Question

The incompressible flow of air over a curved surface having possible flow separation is schematically shown in the figure. Two zones P and Q are indicated in the figure. Which one of the following combinations is TRUE for zones P and Q? \includegraphics[width=0.5\linewidth]{imagew10.png}

• A. P: (a), (d), (e) and Q: (b), (c), (f)
• B. P: (a), (d), (f) and Q: (b), (d), (f)
• C. P: (a), (c), (f) and Q: (a), (d), (e)
• D. P: (a), (c), (e) and Q: (a), (d), (f)

Hint:

In flow over a curved surface, favorable pressure gradients lead to acceleration and no flow separation, while adverse pressure gradients cause deceleration and possible flow separation.

Answer 1

The Correct Option is A

In the given scenario, air is flowing over a curved surface, and zones P and Q are defined along the flow direction. We need to analyze the flow characteristics in both these zones based on the conditions provided.

Step 1: Analyze Zone P.
In Zone P, the flow is accelerating due to the curvature of the surface. The flow experiences a favorable pressure gradient (the pressure decreases in the direction of flow). There is no flow separation in this region because the flow is still following the surface smoothly. Hence, the conditions in Zone P are:
- (a) Acceleration of flow
- (d) Favorable pressure gradient
- (e) No flow separation

Step 2: Analyze Zone Q.
In Zone Q, the flow is decelerating due to the increasing pressure as the flow moves downstream. This results in an adverse pressure gradient (pressure increases in the direction of flow). As the flow decelerates, the possibility of flow separation increases. Hence, the conditions in Zone Q are:
- (b) Deceleration of flow
- (c) Adverse pressure gradient
- (f) Possible flow separation

Step 3: Conclusion.
Thus, the correct combination of conditions for Zone P and Q is:
- Zone P: (a), (d), (e)
- Zone Q: (b), (c), (f)

Final Answer: \text{(A) P: (a), (d), (e) and Q: (b), (c), (f)}