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-   -   Questions about Cl,Cd of naca0012 (http://www.cfd-online.com/Forums/openfoam/64696-questions-about-cl-cd-naca0012.html)

darenyang May 20, 2009 07:26

Questions about Cl,Cd of naca0012
 
hello all,
i am new on OF1.5,i want to simulate the naca 0012 wing , i have found experimental results in internet http://www.cyberiad.net/foildata.htm , also i found the parameter of the model, the chord length is 15.24cm, span length 0.91m . i have set my controlDict with forces and forceCoeffs. but i get wrong results , i dont know why ,could anyone help me check my functions _??
functions
(
forces
{
type forces;

// Where to load it from (if not already in solver)
functionObjectLibs ("libforces.so");

patches ( wall );
rhoInf 1.0;
CofR (0 0 0);

}

forceCoeffs
{
type forceCoeffs;

// Where to load it from (if not already in solver)
functionObjectLibs ("libforces.so");

patches ( wall );
rhoInf 1.0;
CofR (0 0 0);
liftDir (0 1 0);
dragDir (1 0 0);
pitchAxis (0 0 0);
magUInf 10;
lRef 0.1524;
Aref 0.1387;

}

dani May 20, 2009 09:53

Hi!

You can try to set pitchAxis to

pitchAxis (0 0 1);

Other parts seem to be correct.
(To tell you all the truth, I'm not sure of the value of Aref, but I think it's ok.)

dani

cwang5 May 26, 2009 07:34

Maybe it's caused by the difference in rho?

I use 1.225 for my calculations...

wikstrom May 26, 2009 14:48

Mabe it's caused by a bad solution?

darenyang June 1, 2009 04:47

thx for all reply,

i used SimpleFoam to simulate ,maybe the slover is not very sufficient
Now i know there is a separation of flow on the chord ,maybe that is why my Cl are lower than the experiment data.
but i need some experiment data for airfoil without separation or reattachment ,just laminar flow over airfoil .

does anyone know where i can find such data ? or could anyone tell me under which conditions is fulfilled for the laminar flow over airfoil?
:):):):)


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