Flow of air develops in a horizontal cylindrical duct, of diameter D 5 15 in., following a well-rounded entrance. A turbulent boundary grows on the duct wall, but the flow is not yet fully developed....

Flow of air develops in a horizontal cylindrical duct, of

diameter D 5 15 in., following a well-rounded entrance. A

turbulent boundary grows on the duct wall, but the flow is not

yet fully developed. Assume that the velocity profile in the

boundary layer is u=U 5 ðy=δÞ

1=7

. The inlet flow is U 5 50 ft/s

at section 1 . At section 2 , the boundary-layer thickness is

δ2 5 4 in. Evaluate the static gage pressure at section 2 ,

located at L 5 20 ft. Find the average wall shear stress.