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# Aerodynamics – The Lifting Surface Theory

1 - Question

Is prandtl lifting line theory is a mathematical model that predicts lift distribution over a three-dimensional wing?

a) True

b) False

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Answer: aExplanation: The prandtl lifting line theory is a mathematical models that predicts lift distribution over a three dimensional wing based on its geometry. It is also known as the lanchester-prandtl wing theory. It was used to calculate lift on the wing.

2 - Question

Is vortex loses strength along the whole wingspan?

a) False

b) True

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Answer: bExplanation: The vortex losses the strength along the whole wing span because it is shed as a vortex-sheet from the trailing edge, rather than just at the wing tips.so, the vortex losses its strength on the trailing edge of the wing.

3 - Question

Is lift over each wing segment is correspond?

a) False

b) True

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Answer: aExplanation: On a three dimensional, finite wing, lift over each wing segment does not correspond simply to what two-dimensional analysis predicts. Instead, this local amount of lift is strongly affected by the lift generated at neighboring wing section.

4 - Question

Is it difficult to predict the analytically overall amount of lift?

a) True

b) False

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Answer: aExplanation: It is difficult to predict analytically the overall amount of lift that a wing of given geometry will generate. The lifting line theory yields the lift distribution along the span wise direction based only on the wing geometry and flow conditions.

5 - Question

Is subsonic lifting surface theory relates to normal velocity?

a) True

b) False

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Answer: aExplanation: The basic integral equation of subsonic lifting surface theory relates the normal velocity distribution to the pressure difference distribution on a thin wing and may be written in the form of the lifting surface theory.

6 - Question

Is lifting surface problems evaluated on the basis of loading?

a) True

b) False

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Answer: aExplanation: The classical lifting surface problem is the evaluation of the loading from the equation for a prescribed downwash distribution. Analysis solution exists only for circular or elliptic platforms numerical solutions must be sought.

7 - Question

Is loading distribution is represented by the sum of finite number?

a) True

b) False

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Answer: aExplanation: In the collocation solution of the basic integral equation, the loading distribution is represented by the sum of a finite number of known functions with unknown coefficient substituting the loading representation into their result.

8 - Question

Is downwash distribution on the platform is regular?

a) True

b) False

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Answer: aExplanation: The downwash distribution on the platform is regular if does not exhibit discontinuities or infinities in value. Thus, referring to equation either the downwash modes must be regular, or else the sum of the modes must be regular.

9 - Question

Is plan forms with smooth edge shapes?

a) True

b) False

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Answer: aExplanation: Plane forms with smooth edge shapes with finite tip chord, suitable loading modes are readily defined of the leading and trailing edge respectively and the wing semi span then to ensure that the downwash modes are regular.

10 - Question

Is loading of lifting surfaces antedates the achievements of powered flights?

a) True

b) False

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Answer: aExplanation: The lifting surfaces antedates the achievements of powered flight, efforts have been focused largely on single, almost plane configuration in a steady motion. Since tractability has often been the criteria of the interest.