Boundary Layer Theory MCQ with answer and solution

Concept

Boundary layer formation in real fluids

Formula

NONE

Step-by-step solution

1. Boundary layer theory accounts for the effects of fluid viscosity near a solid boundary. 2. Ideal fluids are assumed to be non-viscous, so no boundary layer forms during ideal fluid flow. 3. Real fluids possess viscosity, which leads to the formation of a boundary layer along solid boundaries. Answer: C

Explanation

Real fluids possess viscosity, which generates internal friction and shear stress against solid boundary surfaces. Ideal fluids are hypothetical and have zero viscosity, meaning no shear stress or boundary layer can form in them. Therefore, boundary layer phenomena occur exclusively in real fluid flows.

Why the other options are wrong

A) Ideal fluids have zero viscosity, so no boundary layer forms. B) Boundary layer formation occurs in external flows as well, not only in pipe flows. D) Boundary layers form over any solid surface immersed in real fluid flow, not just flat plates.

Shortcut

Real fluids have viscosity, which is essential for boundary layer formation.

Common mistake

Thinking boundary layer formation is limited to flat plates or pipes rather than occurring in all real fluids.