RESISTANCE COEFFICIENTS FOR INBANK AND OVERBANK FLOW.
RESISTANCE COEFFICIENTS FOR INBANK AND OVERBANK FLOW.
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DOI：
10.1680/iwtme.1999.31426
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发表时间：
1999-06
期刊：
影响因子：
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通讯作者：
W. Myers;D. Knight;J. Lyness;J. Cassells;F. Brown
中科院分区：
文献类型：
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作者：
W. Myers;D. Knight;J. Lyness;J. Cassells;F. Brown
阻力系数是根据在实验室和现场条件下对复合和简单通道形状进行的测量得出的。实验室数据是使用英国洪水渠道设施（FCF）测量的，这是一个大型实验复合渠道。 FCF 的边界粗糙度条件包括具有光滑和杆状粗糙洪泛平原的光滑主河道，以及具有光滑和杆状粗糙洪泛平原的沙质主河道河床。洪泛区的粗糙度由 25 毫米表面穿透的定位销杆组成。还获得了简单渠道的数据，以便通过将流量限制在主渠道进行比较。现场数据是从当地河流河段获得的，该河段已被重建以形成对称的复合横截面。现场和实验室数据可以计算一定深度范围内复合截面的粗糙度系数。此外，速度测量可以计算流量，从而可以分别计算主河道和洪泛区的粗糙度系数。光滑的简单河道阻力系数被发现符合已知的关系，而移动床简单河道粗糙度系数随着深度的增加而增加到最大值，响应于沙丘尺寸的增加。表面穿透粗糙度产生随着深度不断增加的粗糙度系数。随着相对粗糙度的降低，自然银行内数据表现出更多的分散性，并且随着深度的增加而呈现减小的趋势。复合截面的粗糙度系数表现出复杂的行为，并且受到表面穿透漫滩杆粗糙度的强烈影响。光滑的主河道粗糙度系数受到洪泛平原粗糙度的强烈影响，而沙床的引入使得主河道数据在很大程度上独立于洪泛平原粗糙度。河流数据通常显示比实验室河道更大的值，但趋势与平滑边界数据相似。差异是由于河流横截面上存在向内倾斜的洪泛平原。
Resistance coefficients have been presented from measurements taken in compound and simple channel shapes in both laboratory and field conditions. Laboratory data were measured using the UK Flood Channel Facility (FCF), a large-scale experimental compound channel. Boundary roughness conditions in the FCF included smooth main channel with both smooth and rod-roughened flood plains, and a sand main channel bed with both smooth and rod-roughened flood plains. The flood plain roughness consisted of 25 mm surface-penetrating dowel rods. Data were also obtained for simple channels for comparison by confining flow to the main channel. The field data were obtained from a local river reach which has been reconstructed to form a symmetrical compound cross-section. The field and laboratory data enabled calculation of roughness coefficients for compound sections at a range of depths. In addition, velocity measurements enabled calculation of discharges and hence roughness coefficients for main channel and flood plains separately. Smooth simple channel resistance coefficients were found to conform to known relationships, while mobile bed simple channel roughness coefficients increased with depth to a maximum, responding to increasing dune size. Surface-penetrating roughness produced continuously increasing roughness coefficient with depth. Natural inbank data exhibit more scatter and followed a decreasing trend with depth, as relative roughness decreased. Roughness coefficients for the compound sections exhibited complex behaviour and were strongly influenced by the surface-penetrating flood plain rod roughness. Smooth main channel roughness coefficients were strongly influenced by flood plain roughness, while the introduction of a sand bed rendered the main channel data largely independent of flood plain roughness. River data display generally larger values than the laboratory channel, but trends are similar to the smooth boundary data. Differences are due to the presence of inwardly sloping flood plains on the river cross-section.