滑面乱流境界層の外層構造に及ぼすレイノルズ数の効果 : 統計的性質の再吟味〔流体工学, 流体機械〕

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Re-examination of the low-Reynolds-number effect on the outer layer structure has been made in a zero pressure gradient, smooth wall turbulent boundary layer where the two-dimensionality of a flow field was corroborated using the momentum integral equation. The measurements associated with the higher-order moments and the conditional averages were made over a momentum thickness Reynolds number range 840&InE;R_θ&InE;6120. The magnitude of the triple products normalized with friction velocity and relative typical eddy scale C_x/δ are affected with a achievement level of the two-dimensionality of a flow field. For R_θ<2130,the absolute values of the triple products and the turbulent diffusion terms normalized with outer variables increase with R_θ. Intermittency factor is approximately independent of R_θ when R_θ is greater than 4410. Therefore, average turbulent and non-turbulent zone lengths are constant independent of R_θ.
1998-04-25