Question

For the flow through a pipe, if Reynolds's number is greater than 4000, it indicates:

• A. Streamline flow
• B. Laminar flow
• C. Steady flow
• D. Turbulent flow

Hint:

Reynolds's number is crucial in determining the flow regime. A high Reynolds number typically indicates turbulent flow, while a low number indicates laminar flow.

Answer 1

The Correct Option is D

Step 1: Reynolds Number Explained.
Reynolds number (\( Re \)), a dimensionless value, predicts fluid flow behavior. It's calculated as: \[ Re = \frac{\rho v D}{\mu} \] Where: \( \rho \) = fluid density \( v \) = fluid velocity \( D \) = characteristic length (e.g., pipe diameter) \( \mu \) = dynamic viscosity
Step 2: Flow Types.
- \( Re<2000 \): Laminar flow (smooth) - \( Re>4000 \): Turbulent flow (chaotic) - \( 2000<Re<4000 \): Transitional flow (between laminar and turbulent)
Step 3: Answer.
A Reynolds number above 4000 signifies turbulent flow. Thus, the correct choice is (D).