Question

The flow separation occurs when the fluid travels away from the __________

(a) Surface

(b) Fluid body

(c) Adverse pressure gradient

(d) Inter-molecular spaces

This question was posed to me in semester exam.

This intriguing question originated from Separation of Boundary Layer in division Boundary Layer Flow & Forces on Sub-merged Bodies of Fluid Mechanics

Answer 1

Correct option is (c) Adverse pressure gradient

To explain I would say: Adverse pressure gradient takes place when the static pressure increases. It increases the direction of the flow. Adverse pressure gradient plays an important role in flow separation. Thus, option c is correct.