Boundary layer theory MCQs – Aerospace

1. Boundary layer theory is used to describe:
(A) The flow of air around an aircraft
(B) The heat transfer in aircraft engines
(C) The aerodynamic forces on the aircraft
(D) The structural strength of aircraft materials

2. The boundary layer is defined as:
(A) The region where flow is inviscid
(B) The region where flow speed is zero
(C) The layer of fluid in immediate contact with a surface where viscous effects are significant
(D) The layer where flow velocity is maximum

3. In boundary layer theory, the no-slip condition states that:
(A) The fluid velocity is equal to the surface velocity
(B) The fluid velocity is zero at the surface
(C) The fluid velocity is maximum at the surface
(D) The fluid velocity is constant across the boundary layer

4. The thickness of the boundary layer generally:
(A) Decreases with increasing distance from the leading edge
(B) Increases with increasing distance from the leading edge
(C) Remains constant along the surface
(D) Decreases with increasing flow speed

5. The transition from laminar to turbulent boundary layer occurs due to:
(A) Decreasing Reynolds number
(B) Increasing Reynolds number
(C) Decreasing surface roughness
(D) Increasing temperature

6. The boundary layer can be classified as:
(A) Laminar, transitional, and turbulent
(B) Inviscid, laminar, and turbulent
(C) Compressible, incompressible, and transitional
(D) Steady, unsteady, and compressible

7. The boundary layer thickness at a point along a surface is influenced by:
(A) Flow velocity and surface roughness
(B) Surface temperature and fluid density
(C) Surface area and fluid viscosity
(D) Surface shape and fluid pressure

8. In laminar boundary layers, the flow is characterized by:
(A) Smooth and orderly motion
(B) Chaotic and irregular motion
(C) High turbulence intensity
(D) No-slip conditions at the surface

9. Turbulent boundary layers typically have:
(A) Higher heat transfer rates
(B) Lower drag coefficients
(C) Smooth and stable flow
(D) Lower frictional forces

10. The Blasius solution is associated with:
(A) Laminar boundary layers over a flat plate
(B) Turbulent boundary layers over a flat plate
(C) Compressible boundary layers over a curved surface
(D) Boundary layers in rotating fluids