John Laufer (NACA Tech Rep. 1174, 1954) gave velocity data 20°C airflow in a smooth 24.7-cm-diameter
![2046_0f883ab7-b364-4ee5-ba64-08826f564e50.png](https://secure.tutorsglobe.com/CMSImages/2046_0f883ab7-b364-4ee5-ba64-08826f564e50.png)
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. (6.43).