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for the outer law when the pressure is increasing strongly downstream (as in a diffuser). The inner-wall law typically extends over less than 2 percent of the profile and
can be neglected. Thus we can use Eq. (6.21) as an excellent approximation to solve | v v 336 | e-Text Main Menu | Textbook Table of Contents | Study Guide 6.3 Semiempirical Turbulent Shear Correlations 337 30
Outer law profiles:
Strong increasing pressure
Flat plate flow
Strong decreasing pressure 25 Linear
Eq. (6.22) u+ = y + u+ = er ay u
u* 20 l
lap er Ov 15
10 Experimental data In ne rl ay er 5 Fig. 6.9 Experimental verification
of the inner-, outer-, and overlaplayer laws relating velocity profiles
in turbulent wall flow. 0 10 2
y = y u*
ν 10 1 10 3 10 4 + nearly every turbulent-flow problem presented in this and the next chapter. Many additional applications are given in Refs. 2 and 3.
Air at 20°C flows through a 14-cm-diameter tube under fully developed conditions. The centerline velocity is u0 5 m/s. Esti...
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- Spring '08