[id.gomez65]

Hello,

i am doing a simulation of ahmed body with OpenFoam and i know that OpenFoam calculate the drag with this algorithm in the ControlDict.

PHP Code:

forces
{
// rhoInf - reference density
// CofR - Centre of rotation
// dragDir - Direction of drag coefficient
// liftDir - Direction of lift coefficient
// pitchAxis - Pitching moment axis
// magUinf - free stream velocity magnitude
// lRef - reference length
// Aref - reference area
type forceCoeffs;
functionObjectLibs ( "libforces.so" );
outputControl timeStep;
outputInterval 20;
patches
(
ahmed0
);
pName p;
UName U;
log true;
rhoName rhoInf;
rhoInf 1.225;
CofR ( 0 0 0 );
liftDir ( 0 1 0 );
dragDir ( -1 0 0 );
pitchAxis ( 0 0 1 );
magUInf 61.538;
lRef 1;
Aref 0.056016;
} 


i have a doubt about the calculation of Drag, if i use a half of the body with a symmetry plane the Aref has to be the half of the Aref with the entire body?

where i can see the algorithm of calculation of Forces in openFoam?

[tomf]

Hi,

1. Yes for half a body you need half Aref

2. running

find $FOAM_SRC -iname *forceCoeffs.?

In the terminal will give you the locatation of some files with source code.

Regards,
Tom