A computational study of wall friction and turbulence dynamics in accelerating pipe flows
A computational study of wall friction and turbulence dynamics in accelerating pipe flows
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DOI：
10.1016/j.compfluid.2007.09.001
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发表时间：
2008-07
影响因子：
2.8
通讯作者：
S. He;C. Ariyaratne;A. Vardy
中科院分区：
文献类型：
--
作者：
S. He;C. Ariyaratne;A. Vardy
使用从稳态均匀加速的光滑管道中的湍流 CFD 模型来研究湍流和惯性对壁面剪应力的影响。低雷诺数 k-ε 湍流模型与有限体积/有限差分离散方案结合使用。结果表明，壁面剪应力最初超过了相应的准稳态值，这归因于惯性原因。此后，壁面剪应力显示出低于准稳态值，因为惯性效应被湍流对流动变化的响应延迟的累积影响所抵消。研究了流动行为对几何形状、流体特性、雷诺数和加速度的依赖性，并显示其与基于湍流产生时间尺度的无量纲参数有很好的相关性。初始过冲的持续时间以及过冲和下冲的幅度在高雷诺数时比在低雷诺数时更小。
A CFD model of turbulent flow in a smooth pipe accelerating uniformly from steady state is used to study the influence of turbulence and inertia on wall shear stresses. A low-Reynolds-number k–ε turbulence model is used in conjunction with a finite volume/finite difference discretization scheme. It is shown that the wall shear stress initially overshoots the corresponding quasi-steady value and this is attributed to inertial causes. Thereafter, the wall shear stress is shown to undershoot the quasi-steady value because inertial effects are more than counterbalanced by the cumulative influence of delays in the response of turbulence to flow changes. The dependence of the flow behaviour on the geometry, the fluid properties, the Reynolds number and the acceleration is studied and is shown to correlate well with a non-dimensional parameter based on the turbulence production timescale. The durations of the initial overshoots and the amplitudes of the overshoots and undershoots are smaller at high Reynolds numbers than at low ones.