This paper is concerned with the measurement of the velocity distribution and
determination of the local skin friction coefficient for turbulent boundary layer developing on
smooth and finned surfaces. The finned surface has a uniform roughness, which takes the shape of
sinewave fins arranged in the transvers direction of ttie flow. The results indicated that the value
of sldn friction coefficient is greatly increased for the finned surface case. The Reynolds number
has no effect on the turbulent velocity profiles through the overlap region, when it was
represented using the inner-law variables u"*􀀀 and y"*" for both the finned and the smooth surfaces