Re-examination of the Reynolds-Number-Effect on the Mean Flow Quantities in a Smooth Wall Turbulent Boundary Layer.

Measurement of the local skin friction coefficient and re-examination of the Reynolds-number-effect on the mean flow quantities were made in a zero-pressure gradient, smooth wall, turbulent boundary layer. In order to do this fairly, the two-dimensionality of the flow field was carefully adjusted. And, the wall shear stress rw was determined by direct measurement using a floating element device. The Reynolds number based on the momentum thickness R θ =U 1 θ/ν ranges from 840 to 6 220. The present experimental results of c f propose a new empirical formula which well represents the present experimental data and confirms that the Karman constant x= 0.41, which implies a slope of the logarithmic linear layer, is independent of R θ down to R θ =860, whereas the additive constant varies with R θ . The magnitude of the wake parameter takes an asymptotic value of 0.62 if the Reynolds number is sufficiently high. The effect of R θ on all the turbulent intensities is evident even within the viscous sublayer. The constant stress layer does exist in the Reynolds shear stress profiles despite that the constant value varies with R θ