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analysis partially with experimental research。 Nevertheless； these fruitful results
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remain with inconsistencies in both theory and practice。
Firstly； for a definite shear stress
？ o = ？ hJ； the effect of wall roughness is
assumed to be only limited to a shallow region of viscous sublayer adjacent to the
wall； while the velocity distribution in the turbulent core is assumed to be identical
for all conditions of flow。
Secondly； assumption has been made that the turbulent core velocity curve u~y
joins abruptly the viscous film straight line at the point of depth y = δ=11。6？ /u* ；
where u* is the shear velocity and ？ ； the kinematic viscosity。 This is far from truth
as shown by many recent velocity measurements close to the boundary （1） 。 The slopes
du
of velocity gradients
dy
for the two regimes are radically different。
Thirdly； in puting the average velocity by summation； the effect of flow
within the range y