Refined cf relation for turbulent channels and consequences for high-Re experiments
Refined cf relation for turbulent channels and consequences for high-Re experiments
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DOI：
10.1088/0169-5983/41/2/021405
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发表时间：
2009-04
影响因子：
1.5
通讯作者：
E. Zanoun;H. Nagib;F. Durst
中科院分区：
文献类型：
--
作者：
E. Zanoun;H. Nagib;F. Durst
关于槽道湍流测量的准确性，特别是表面摩擦结果的测量，已经引起越来越多的关注。在本研究中，两种不同的方法，即平均流向压力梯度（PG）和油膜干涉（OFI），被用来估计壁面摩擦关系，cf = f（Rem），充分发展的湍流平面通道流在很宽的雷诺数范围。通道表面摩擦数据，然后拟合到众所周知的对数摩擦定律，提供出色的协议与平均速度分布的对数定律的常数的值。本文提出了一个修正的对数摩阻关系式，它采用Zanoun等人最近工作中的对数摩阻关系式中的常数，与我们的摩阻结果和文献中的数据吻合较好（2003 Phys. Fluids 15 3079-89，2005第四届传热、流体力学和热力学国际会议，HEAT 2005，9月19-22日，埃及开罗）。提出了一种新的实验通道设施，允许在高雷诺数远远超出以前在实验室中实现的测量，即超过本研究中达到的最高Rem的五倍，同时保持足够高的空间分辨率。
There have been rising concerns regarding the accuracy of measurements in turbulent channel flows, in particular, measurements of the skin-friction results. In the present study, two different methods, namely, mean streamwise pressure gradient (PG) and oil film interferometry (OFI), are used to estimate the wall skin-friction relation, cf = f(Rem), for fully developed turbulent plane-channel flow over a wide range of Reynolds numbers. The channel skin-friction data are then fitted to the well-known logarithmic friction law, providing outstanding agreement with values for the constants of the logarithmic law of the mean velocity profile. A revised logarithmic skin-friction relation is developed, providing good agreement with our skin-friction results and data from the literature, when constants of the logarithmic friction relation adopted from the recent work of Zanoun et al (2003 Phys. Fluids 15 3079–89, 2005 4th Int. Conf. on Heat Transfer, Fluid Mechanics and Thermodynamics, HEAT2005, 19–22 September, Cairo, Egypt) are utilized. A new experimental channel facility is proposed, allowing measurements at high Reynolds numbers well beyond those achieved previously in laboratories, i.e. over five times the highest Rem reached in the present study, while maintaining sufficiently high spatial resolution.