N. Afzal, Power law and log law velocity profiles in fully developed turbulent pipe flow: equivalent relations at large Reynolds numbers, ACT MECHAN, 151(3-4), 2001, pp. 171-183
The classical two layers (the inner and outer layers) from open equations o
f mean turbulent motion, in a fully developed pipe flow, at large Reynolds
number in MMX are matched by the application of the Millikan-Kolmogorov hyp
othesis. In the overlap region, the classical solution of the open function
al equation for the velocity profile is the log law region. It is shown her
e that the open functional equation also possesses another functional solut
ion, the power law velocity profile in the overlap region. The non-unique n
ature of the solution of the open functional equation predicts both a power
law and log law velocity profile. At large Reynolds number the equivalence
of the power law and log law is analysed. The comparison of the theory wit
h classical data of Nikuradse and super-pipe data of Zagarola is encouragin
g.