What is the purpose of supercritical airfoil?

Reduce critical Mach number

Reduce drag divergence Mach number

Increase drag divergence Mach number

Increase lift of the airfoil at supersonic speed

Correct Answer : Increase drag divergence Mach number

Explanation : The purpose of a supercritical airfoil to delay the drag divergence Mach number so that there is a delay in wave drag formation which begins at the transonic speed. It aims to increase the Mach number increment between the critical Mach number and drag divergence Mach number.

Recently Updated in Aerodynamics Questions

What happens to the coefficient of pressure in a supersonic flow for an increase in Mach number?

Increases

Decreases

Remains unaffected

First increases then decreases

Correct Answer : Option (B) : Decreases

Explanation : For linearized supersonic flow, the coefficient of pressure is inversely proportional to

Thus, when the Mach number increases, the coefficient of pressure decreases. This in contrast to the trend followed by the subsonic flow where an increasing Mach number results in decreasing coefficient of pressure.

What is the source of wave drag exerted on the supersonic airfoil?

Skin friction

Trailing vortex

Shock waves

Viscous boundary layer

Correct Answer : Option (C) : Shock waves

Explanation : Wave drag is a result of pressure distribution which is exerted over the airfoil. This is a consequence of formation of shock waves and expansion wave pattern due to the presence of supersonic flow.

What is the lift coefficient over a flat plate at an angle of attack of 3 degrees in a supersonic flow at Mach 4?

0.0512

0.0541

0.0628

0.0714

Correct Answer : Option (B) : 0.0541

Explanation :