the shoreward direction. However, the pressure in the negative direction can be instantaneously increased due to a significant reflection from a steep shore. This paper discusses whether such a state-of-the art computational fluid dynamics model can contribute to the assessment of wooden pile breakwaters.