平行平板クエット乱流の変動速度解析(<小特集>抵抗減少効果とその応用)

概要

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It has been shown that there exists large longitudinal vortical structure in the core region of turbulent plane Couette flow and they are meandering quasi-periodically. In this paper, we study the fluctuating velocity properties in the core region using power-spectrum and wavelet analysis. Power spectrum in the core region of Couette flow demonstrates the existence of a periodic component in the velocity fluctuation. This periodic component has low-frequency amplitude modulation over the turbulent motion. It is shown that the modulation is caused by the meandering motion of the large longitudinal vortical structure. This meandering motion raises another fluctuating velocity in the core region. The velocity fluctuation component due to the meandering motion does not contribute to Reynolds shear stress. In the Couette flow, sweap motion is more dominant than in Poiseuille flow even near the wall. For the Couette flow, the power spectrum in the core region has ω^<-1> distribution.
社団法人日本機械学会の論文
2001-06-25