Representing plants as rigid cylinders in experiments and models
Representing plants as rigid cylinders in experiments and models
复制标题
DOI：
10.1016/j.advwatres.2015.10.004
复制
发表时间：
2016-07
影响因子：
4.7
通讯作者：
Andrés Vargas‐Luna;A. Crosato;G. Calvani;W. Uijttewaal
中科院分区：
文献类型：
--
作者：
Andrés Vargas‐Luna;A. Crosato;G. Calvani;W. Uijttewaal
模拟水系统的形态适应通常需要考虑植物对水和沉积物动力学的影响。尽管真实植物的大小、形状和灵活性各不相同，但物理和数值模型需要以易于量化的示意图来表示植被。常见的方法将植物表示为刚性圆柱体，但这些图式再现植被对形态动力学过程的影响的能力从未被系统分析过。这项工作的重点是在实验室测试和数值模拟中将植物表示为刚性圆柱体的后果。新的实验表明，对于植物和刚性圆柱体来说，随着元素雷诺数的增加，流动阻力会降低。河岸上的圆柱体可以定性地再现植被对河道宽度和河岸相关过程的影响。数值模拟的比较回顾表明，巴普蒂斯特的方法将河床剪应力和植被阻力的贡献相加，低估了真实河流稀疏植被内的河床侵蚀，高估了实验室实验中的平均流速。这是由于假设植物之间的流动均匀以及高估了浸没率的作用。
Simulating the morphological adaptation of water systems often requires including the effects of plants on water and sediment dynamics. Physical and numerical models need representing vegetation in a schematic easily-quantifiable way despite the variety of sizes, shapes and flexibility of real plants. Common approaches represent plants as rigid cylinders, but the ability of these schematizations to reproduce the effects of vegetation on morphodynamic processes has never been analyzed systematically. This work focuses on the consequences of representing plants as rigid cylinders in laboratory tests and numerical simulations. New experiments show that the flow resistance decreases for increasing element Reynolds numbers for both plants and rigid cylinders. Cylinders on river banks can qualitatively reproduce vegetation effects on channel width and bank-related processes. A comparative review of numerical simulations shows that Baptist's method that sums the contribution of bed shear stress and vegetation drag, underestimates bed erosion within sparse vegetation in real rivers and overestimates the mean flow velocity in laboratory experiments. This is due to assuming uniform flow among plants and to an overestimation of the role of the submergence ratio.