Project ForgeFluid Mechanics
Flow Through Pipes
GATE 2012
Medium
Water is flowing under laminar conditions in a pipe of length L. If the diameter of the pipe is doubled, for a constant volumetric flow rate, the pressure drop across the pipe
- Adecreases 2 times
- decreases 16 times
- Cincreases 2 times
- Dincreases 16 times
Explanation
Hagen-Poiseuille: ΔP=128μLQ/(πD⁴). For fixed Q, ΔP∝1/D⁴. Doubling D reduces ΔP by a factor of 2⁴=16.
Source: GATE CH 2012 (2012)
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