Flow over Sphere MCQs

By: Prof. Dr. Fazal Rehman | Last updated: May 20, 2025

1. What type of flow typically occurs at very low Reynolds numbers around a sphere?
(A) Turbulent flow
(B) Transitional flow
(C) Laminar creeping flow
(D) Supersonic flow

2. The drag force on a sphere at very low Reynolds number is given by:
(A) Bernoulli’s equation
(B) Blasius formula
(C) Newton’s law of cooling
(D) Stokes’ law

3. Flow separation around a sphere typically occurs at a Reynolds number of approximately:
(A) 1
(B) 10
(C) 1000
(D) 25

4. At high Reynolds numbers, the wake behind a sphere is characterized by:
(A) Laminar flow
(B) Steady flow
(C) Vortex shedding
(D) No separation

5. The pressure drag on a sphere is primarily caused by:
(A) Skin friction
(B) Pressure difference due to flow separation
(C) Buoyancy
(D) Surface roughness only

6. What happens to the drag coefficient of a sphere as Reynolds number increases into the turbulent regime?
(A) It increases continuously
(B) It drops sharply due to delayed separation
(C) It remains constant
(D) It becomes zero

7. Which dimensionless number governs the nature of flow over a sphere?
(A) Mach number
(B) Nusselt number
(C) Reynolds number
(D) Weber number

8. The flow over a sphere is considered steady and symmetric at:
(A) High Reynolds number
(B) Transitional Reynolds number
(C) Low Reynolds number
(D) Sonic speed