Developing an Approximation of a Natural, Rough Gravel Riverbed Both Physically and Numerically
Developing an Approximation of a Natural, Rough Gravel Riverbed Both Physically and Numerically
复制标题
从物理和数值上建立天然粗糙砾石河床的近似值
DOI：
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
B. Bockelmann
中科院分区：
文献类型：
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作者：
A. Stubbs;T. Stoesser;B. Bockelmann
近床和孔隙空间湍流开始被理解使用新技术和直接数值模拟（DNS）和大涡模拟（LES）技术的进展。然而，在许多计算研究中使用的河床几何形状仍然过于简单。因此，本研究提出了一个砾石河床矩阵的人工表示的发展，以及它如何近似于一个自然河床的评估。砾石河床基质的物理模型是120毫米深，300毫米宽，2.048米长的铸造丙烯酸制造。此外，创建物理模型的数值近似并用于分析。人工河床的孔隙基质的孔隙度和孔隙比与天然砾石河床的孔隙基质相当。人工河床的表面颗粒的直径被发现变化较小，与较少的不规则性，比天然砾石河床，但它们的正态分布类似于天然河床。功率谱密度函数表明，人工河床的粗糙度，这是远远低于在自然界中发现的。因此，液压阻力和摩擦系数都将低于期望值。这些研究结果表明，在这项研究中已经开发的新方法可以提供的砾石床表面的物理和数值近似值，这是一个天然砾石河床与低表面粗糙度，减少颗粒大小的变化，和典型的颗粒分布和孔隙度。
Near-bed and pore space turbulent flows are beginning to be understood using new technologies and advances in direct numerical simulation (DNS) and large-eddy simulation (LES) techniques. However, the riverbed geometry that is used in many computational studies remains overly simplistic. Thus, this study presents the development of an artificial representation of a gravel riverbed matrix, and the assessment of how well it approximates a natural riverbed. A physical model of a gravel riverbed matrix that was 120 mm deep, 300 mm wide, and 2.048 m long was manufactured from cast acrylic. Additionally, a numerical approximation of the physical model was created and used for analysis. The pore matrix of the artificial riverbed was found to be comparable to that of a natural gravel riverbed in terms of its porosity and void ratio. The diameters of the artificial riverbed’s surface particles were found to vary less, with fewer irregularities, than those found for natural gravel riverbeds; yet, they were normally distributed similarly to natural riverbeds. A power spectral density function showed that the artificial riverbed exhibited a degree of roughness that was much lower than that found in nature. Thus, the hydraulic resistance and friction factor will both be lower than desired. These findings suggest that the novel methods that have been developed in this study can offer both the physical and numerical approximation of a gravel bed surface that is comparable to a natural gravel riverbed with low surface roughness, reduced particle size variance, and typical particle distribution and porosity.
影响因子：
2.4
作者：
G. Blois;G. S. Sambrook Smith;J. Best;R. Hardy;J. Lead
通讯作者：
G. Blois;G. S. Sambrook Smith;J. Best;R. Hardy;J. Lead