Local Skin Friction Coefficient Evaluated by Direct Measurement Method and Mean Flow Quantities in a Turbulent Boundary Layer.
Local Skin Friction Coefficient Evaluated by Direct Measurement Method and Mean Flow Quantities in a Turbulent Boundary Layer.
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通过直接测量方法和湍流边界层中的平均流量评估局部表面摩擦系数。
DOI：
10.1299/kikaib.62.2230
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
S. Mochizuki
中科院分区：
文献类型：
--
作者：
H. Osaka;T. Kameda;S. Mochizuki
在零压力梯度湍流边界层中测量了局部表面摩擦系数，并重新考察了低雷诺数效应。动量厚度雷诺数Rθ范围为840 ~ 6220。壁面剪应力τw是在流场中用浮动元件装置直接测量的方法确定的，在流场中边界层的二维性得到了彻底的检验。根据已有的计算结果，提出了一个计算Cf和Rθ的经验公式，并证明了该公式具有较好的精度。对于目前的Rθ范围，存在一个常数χ的对数区域。然而，附加常数C随雷诺数而变化。当Rθ > 5000时，尾流参数的大小保持0.62的恒定值。Rθ对湍流强度的影响主要表现在亚层内。（uv）^-/u2τ的峰值及其位置均随Rθ的增大而增大。
Measurement of the local skin friction coefficient and re-examination of the low-Reynolds-number effect are made in a zero pressure gradient turbulent boundary layer. The momentum thickness Reynolds number Rθ ranges from 840 to 6220. The wall shear stress τw, is determined from the direct measurement method using a floating element device in a flow field where the two-dimensionality of a boundary layer is examined thoroughly. From the present results of Cf, an empirical formula for Cf and Rθ is proposed and proven to have good accuracy. For the present Rθ range, a log region with a constant χ exists. The additive constant C, however, varies with the Reynolds number. The magnitude of the wake parameter maintains a constant value of 0.62 for Rθ >; 5000. The effect of Rθ on all the turbulent intensities is felt within the sublayer. Both the peak and its location for (uv)^-/u2τ increase with Rθ.