[wes1204]

hello everyone.

I obtained Cd, Cl, Cm using execFlowFunctionObjects.

------------------------------------------------------------------------------------------
forcesCoeffs
{
type forceCoeffs;
functionObjectLibs ( "libforces.so" ); // lib to load
outputControl timeStep;
outputInterval 1;
patches
(
wall // change to your patch name
);
// name of fields
pName p;
UName U;
log true; // dump to file
rhoName rhoInf;
rhoInf 1.25;
CofR ( 2.3 0.7569 0 );
liftDir ( 0 1 0 );
dragDir ( 1 0 0 );
pitchAxis ( 0 0 1 );
magUInf 1.43;
lRef 0.3537;
Aref 0.3537;

-----------------------------------------------------------------
my case is something like airfoil.

I set pitchAxis( 0 0 1 ).
in this case, which direction is positive in Cm??
clockwise? or countclockwise?

please help me

[wes1204]

anybody help me...

[Tjcross31]

Hi wes,
I know this is years later but this same issue of sign conventions came up in my Masters' project recently - I'm posting here in case anyone should also come across it.

Originally Posted by gfoam

The moment coefficient in libforces.so, is possitive under the rule of the right hand, while in aeronautics, the pitching moment is possitive nose up. I think this may the cause of your differences.
Gonzalo