With increasing aging of pipes, the ratio of maximum velocity to mean velocity in turbulent flow
- Ainitially decreases and then increases
- Binitially increases and then decreases
- Cdecreases
- DincreasesCorrect
Solution
Concept
Effect of roughness on velocity profile
Formula
Vmean/Vmax = 1/(1 + 1.43√f)
Step-by-step solution
1. Aging increases roughness, so the friction factor f increases. 2. Vmean/Vmax decreases with f, so Vmax/Vmean increases.
Explanation
A rougher pipe gives a less flat velocity profile.
Shortcut
Rougher → peakier profile.
Correct answer: D) increases