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A comparison of opposition control in turbulent boundary layer and turbulent channel flow

Stroh, A.; Frohnapfel, B.; Schlatter, P.; Hasegawa, Y.

A comparison between classical opposition control applied in the configuration of a fully developed turbulent channel flow and applied locally in a spatially developing turbulent boundary layer is presented. It is found that the control scheme yields similar drag reduction rates if compared at the same friction Reynolds numbers. However, a detailed analysis of the dynamical contributions to the skin friction coefficient reveals significant differences in the mechanism behind the drag reduction. While drag reduction in turbulent channel flow is entirely based on the attenuation of the Reynolds shear stress, the modification of the spatial flow development is essential for the turbulent boundary layer in terms of achievable drag reduction. It is shown that drag reduction due to this spatial development contribution becomes more pronounced with increasing Reynolds number (up to Re τ = 660, based on friction velocity and boundary layer thickness) and even exceeds drag reduction due to attenuation of the Reynolds shear stress. In terms of an overall energy balance, it is found that opposition control is less efficient in the turbulent boundary layer due to the inherently larger fluctuation intensities in the near wall region.

DOI: 10.1063/1.4923234
Zitationen: 19
Web of Science
Zitationen: 16
Zugehörige Institution(en) am KIT Institut für Strömungsmechanik (ISTM)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2015
Sprache Englisch
Identifikator ISSN: 1070-6631
KITopen-ID: 1000054200
Erschienen in Physics of Fluids
Verlag American Institute of Physics (AIP)
Band 27
Heft 7
Seiten Art.Nr. 075101
Nachgewiesen in Web of Science
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