Which of the following is incorrect for a thin, cambered airfoil?

The angle of attack is small

Vortex sheet is kept at the chord line

The slope of the camber line is zero

The induced velocity distribution for the camber line is the same for the chord line

Correct Answer : The slope of the camber line is zero

Explanation : Slope of the camber line \(\frac {dz}{dx}\) is not zero for a cambered airfoil but is some finite value. All the other statements are valid assumptions of thin airfoil theory.

Recently Updated in Aerodynamics Questions

Is laminar flow is used to increase the drag and reduce the lift?

True

False

Can Not Say

None of the above

Correct Answer : Option (A) : True

Explanation : The effect can also be exploited by devices such as aerodynamic spoilers on aircraft, which deliberately spoil the laminar flow to increase the drag and reduce the lift on the aircraft, which also used as a break to stop the aircraft

Example of turbulent flow?

Laminar flow

Flow on a symmetric airfoil

Smoking rises from cigarette

Turbulent flow on the airfoil

Correct Answer : Option (C) : Smoking rises from cigarette

Explanation : Smoke rising from a cigarette is mostly turbulent flow. However, for the first few centimeters, the flow is laminar. The smoke plume becomes turbulent as its Reynolds number increases, due to its flow velocity and the characteristic length.

Is lift is generated due to large pressure gradients on the upper side of the airfoil?

True

False

Can Not Say

None of the above

Correct Answer : Option (A) : True

Explanation : At higher angles, very large adverse pressure gradients that develop on the upper side as the airfoil attempts to generate more lift causes the boundary layer to separate, leading to a major disruption of the flow over the airfoil and the wing stalls.