A method for determination of turbulent skin friction when the coefficients of log-law may differ from universal constants

A simple method is proposed for the determination of skin friction from the measured two-dimensional turbulent boundary layer mean.velocity profile,(a) the log-law to the overlap region or (b) the equation of Coles to a large portion of tihe velocity profile by an iterative proceuure, The distinguishing fedcure of Lhe rnethc-1 is that the coefficients of tile 1ogarithmic part of the mean velocity may not have to be luiown apriori.Consequently, the can take values other than those vcilucs of universal log-law. Comparison with experimental data of flow cownstream of flat plate turbulence manipulators (ribbons) and for interaction of airfoil wake with boundary layer, suggests that the method sives results cmparable13; with taose obtained by balance and fence.13