Applicability of Frozen-Viscosity Models of Unsteady Wall Shear Stress
Applicability of Frozen-Viscosity Models of Unsteady Wall Shear Stress
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DOI：
10.1061/(asce)hy.1943-7900.0000930
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发表时间：
2015
影响因子：
2.4
通讯作者：
A. Vardy;Jim Brown;S. He;C. Ariyaratne;S. Gorji
中科院分区：
文献类型：
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作者：
A. Vardy;Jim Brown;S. He;C. Ariyaratne;S. Gorji
使用详细的计算流体动力学（CFD）模拟评估了支撑管道和通道瞬态流中非定常壁面剪应力理论模型的一类重要理论模型的假设冻结粘度条件的有效性。在分析大规模管网中的瞬变流时，不可避免地需要壁应力的近似一维（1D）{x，t}模型，因为使用高阶分析方法在经济上是不可行的。然而，各种模型的基础从未严格建立。本文表明，第一作者开发的常用方法在光滑壁流动的情况下是有缺陷的，尽管它对于粗糙壁流动更合理。评估过程是针对一个特殊的，但重要的，非定常流的情况下，即，从最初的稳定湍流均匀加速。首先，详细的预测，从一个有效的CFD方法被用来获得基线解决方案…
AbstractThe validity of assumed frozen-viscosity conditions underpinning an important class of theoretical models of unsteady wall shear stress in transient flows in pipes and channels is assessed using detailed computational fluid dynamics (CFD) simulations. The need for approximate one-dimensional (1D){x,t} models of the wall stress is unavoidable in analyses of transient flows in extensive pipe networks because it would be economically impracticable to use higher order methods of analysis. However, the bases of the various models have never been established rigorously. It is shown herein that a commonly used approach developed by the first authors is flawed in the case of smooth-wall flows although it is more plausible for rough-wall flows. The assessment process is undertaken for a particular, but important, unsteady flow case, namely, a uniform acceleration from an initially steady turbulent flow. First, detailed predictions from a validated CFD method are used to derive baseline solutions with which...