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-   -   Calculating forces from wings.. (https://www.cfd-online.com/Forums/main/72005-calculating-forces-wings.html)

cjarrett January 22, 2010 01:31

Calculating forces from wings..
 
Please excuse my ignorance but I have a basic question to ask. I've began using CFDesign to start testing some racecar aero properties and want to make sure I'm doing things correctly.

I've got my wing model creating forces in CFDesign, which at 10 deg AoA is around 390 newtons. For planar area, I take the entire area of the wing chord surface and divide by 2, which is 0.528m squared. When I calculate my coefficient of lift I get 0.382 which is 390.027/1215 (dynamic pressure at 45m/s) x 0.528 which is my planform area.. is my calculation correct?

Also, is my measurement of the planform area correct, or should I take the exact dimensions of the wing from the top view when its at 10 degrees? Because the wing is angled away, it will be slightly smaller in area from that view..

Thanks for your patience..

Lysistrata January 22, 2010 22:22

Quote:

Originally Posted by cjarrett (Post 243392)
Please excuse my ignorance but I have a basic question to ask. I've began using CFDesign to start testing some racecar aero properties and want to make sure I'm doing things correctly.

I've got my wing model creating forces in CFDesign, which at 10 deg AoA is around 390 newtons. For planar area, I take the entire area of the wing chord surface and divide by 2, which is 0.528m squared. When I calculate my coefficient of lift I get 0.382 which is 390.027/1215 (dynamic pressure at 45m/s) x 0.528 which is my planform area.. is my calculation correct?

Since you don't know what you are doing, even at the most basic level, I would guess "No". You are just another schmuck who thinks that plugging a geometry into a CFD solver will magically produce results that have merit.
Sorry to disappoint. :p

cjarrett January 23, 2010 14:40

Thanks for your guess.. I assume you came out of the womb with a full understanding of CFD? I see you have nothing better to do on a Friday night so I will just ignore the post. Hopefully someone here is willing to help a beginner. As everyone has to start somewhere :)

Lysistrata January 23, 2010 15:58

Quote:

Originally Posted by cjarrett (Post 243551)
Thanks for your guess.. I assume you came out of the womb with a full understanding of CFD?

No, I didn't. But I did take the time to begin with non-CFD methods so I had an understanding of first principles.


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