Lift and Drag coefficient equation in terms of pressure

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Discussion Overview

The discussion centers on the derivation of lift and drag coefficients in terms of pressure, specifically how to calculate these coefficients using pressure values from upper and lower surfaces in a LabVIEW application. The scope includes theoretical equations and practical application for a master's project.

Discussion Character

  • Technical explanation
  • Homework-related
  • Debate/contested

Main Points Raised

  • One participant presents equations for lift and drag coefficients based on pressure differences, expressing uncertainty about their correctness.
  • Another participant suggests that lift can be calculated as a closed loop integral of pressure along the wing surface.
  • Some participants express surprise at the basic nature of the question, implying it should be within the knowledge of a master's level student.
  • A link to a resource on aerodynamics is provided, suggesting that further reading is necessary for a deeper understanding.

Areas of Agreement / Disagreement

There is no consensus on the correctness of the proposed equations, and multiple viewpoints regarding the appropriateness of the question for a master's level discussion are present.

Contextual Notes

Participants have not clarified specific assumptions or definitions related to the equations presented, and there are indications of varying levels of familiarity with the subject matter.

spacegirl101
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I have been trying to find lift and drag coefficients in terms of pressure. So far I have found multiple equations. Below is what I have found after multiple research on the web. I am using these equations in LabVIEW. My input is going to be upper and lower surface pressure and I have to find cl and cd from pressure values in LabVIEW. Here are the equations for cd and cl.

lift coefficient= integral [cp,l(x) - cp,u(x)]d(x/c)
drag coefficient = 0.5*integral[cp*cos(x)]dx

I am not sure if these equations are right or wrong. If they are wrong, can you please provide correct equations? I need these for my MS project. I have been out of school for almost 5 years now and I do not remember all the basics from my BS degree as I have not used my BS knowledge at all in last 5 years.

Thank you.
 
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Hint: lift is the closed loop integral of the pressure along the surface of the wing.

I'm quite shocked you're asking such a basic question at the masters level. This is quite literally an undergraduate lab course question.
 
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Crack open a book on aerodynamics. Wikipedia and the internet are no substitute for real learning.
 
http://highered.mcgraw-hill.com/sites/dl/free/0072472367/211346/Chapter_11.ppt" ==> right click ==> save as

Marq
 
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