Forces calculation

fusij · October 22, 2010, 12:53

Hello OpenFOAM users&fans,

I am new to OpenFOAM and I am simulating a 2D flow over a cylinder with pisoFoam.

When I am trying to find the forces, the forces.dat file only shows brackets full of zeros. The forces code seen below creates a forces/0 folder where forces.dat is located. I am referring to the right patch in the code. Do you have some suggestions or ideas of what could be wrong?

This is my forces code in my controlDict.h

functions
(
forces
{
type forces;
functionObjectLibs ( "libforces.so" ); outputControl timeStep;
outputInterval 1;
patches (wall);
pName p;
UName U;
log true;
rhoName rhoInf;
rhoInf 1025;
CofR ( 0 0 0 );
}
);

NickG · October 29, 2010, 11:23

Hi

Is your cylinder named wall? If not change the

patches (wall);

line in forces{... } to

patches (whatever you've called it);

Hope that helps

Nick

vkrastev · October 29, 2010, 11:30

If the patch name is correct, try also to remove the lines beginning with pName and Uname: judging by other treads in the forum, these lines can give some troubles in the 1.7.x versions of OpenFOAM.

Regards

V.

Aerospace · October 29, 2010, 11:50

Any one knows if there are problems with force function in 3D multifaces patch?

Thankyou.

fusij · October 29, 2010, 12:38

It was just a stupid mistake, for some reason I had changed my patch name to something else than "wall". It is fixed now, thank you.

October 22, 2010, 12:53	Forces calculation	#1
fusij Member Join Date: Nov 2009 Posts: 56 Rep Power: 17	Hello OpenFOAM users&fans, I am new to OpenFOAM and I am simulating a 2D flow over a cylinder with pisoFoam. When I am trying to find the forces, the forces.dat file only shows brackets full of zeros. The forces code seen below creates a forces/0 folder where forces.dat is located. I am referring to the right patch in the code. Do you have some suggestions or ideas of what could be wrong? This is my forces code in my controlDict.h functions ( forces { type forces; functionObjectLibs ( "libforces.so" ); outputControl timeStep; outputInterval 1; patches (wall); pName p; UName U; log true; rhoName rhoInf; rhoInf 1025; CofR ( 0 0 0 ); } );

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October 29, 2010, 11:23		#2
NickG Member Nick Gardiner Join Date: Apr 2009 Location: Chichester, UK Posts: 94 Rep Power: 17	Hi Is your cylinder named wall? If not change the patches (wall); line in forces{... } to patches (whatever you've called it); Hope that helps Nick

October 29, 2010, 11:30		#3
vkrastev Senior Member Vesselin Krastev Join Date: Jan 2010 Location: University of Tor Vergata, Rome Posts: 368 Rep Power: 20	If the patch name is correct, try also to remove the lines beginning with pName and Uname: judging by other treads in the forum, these lines can give some troubles in the 1.7.x versions of OpenFOAM. Regards V.

October 29, 2010, 11:50		#4
Aerospace New Member Juanito Join Date: Oct 2010 Posts: 27 Rep Power: 16	Any one knows if there are problems with force function in 3D multifaces patch? Thankyou.

October 29, 2010, 12:38		#5
fusij Member Join Date: Nov 2009 Posts: 56 Rep Power: 17	It was just a stupid mistake, for some reason I had changed my patch name to something else than "wall". It is fixed now, thank you.