The shear stress in a fully developed laminar flow in a circular pipe
- Ais maximum at the pipe wallCorrect
- Bis minimum at the pipe wall
- Cis maximum at the pipe centre
- Dvaries parabolically across the section
Solution
Concept
Shear stress distribution in pipe flow
Formula
NONE
Step-by-step solution
1. Shear stress in fully developed pipe flow varies linearly from zero at the pipe centerline to a maximum at the pipe boundary wall. Answer: A
Explanation
In fully developed laminar pipe flow, shear stress varies linearly across the radius, being zero at the pipe center where velocity is maximum. The shear stress reaches its maximum value at the pipe wall due to boundary friction and high velocity gradients. Therefore, option A is correct.
Why the other options are wrong
B) Shear stress reaches its peak at the wall rather than its minimum. D) Shear stress distribution across the pipe cross-section is linear rather than parabolic.
Shortcut
Shear stress in pipe flow varies linearly from zero at the center to maximum at the pipe wall.
Common mistake
Confusing the linear shear stress distribution with the parabolic velocity distribution which is maximum at the pipe center.
Correct answer: A) is maximum at the pipe wall