CFD Online Discussion Forums - Center of Mass / volume

Hi everyone,

I'm trying to add the calculation of the center of mass in the solver InterFoam. I wrote in interFoam.C :

Code:

vector CoM = sum(mesh.V()*(alpha1*rho1 + (1-alpha1)*rho2)*mesh.C().internalField())/sum(mesh.V()*(alpha1*rho1+(1-alpha1)*rho2));

So far it compiles correctly but the results are wrong. So I added another vector relative to the center of volume :

Code:

vector CoV = sum(mesh.V()*mesh.C().internalField())/sum(mesh.V());

And now it doesn't compile anymore.

I can't see the probleme. If the first line compile, the second should too. Does anyone of you have any idea ?

EDIT :
After some tests it seems the problem is coming from "mesh.C().internalField()". As soon as I use this in the "sum" operator, the dimensions are deleted.
Exemple :
- sum(rho*mesh.V()) -> dimension is kg.
- sum(rho*mesh.V()*mesh.C().internalField() -> dimmensionless.

Is there a way to fix that ?