Question

In laminar pipe flow, head loss varies with:

• A. Velocity
• B. Velocity squared
• C. Pressure
• D. Temperature

Hint:

Remember: In both laminar and turbulent flows, head loss increases with the square of the velocity in Darcy-Weisbach relation.

Answer 1

The Correct Option is B

In laminar flow, the head loss due to friction in a pipe is given by the Darcy-Weisbach equation and is directly proportional to the square of the velocity.
The relationship for head loss \( h_f \) is: \[ h_f = f \cdot \frac{L}{D} \cdot \frac{v^2}{2g} \] Where:
- \( h_f \) = head loss,
- \( f \) = friction factor,
- \( L \) = length of the pipe,
- \( D \) = diameter of the pipe,
- \( v \) = velocity of flow,
- \( g \) = acceleration due to gravity.
This equation clearly shows that head loss is proportional to \( v^2 \).