Darcy’s formula for head loss in pipes is expressed as hf=4fl v2 / __________________?
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Answer: A. 2gd
Explanation
Darcy-Weisbach head loss formula for pipe flow uses the denominator 2gd (or 2gD). This dimensional denominator arises from kinetic energy conversion terms in the mechanical energy balance equations. Frictional head loss varies directly with pipe length and velocity squared, and inversely with pipe diameter. The Darcy-Weisbach equation is the universally accepted formula for calculating head loss in closed pipe systems. Variables in the formula include friction factor, pipe length, internal diameter, flow velocity, and gravity. Darcy formulated initial resistance relationships later refined by Weisbach into this standard engineering equation.
Municipal water distribution engineers use the Darcy-Weisbach equation to size pipes and select booster pumps. Accurate head loss calculations ensure adequate pressure delivery to domestic and industrial water consumers. Computerized pipe network models rely on these fundamental friction equations to simulate hydraulic performance. gd without the factor of two is dimensionally incorrect for kinetic energy head loss calculations in pipe flow. g2d features an incorrect gravitational acceleration squared term that violates standard dimensional homogeneity. gd2 places the diameter squared incorrectly in the denominator instead of matching standard pipe flow formulas.
- Subject
- Agriculture
- Category
- Agriculture
- Topic
- —
- Difficulty
- medium
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