  It is argued that there are three distinct zones in a wall bounded turbulent
flow field dominated by three completely different mechanisms: - An outer
region where the velocity profile is determined by the pressure distribution -
A highly active wall layer dominated by a sequence of inrush-sweep and
ejections, and - An intermediate region well described by the traditional
logarithmic law proposed by independently Millikan and Prandtl. The log-law and
the wall layer are sometimes referred to as the inner region. Under these
conditions, a unique set of normalisation parameters cannot possibly apply to
all three zones. The inner region can be more successfully represented by
normalising the distance and velocity with the values of these scales at the
edge of the wall layer since they are shared by both the wall layer and the
log-law region. The application of this similarity analysis has successfully
collapsed extensive published data for the inner region covering a range of
Reynolds numbers from 3000 to 1,000,000 in a variety of geometries including
cylindrical pipes, external boundary layers on flat plates, recirculation
regions behind a sudden channel expansion, converging rectangular channels and
oscillating pipe flows into a unique curve. The normalisation also collapsed
drag reducing flow involving ribblets, power law fluids and viscoelastic fluids
onto the standard Newtonian curve.
