Bed-Load Motion at High Shear Stress: Dune Washout and Plane-Bed Flow
Bed-Load Motion at High Shear Stress: Dune Washout and Plane-Bed Flow
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高剪切应力下的床荷运动：沙丘冲刷和平面床流
DOI：
10.1061/(asce)0733-9429(1995)121:3(267
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发表时间：
1995
影响因子：
2.4
通讯作者：
K. Wilson
中科院分区：
文献类型：
--
作者：
F. Nnadi;K. Wilson
在高压管道系统中研究了高剪应力下泥沙运动。床材包括三种砂和胶木。当无量纲剪应力趋于统一时，陡度陡然消失。这种行为表明从床型向上平面床型的突然转变，而不是逐渐转变。结果表明，这种类型的流动比传统的粗糙边界具有更大的摩擦阻力。还确定的是，摩擦特性的形式制度不能单独表示在无因次剪切应力方面。观察到的行为还表明，作为一种固体输运机制，沙波可能比平面上床流更有效。
Sediment motion at high shear stress is investigated in a pressurized-conduit system. The bed materials include three sands and bakelite. As the dimensionless shear stress was increased toward unity, the steepness of the bedforms disappeared abruptly. This behavior is indicative of a sudden shift from the bedform regime to the upper-plane-bed regime, not a gradual transition. The results for the upper-plane-bed regime reveal that this type of flow has a larger frictional resistance than that of a conventional rough boundary. Also determined is that frictional characteristics of the bedform regime cannot be expressed solely in terms of dimensionless shear stress. The observed behavior also suggests that, as a solid-transport mechanism, sand waves may be more efficient than upper-plane-bed flow.