Drag Reduction and Its Application. Analisys of Velocity Fluctuation in Turbulent Plane Couette Flow

Autor:	Futoshi Nishimura, Osami Kitoh, Koichi Nakabayashi
Rok vydání:	2001
Předmět:	Physics::Fluid Dynamics Core (optical fiber) Physics Plane (geometry) Drag Turbulence Mechanical Engineering Taylor–Couette flow Mechanics Condensed Matter Physics Hagen–Poiseuille equation Shear flow Couette flow
Zdroj:	TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B. 67:1345-1352
ISSN:	1884-8346 0387-5016
Popis:	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.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::a50225f0b69f7493d7a527d743dc239d https://doi.org/10.1299/kikaib.67.1345 Zobrazit plný text záznamu