Realistic air velocties regarding a wing while in flight

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Discussion Overview

The discussion revolves around determining realistic air velocities over and under an aerofoil during flight, particularly in the context of a plane traveling at a constant altitude and an average speed of 250 m/s. The inquiry seeks generalized values rather than specifics related to particular airfoil shapes.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant requests information on realistic air velocities over and under an aerofoil, emphasizing the need for the velocity over the top to be greater than that underneath.
  • Another participant suggests consulting the book "Theory of Wing Sections" for tabulated data on various airfoil shapes, indicating that such resources contain relevant information.
  • The original poster expresses a lack of access to a library and clarifies that they are looking for generalized values rather than specific airfoil shapes.
  • A later reply notes that the velocity ratio over the top of an airfoil typically ranges between 1.2 to 1.5, while the velocity on the bottom is usually just below 1 for most of the chord length.

Areas of Agreement / Disagreement

Participants do not reach a consensus on specific values, and there is an acknowledgment that the shape of the aerofoil significantly influences the air velocity ratios.

Contextual Notes

The discussion highlights the dependence on the shape of the aerofoil and the lack of access to specific resources for obtaining data, which may limit the accuracy of the proposed values.

Bill_Nye_Fan
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I want to know what values would be realistic for the air velocities both going over the top of an aerofoil and going underneath an aerofoil (that is, the velocity over the top of the wing should be greater than the velocity over the bottom by a reasonable amount). Also, the plane is traveling at a unchanging altitude and is moving at an average velocity of 250 m/s.

Sorry if this doesn't really make sense, I just really need to know. I will clarify any questions you may have about this. Thank you guys for your help.
 
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Do you have access to a library like at a university? If you check out the book Theory of Wing Sections by Abbott and Von Doenhoff it has that sort of data tabulated at the end in appendices for a number of different airfoil shapes.
 
I am sadly unable to get access to a library at the moment.

Also, I'm not really interested in the shape of the aerofoil currently. I'm looking more generalised values, but I would still like them to be realistic.

Anyway, thank you for your time nonetheless!
 
It really depends on the shape though. The value of ##u/U_{\infty}## over the top of an airfoil is going to be less than 2 and greater than 1. Usually it's going to peak in the range of 1.2 to 1.5 or so. On the bottom it is usually somewhere just below 1 for most of the chord length.
 

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