Flow resistance dynamics in step‐pool stream channels: 1. Large woody debris and controls on total resistance
Flow resistance dynamics in step‐pool stream channels: 1. Large woody debris and controls on total resistance
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阶梯池河道中的流阻动力学：1.大型木质碎屑和总阻力控制
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
E. Wohl
中科院分区：
文献类型：
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作者：
A. Wilcox;E. Wohl
通过实验室水槽的物理模型研究了阶梯-水池通道中的流阻动力学。对影响阶梯-水池通道流阻的变量进行了操作，以测量各种大型木质残体（LWD）配置、阶梯、颗粒、流量和坡度对总流阻的影响。这需要近400个水槽运行，组织成一系列析因实验。方差析因分析表明，台阶、颗粒和随钻测井之间存在显著的双向和三向交互作用，说明了这些通道中流动阻力的复杂性。台阶和随钻测井之间的相互作用导致随钻测井台阶比无随钻测井台阶的流动阻力大得多。随钻测井位置促成了这些相互作用，因此，位于台阶边缘附近的随钻测井碎片（类似于天然渠道中的台阶形成碎屑）增加了台阶的有效高度，并产生了比位于台阶踏板上游更远的碎片更高的流动阻力。阶梯几何形状和随钻测井密度和方向也有非常显着的影响流动阻力。流动阻力动力学和床面粗糙度配置的阻力效应强烈依赖于流量;流量对阻力具有非常显著的主要影响，并与所有其他变量具有非常显著的相互作用。
Flow resistance dynamics in step‐pool channels were investigated through physical modeling using a laboratory flume. Variables contributing to flow resistance in step‐pool channels were manipulated in order to measure the effects of various large woody debris (LWD) configurations, steps, grains, discharge, and slope on total flow resistance. This entailed nearly 400 flume runs, organized into a series of factorial experiments. Factorial analyses of variance indicated significant two‐way and three‐way interaction effects between steps, grains, and LWD, illustrating the complexity of flow resistance in these channels. Interactions between steps and LWD resulted in substantially greater flow resistance for steps with LWD than for steps lacking LWD. LWD position contributed to these interactions, whereby LWD pieces located near the lip of steps, analogous to step‐forming debris in natural channels, increased the effective height of steps and created substantially higher flow resistance than pieces located farther upstream on step treads. Step geometry and LWD density and orientation also had highly significant effects on flow resistance. Flow resistance dynamics and the resistance effect of bed roughness configurations were strongly discharge‐dependent; discharge had both highly significant main effects on resistance and highly significant interactions with all other variables.