# why my drag coefficient still over large

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 July 4, 2009, 09:00 why my drag coefficient still over large #1 New Member   labib Join Date: Jun 2009 Posts: 25 Rep Power: 10 hii...for all i am simulate airfoil with 2D model. i still confuse that in refernce values there are any parameter is area (m2), length(m) and depth(m)..what should i fill the box...that i change the area with value more than 1..the drag coefficient is better ( mean smaller) than using 1...why? can explain me...

July 4, 2009, 14:09
#2
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Ahmed
Join Date: Mar 2009
Location: NY
Posts: 251
Rep Power: 11
Quote:
 Originally Posted by nuimlabib hii...for all i am simulate airfoil with 2D model. i still confuse that in refernce values there are any parameter is area (m2), length(m) and depth(m)..what should i fill the box...that i change the area with value more than 1..the drag coefficient is better ( mean smaller) than using 1...why? can explain me...
1- write down the definition of the drag coefficient
http://en.wikipedia.org/wiki/Drag_coefficient
2- write down the equation for calculating the drag force, the basic equation, not the one given on the wiki, i.e., the integral over the area of the shear stress at the wall
3- answer your question by yourself
Good luck

July 5, 2009, 23:27
#3
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labib
Join Date: Jun 2009
Posts: 25
Rep Power: 10
the chord length of my airfoil is 1 m, with 2D model...so what fill box must i fill in parameter area..in reference value tool box..that the default value is 1..but result of the drag coefficient not accurate enough..what this is influence for drag coefficient..pleace give me more information
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