Determination of the drag coefficients of emergent and just submerged willows
Determination of the drag coefficients of emergent and just submerged willows
复制标题
挺水柳树和初沉柳树阻力系数的测定
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
F. Nestmann
中科院分区：
文献类型：
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作者：
S. Wunder;B. Lehmann;F. Nestmann
本文给出了滩地植被水流阻力和阻力系数的计算结果。根据文献综述，大多数关于流与木本植被相互作用的研究都是基于实验室实验，其中植被是理想化的，具有很高的抽象性。然而，植被的抵抗行为取决于许多自然参数，如弯曲刚度、水流中的收缩方式、叶片化程度和振动行为。此外，还必须观察到由于目前的力量而导致的植被要素的不同形状。本文给出了三种柳树的阻力系数随水流条件的变化，以及植物的柔韧性和叶理对投影植物面积的影响，从而对阻力系数的影响。结果表明，由于阻力系数是不同物理效应的结果，因此区分有叶和无叶状态是非常重要的。
This paper presents results regarding the flow resistance and the drag coefficient of floodplain vegetation. According to the literature review, most of the investigations concerning the interaction between flow and woody vegetation are based on laboratory experiments where the vegetation is idealized with a high level of abstraction. However, the vegetation's resistance behaviour depends on many natural parameters, such as the flexural rigidity, the manner of contraction in the current, the degree of foliation and the vibration behaviour. Furthermore the varying shape of the vegetation elements due to the current forces has to be observed. The drag coefficients of three kinds of willow species depending on the flow conditions and the effect of the plants flexibility and foliation on the projected plant area and thus on the drag coefficient are presented in this paper. The results show that it is very important to distinguish between leafy and leafless condition as the drag coefficient is a result of different physical effects.