Subsonic and Supersonic Flow over Wings Questions and Answers

Assertion (A): The Prandtl-Glauert rule may be used up to a wing's drag-divergence Mach number.

Reason (R): The rule is a linearisation valid only for wholly subsonic flow.

Select the correct answer from the options below.

Assertion (A): A forward-swept wing stalls at the root before the tip.

Reason (R): Forward sweep drives the boundary layer inboard rather than outboard.

Select the correct answer from the options below.

Assertion (A): Winglets are widely fitted to subsonic airliners but rarely to supersonic aircraft.

Reason (R): Induced drag is a much smaller share of the total at supersonic cruise.

Select the correct answer from the options below.

Consider the following statements about sweeping a wing back:

1. It raises the drag-divergence Mach number.

2. It encourages the tip to stall before the root.

3. It increases the maximum lift coefficient of the wing.

Which of the statements given above is or are correct?

Consider the following statements about a supercritical aerofoil:

1. Its upper surface is relatively flat over the forward part of the chord.

2. It carries pronounced aft camber.

3. It prevents any supersonic flow from forming on the surface.

Which of the statements given above is or are correct?

Consider the following statements about the area rule:

1. It concerns the distribution of total cross-sectional area along the aircraft.

2. It led to the waisted fuselages seen on early supersonic aircraft.

3. It applies only above Mach three.

Which of the statements given above is or are correct?

Consider the following statements about a subsonic leading edge:

1. It lies behind the Mach cone from the wing apex.

2. The velocity component normal to it is below sonic speed.

3. It must be made sharp to avoid a detached shock.

Which of the statements given above is or are correct?

Consider the following statements about wave drag on a supersonic wing:

1. It has a component depending on the thickness distribution.

2. It has a component depending on the lift.

3. It disappears entirely if the wing is given a high aspect ratio.

Which of the statements given above is or are correct?

Consider the following statements about slender delta wings:

1. They develop nonlinear vortex lift at high incidence.

2. Their aspect ratio is low compared with a subsonic transport wing.

3. They stall conventionally at about fifteen degrees of incidence.

Which of the statements given above is or are correct?

Consider the following statements about the transonic drag rise on a wing:

1. It begins at the drag-divergence Mach number, above the critical Mach number.

2. It is caused by wave drag and shock-induced separation together.

3. It can be delayed by thinning the section and sweeping the wing.

Which of the statements given above is or are correct?