Obtaining Forces and Force Coefficients

ShuToshio · July 24, 2012, 00:08

Hi,

I have been trying to run icoFoam for a bluff body flow, and I have just included the forces and forceCoeffs functions, but I wasn't able to get any results when I ran icoFoam. There were no new directories created.

I read in some previous threads that it worked in OF 1.5 or 1.6. I am using 2.1.x, has there been any changes? My controlDict functions goes like this

functions{
forces{

type forces;
functionObjectLibs ("libforces.so");
patches (
carfront
);
rhoInf 1.204;
CofR (0 0 0);
}

forceCoeffs
{
type forceCoeffs;
functionObjectLibs ("libforces.so");
patches (
carfront
);
rhoInf 1.204;
CofR (0 0 0);
liftDir (0 0 1);
dragDir (1 0 0);
pitchAxis (0 0 0);
magUInf 1.0;
lRef 5;
Aref 6;
}
};

Also, is it true that I can only include one patch?

niaz · July 24, 2012, 05:20

I think you should add something like this to your function lines
outputControl timeStep;
outputInterval 10;

ShuToshio · July 24, 2012, 22:35

I tried, doesnt work

niaz · July 25, 2012, 01:05

I used it for my project in OF2.1.1. it works, try it.

libs
(
"libOpenFOAM.so"
"libforces.so"
);

functions
{
forces
{
type forces;
functionObjectLibs ("libforces.so");
outputControl timeStep;
outputInterval 10;
patches (wall);
pName p;
UName U;
rhoName rhoInf;
log true;
rhoInf 1;
CofR (5 6 0.5);
}

forces1
{
type forceCoeffs;
functionObjectLibs ( "libforces.so" );
outputControl timeStep;
outputInterval 10;
patches
(
wall
);
pName p;
UName U;
rhoName rhoInf;
log true;
rhoInf 1;
CofR ( 5 6 0.5 );
liftDir ( 0 1 0 );
dragDir ( 1 0 0 );
pitchAxis ( 0 0 1 );
magUInf 1;
lRef 1;
Aref 1;
}

}

July 24, 2012, 00:08	Obtaining Forces and Force Coefficients	#1
ShuToshio New Member Steven Chew Join Date: Jul 2012 Posts: 4 Rep Power: 14	Hi, I have been trying to run icoFoam for a bluff body flow, and I have just included the forces and forceCoeffs functions, but I wasn't able to get any results when I ran icoFoam. There were no new directories created. I read in some previous threads that it worked in OF 1.5 or 1.6. I am using 2.1.x, has there been any changes? My controlDict functions goes like this functions{ forces{ type forces; functionObjectLibs ("libforces.so"); patches ( carfront ); rhoInf 1.204; CofR (0 0 0); } forceCoeffs { type forceCoeffs; functionObjectLibs ("libforces.so"); patches ( carfront ); rhoInf 1.204; CofR (0 0 0); liftDir (0 0 1); dragDir (1 0 0); pitchAxis (0 0 0); magUInf 1.0; lRef 5; Aref 6; } }; Also, is it true that I can only include one patch?

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July 24, 2012, 05:20		#2
niaz Senior Member A_R Join Date: Jun 2009 Posts: 122 Rep Power: 17	I think you should add something like this to your function lines outputControl timeStep; outputInterval 10;

July 24, 2012, 22:35		#3
ShuToshio New Member Steven Chew Join Date: Jul 2012 Posts: 4 Rep Power: 14	I tried, doesnt work

July 25, 2012, 01:05		#4
niaz Senior Member A_R Join Date: Jun 2009 Posts: 122 Rep Power: 17	I used it for my project in OF2.1.1. it works, try it. libs ( "libOpenFOAM.so" "libforces.so" ); functions { forces { type forces; functionObjectLibs ("libforces.so"); outputControl timeStep; outputInterval 10; patches (wall); pName p; UName U; rhoName rhoInf; log true; rhoInf 1; CofR (5 6 0.5); } forces1 { type forceCoeffs; functionObjectLibs ( "libforces.so" ); outputControl timeStep; outputInterval 10; patches ( wall ); pName p; UName U; rhoName rhoInf; log true; rhoInf 1; CofR ( 5 6 0.5 ); liftDir ( 0 1 0 ); dragDir ( 1 0 0 ); pitchAxis ( 0 0 1 ); magUInf 1; lRef 1; Aref 1; } }