ON THE MEASUREMENT OF SKIN FRICTION FROM THE TURBULENT VELOCITY PROFILE

This paper studies the measurement technique for deriving the surface shear, under turbulent pipe and boundary-layer flows, from the velocit y profile. Analytical development of an expression for the full veloci ty profile is described and a recent generalised means of regression c urve fitting enables this profile to be fitted to experimental measure ment. Recent measurements of good quality, using Pitot tubes, hot-wire and laser-doppler anemometers, are used to assess critically, and the n to improve the experimental accuracy of, the empirical coefficient a nd the determination of the surface shear. (C) 1997 Elsevier Science L td.