Question

The flow in which the fluid particles move along well defined paths or stream line and all the stream lines are straight and parallel is known as

• A. Uniform flow
• B. Non-uniform flow
• C. Turbulent flow
• D. Laminar flow

Hint:

Laminar flow $\implies$ Smooth parallel layers, viscous forces dominate.
Turbulent flow $\implies$ Random fluctuating eddies, inertia forces dominate.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Fluid flow regimes are classified as laminar or turbulent based on the Reynolds number and internal flow structure.
Key Formula or Approach:
\[ Re = \frac{\rho v D}{\mu} \quad (Re < 2000 \text{ for laminar flow in pipes}) \]

Step 2: Detailed Explanation:
In laminar flow (also called streamline or viscous flow), fluid particles move smoothly in distinct parallel layers or laminae without microscopic cross-mixing between adjacent layers.
In turbulent flow, fluid particles move in random, chaotic, fluctuating eddy paths.
Uniform flow describes flow parameters remaining constant with distance along the flow path.

Step 3: Final Answer:
Thus, flow along straight, parallel, well-defined streamlines is Laminar flow, corresponding to option (D).