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ELEMENTARY MECHANICS OF FLUIDS
CE 319F - FALL 1997 (KINNAS)
DEPARTMENT OF CIVIL ENGINEERING
ENVIRONMENTAL AND WATER RESOURCES ENGINEERING

TURBULENT FLOW INSIDE PIPES
(Re>3,000)

Definitions:

• shear stress acting on the fluid
• ``apparent'' or Reynolds shear stress
• V=Q/A: mean velocity (the ``bar'' is omitted for simplicity)
• Reynolds number
• head loss
• f: resistance coefficient or friction factor

The Darcy-Weisbach equation:

f FOR SMOOTH PIPES (Prandtl formula):

f FOR ROUGH PIPES: (Colebrook-White formula):

The Moody chart (Fig. 10.8 of the textbook) also provides f.

where is the relative roughness of the pipe.

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