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GATE 2023 MT – Question 15

Transport Phenomena and Rate Processes · Fluid flow and momentum transfer · 1 mark · Multiple choice

For laminar fluid flow through a smooth circular tube, the relation between friction factor $f$ and Reynolds number Re is

  1. $f=16/\mathrm{Re}$
  2. $f=24/\mathrm{Re}$
  3. $f=16/\sqrt{\mathrm{Re}}$
  4. $f=24/\sqrt{\mathrm{Re}}$

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Show answer and explanation

Correct answer: (A) $f=16/\mathrm{Re}$

Explanation

Fully developed laminar circular-tube flow gives Fanning friction factor $f=16/\mathrm{Re}$, **A**. The Darcy friction factor would be four times larger, $64/\mathrm{Re}$; the choices use the Fanning convention.