Question

Match List-I (Typical occurrence) with List-II (Relevant flow condition) and select the correct answer using the codes given below the lists:

List I (Typical occurrence)	List II (Relevant flow condition)
(a) Cavitation	(1) Absence of fluid velocity
(b) Separation	(2) Fluid pressure reduces to vapor pressure
(c) Stagnation point	(3) Bluff body inflow
(d) Wake	(4) Adverse pressure gradient in widening Boundaries of flow

1. (a) - (4), (b) - (2), (c) - (3), (d) - (1)
2. (a) - (2), (b) - (4), (c) - (3), (d) - (1)
3. (a) - (4), (b) - (2), (c) - (1), (d) - (3)
4. (a) - (2), (b) - (4), (c) - (1), (d) - (3)
5.

Answer 1

Correct Answer - Option 4 : (a) - (2), (b) - (4), (c) - (1), (d) - (3)

Concept:

Cavitation:

• Cavitation is the phenomenon of the formation of vapour bubbles of a flowing liquid in a region where the pressure of the liquid falls below the vapour pressure of the fluid and the sudden collapse of these bubbles in a region of higher pressure.
• Cavitation starts only when the pressure of the liquid falls below the vapour pressure of that liquid.

Flow separation:

• It occurs when the pressure gradient is positive and the velocity gradient is negative
• This positive pressure gradient condition is known as an adverse pressure gradient.

Stagnation point:

• It is the point when a moving fluid is brought to rest i.e. absence of flow velocity.

Wake:

• It is the region downstream of the bluff body where the flow is disturbed and maybe turbulent or separated from the boundary.
• In the wake region, the flow is usually highly unsteady and large eddies or vortices are formed downstream.