滑面乱流境界層の局所壁面摩擦抵抗係数と平均量特性

抄録

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 R_θ ranges from 840 to 6220. The wall shear stress τ_w, 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 C_f, an empirical formula for C_f and R_θ is proposed and proven to have good accuracy. For the present R_θ 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 R_θ >; 5000. The effect of R_θ on all the turbulent intensities is felt within the sublayer. Both the peak and its location for (uv)^^-/u²_τ increase with R_θ.