The effect of Reynolds number on boundary layer turbulence

A new facility for studying high Reynolds number incompressible turbulent b oundary layer flows has been constructed. It consists of a moderately sized wind tunnel, completely enclosed by a pressure vessel, which can raise the ambient air pressure in and around the wind tunnel to 8 atmospheres. This results in a Reynolds number range of about 20:1, while maintaining incompr essible flow. Results are presented for the zero pressure gradient flat pla te boundary layer over a momentum thickness Reynolds number range 1500-1500 0. Scaling issues for high Reynolds number non-equilibrium boundary layers are discussed, with data comparing the three-dimensional turbulent boundary layer flow over a swept bump at Reynolds numbers of 3800 and 8600. It is f ound that successful prediction of these types of flows must include length scales which do not scale on Reynolds number, but are inherent to the geom etry of the flow. (C) 1999 Elsevier Science Inc. All rights reserved.