Question

In laminar flow through pipes, the Reynolds number is typically less than what value?

• A. 500
• B. 1000
• C. 2000
• D. 4000

Hint:

Remember: Laminar flow → $Re<2000$.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The Reynolds number (\(Re\)) is a dimensionless value used to predict the transition from laminar to turbulent flow.
It is calculated as \(Re = \frac{\rho v D}{\mu}\).
Step 2: Detailed Explanation:
For internal flow in pipes, the flow regimes are defined as:
1. Laminar Flow: \(Re<2000\). Flow is smooth and layers do not mix.
2. Transition Flow: \(2000 \leq Re \leq 4000\). Flow is unstable.
3. Turbulent Flow: \(Re>4000\). Flow is chaotic with significant mixing.
Step 3: Final Answer:
Laminar flow occurs when the Reynolds number is less than 2000.