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Usman January 19, 2008 21:33

Airfoil Coordinates
 
Hi Guys

How can i find the coordinates of an airfoil at different angle of attacks. I want to simulate a flow over a NACA 0018 airfoil but i have coordinates for it only at 0 degree angle of attack. I need to get its coordinates @ 3, 9 and 12 degrees angles of attack? Thanks in advance

Regards Usman

ag January 19, 2008 22:03

Re: Airfoil Coordinates
 
Rotate the airfoil. The transformation can be found in any number of references. Or rotate the freestream flow vector.

Usman January 19, 2008 22:19

Re: Airfoil Coordinates
 
Can you explain in a bit more detail how can i rotate the airfoil. What do you mean by number of refernce? I will not be able to use freestream flow vector in my case! Thanks

Usman

A.K. January 20, 2008 06:27

Re: Airfoil Coordinates
 
In order to rotate each given point of your airfoil, use simple formulae available, e.g., at http://en.wikipedia.org/wiki/Rotation_(mathematics)

Usman January 20, 2008 06:37

Re: Airfoil Coordinates
 
Thanks AK i will look into it!

Usman

Usman January 23, 2008 16:41

Re: Airfoil Coordinates
 
Which formulas exactly are we suposse to use to find the co-ordinates for airfoil at an angle of incidence. I am very confused here.

Usman

A.K. January 24, 2008 07:43

Re: Airfoil Coordinates
 
Let (x,y) be the frame of reference in which the inflow velocity is (U,0), and (x',y') be coordinates of an airfoil point.

Now if you rotate the point (x',y') with respect to (x,y) clockwise at an angle "alpha" then

x= x'cos(alpha)+y'sin(alpha);

y= -x'sin(alpha)+y'cos(alpha)


Usman January 24, 2008 07:53

Re: Airfoil Coordinates
 
Thank you very much AK.

Regards Usman


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