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P6.57 John Laufer (NACA Tech. Rep. 1174, 1954) gave velocity
data for 20°C airflow in a smooth 24.7-cm-diameter pipe
at Re 5 E5:
u/uCL 1.0 0.997 0.988 0.959 0.908 0.847 0.818 0.771 0.690
r/R 0.0 0.102 0.206 0.412 0.617 0.784 0.846 0.907 0.963 The centerline velocity uCL was 30.5 m/s. Determine
(a) the average velocity by numerical integration and
(b) the wall shear stress from the log-law approximation.
Compare with the Moody chart and with Eq. (6.59).
P6.58 In Fig. P6.55 assume that the pipe is cast iron with L 550
m, d 7 cm, and Z 100 m. If an 80 percent efficient Textbook Table of Contents | Study Guide 410 Chapter 6 Viscous Flow in Ducts pump is placed at point B, what input power is required to
deliver 160 m3/h of water upward from reservoir 2 to 1?
P6.59 The following data were obtained for flow of 20°C water
at 20 m3/h through a badly corroded 5-cm-diameter pipe
which slopes downward at an angle of 8°: p1 420 kPa,
z1 12 m, p2 250 kPa, z2 3 m. Estimate (a) the
roughness ratio of the pipe and (b) the percent change in
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This note was uploaded on 10/27/2009 for the course MAE 101a taught by Professor Sakar during the Spring '08 term at UCSD.
- Spring '08