Integral space-time scales in turbulent wall flows
Integral space-time scales in turbulent wall flows
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DOI：
10.1063/1.1586273
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发表时间：
2003-06
影响因子：
4.6
通讯作者：
M. Quadrio;P. Luchini
中科院分区：
文献类型：
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作者：
M. Quadrio;P. Luchini
通过对Navier-Stokes方程的直接数值模拟，计算了湍流通道中速度波动的时空相关性。通过研究纵向壁面剪切应力的自相关R（ξ,τ）作为流向和时间分离的函数，可以描述和量化使用（人工）周期边界条件时计算域的有限范围的影响。从时空数据中计算出一个与传统积分尺度相似的时间尺度，但在统计上与湍流结构的寿命时间有关。对流速度，定义为ξ，τ平面上的方向，其中自相关在极小的时间延迟下达到最大值，计算为与壁面距离的函数，并与文献中可用的数据进行比较。基于自相关性，泰勒假设被验证的准确性被定量评估。最后，空间d的效果。
A direct numerical simulation of the Navier–Stokes equations is used to compute the space–time correlations of velocity fluctuations in a turbulent channel flow. By examining the autocorrelation R(ξ,τ) of the longitudinal wall shear-stress as a function of the streamwise and temporal separations, the effects of the limited extent of the computational domain when (artificial) periodic boundary conditions are used can be described and quantified. A time scale similar to the conventional integral scale but statistically related to the life time of the turbulent structures is computed from spatio-temporal data. The convection velocity, defined as the direction in the ξ,τ plane where the autocorrelations have their maximum at vanishingly small time delay, is computed as a function of the distance from the wall, and compared with the data available in the literature. Based on autocorrelations, the accuracy within which Taylor’s hypothesis is verified is quantitatively assessed. Last, the effect of the spatial d...