Further Developments in Turbulence Management pp 255-266 | Cite as
Viscous sublayer analysis of riblets and wire arrays
Abstract
Ever since it was observed [1] that the experimentally effective spacing of riblets for turbulent drag reduction is of the same order of magnitude as the thickness of the viscous sublayer of the turbulent stream, it has been clear that the viscous sublayer plays a dominant role in the mechanics of this effect. Within the viscous sublayer we are allowed to neglect nonlinearities and thus to concentrate on the Stokes, low Reynolds number, flow of a viscous fluid along a corrugated surface. Bechert and Bartenwerfer [2] analysed longitudinal mean flow in this approximation and obtained a characterization of the surface in terms of the parameter “protrusion height”, namely the distance from the riblet tips to the virtual plane surface that the velocity profile appears to originate from. Bechert et al. [3] studied transverse flow across the riblets experimentally and by means of an analogical simulation, and measured a protrusion height for this flow as well.
Keywords
Drag Reduction Stoke Flow Streamwise Vortex Wire Array Viscous SublayerPreview
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References
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