摩擦層に於けるレイノルズ應力・混合距離及び亂れ生成のエネルギーの分布(應用力學)

概要

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Reynolds' stress, mixture length and the energy transformed from mean flow to fluctuating flow in the boundary layer were calculated from the measured values of mean velocity using the fundamental equation of fluctuating boundary layer flow. Following important results were obtained : Even in the apparent state of laminar flow before the transition, u'v'≠0 and the additional flow is neither Tollmien's wave nor G.I. Taylor's oscillation. The theory of laminar separation and the theory of instantaneous separation fail to tell the truth about the transition, because distributions near the surface contribute very little to the transformation of energy. The true state of transition is a kind of unstable oscillation with increasing amplitude and with the energy transformation from mean flow to fluctuating flow which is performed within relatively wide range with its centre near 1/4δ from the surface until it reaches the maximum at the midway. Then the flow changes to the type of fully developed turbulent flow with the most of the turbulent energy transformation taking place very near the surface.
宇宙航空研究開発機構の論文
1950-01-20