Experimental study on vegetation flexibility as control parameter for wave damping and velocity structure
Experimental study on vegetation flexibility as control parameter for wave damping and velocity structure
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DOI：
10.1016/j.coastaleng.2020.103648
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发表时间：
2020-04
影响因子：
4.4
通讯作者：
T. V. Veelen;T. P. Fairchild;D. Reeve;H. Karunarathna
中科院分区：
文献类型：
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作者：
T. V. Veelen;T. P. Fairchild;D. Reeve;H. Karunarathna
植被可以通过阻挡来袭的波浪来帮助海岸防御。然而，先前的研究表明，植物物种之间的衰减差异很大。植物的柔韧性是一种通常被忽略的力学性质，但在盐沼上的灌木和草之间有很大的差异。因此，我们提出了一个实验室波浪水槽与人工植被，不同的灵活性只有一个实验研究。我们测量了刚性和柔性盐沼植被周围的波衰减和水粒子速度。波测量使用一系列的仪表和粒子图像测速（PIV）被用来测量水粒子速度的时空变化在x-z平面周围的植被。我们的研究结果表明，灵活的植被衰减波高达70%，低于刚性植被由于灵活的植物摇摆。此外，我们发现，刚性植被修改的速度结构，而灵活的植被没有。具体地说，在波传播的方向上的平均电流周围的树冠和水平粒子速度被放大直接上方的树冠。这些结果表明，植物的灵活性是一个关键的参数，在波浪-植被相互作用，控制波阻尼和速度结构。
Vegetation can contribute to coastal defence by damping incoming waves. However, prior studies have shown that attenuation varies greatly among plant species. Plant flexibility is a mechanical property that is commonly omitted, but varies considerably between shrubs and grasses on salt marshes. Therefore, we present an experimental study in a laboratory wave flume with artificial vegetation that differs in flexibility only. We measured wave attenuation and water particle velocities around rigid and flexible salt marsh vegetation. Waves were measured using a series of gauges and Particle Image Velocimetry (PIV) was used to measure spatio-temporal variations of water particle velocities in the x-z plane around the vegetation. Our results show that flexible vegetation attenuates waves up to 70% less than rigid vegetation due to swaying of flexible plants. Furthermore, we find that rigid vegetation modifies the velocity structure, whereas flexible vegetation does not. Specifically, a mean current in the direction of wave propagation develops around the canopy and the horizontal particle velocities are amplified directly above the canopy. These results indicate that plant flexibility is a key parameter in the wave-vegetation interaction that controls wave damping and velocity structure.