Estimating drag coefficient for arrays of rigid cylinders representing emergent vegetation
Estimating drag coefficient for arrays of rigid cylinders representing emergent vegetation
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DOI：
10.1080/00221686.2018.1494050
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发表时间：
2018-09
影响因子：
2.3
通讯作者：
F. Sonnenwald;V. Stovin;I. Guymer
中科院分区：
文献类型：
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作者：
F. Sonnenwald;V. Stovin;I. Guymer
摘要植被引起的水流阻力在水利工程中有着广泛的应用。本文评估了几个实用的工程函数，用于估计刚性圆柱体的体积阻力系数()，这些刚性圆柱体通常用于表示新兴植被。许多求值函数都基于与描述粘性和惯性效应的两个系数相关的Ergan导出的表达式。提出了一种基于圆柱体直径(D)和固体体积分数(φ)的Ergan系数的重新参数化方法。估计与以前研究中的一系列实验数据进行了比较。在较低的φ和较高的柱面雷诺数()下，所有函数都进行了合理的估计。在φ较高的情况下，他们通常会低估。利用这里提出的重新参数化的估计比使用其他评估函数的估计更好地匹配实验数据，特别是在低φ和低的情况下。
ABSTRACT Flow resistance due to vegetation is of interest for a wide variety of hydraulic engineering applications. This note evaluates several practical engineering functions for estimating bulk drag coefficient () for arrays of rigid cylinders, which are commonly used to represent emergent vegetation. Many of the evaluated functions are based on an Ergun-derived expression that relates to two coefficients, describing viscous and inertial effects. A re-parametrization of the Ergun coefficients based on cylinder diameter (d) and solid volume fraction (φ) is presented. Estimates of are compared to a range of experimental data from previous studies. All functions reasonably estimate at low φ and high cylinder Reynolds numbers (). At higher φ they typically underestimate . Estimates of utilizing the re-parametrization presented here match the experimental data better than estimates of made using the other functions evaluated, particularly at low φ and low .