CFD Online Discussion Forums - Problems with FAM (fac::grad)

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Problems with FAM (fac::grad)

Hello Dear Forum Users,
as I'm new to the forum firstly I would like to say hi and thank you for all the helpful answers you've done already. I started of with OpenFoam few weeks ago and found help here multiple times yet.
Right now I'm stuck for quite a while and can't help me for myself (still I hope it's quite an easy and trivial problem and it's just due to my inability)...

I'm using foam extend 3.2 and try to write a solver for the shallow water equations based on the finite-area-method. Implementing the equations was straight-forward but while performing some calculations I get an error when compiling:

Code:

// S and H: areaScalarFields, g: dimensionedScalar

areaScalarField  absWL = g*(S+H);

edgeScalarField absWLEdge = fac::interpolate(absWL);

areaVectorField absWLGrad = fac::grad(absWLEdge);

throws:

Code:

/foam-extend-3.2/foam-extend-3.2/src/finiteArea/lnInclude/facGrad.C:58:47: 

error: ‘const Mesh’ has no member named ‘Sf’

     return fac::edgeIntegrate(ssf.mesh().Sf() * ssf);

What I've found out:
- fac::grad(ssf) just calls fac::edgeIntegrate(ssf.mesh().Sf() * ssf)
(where ssf is an edgeMesh)
- ssf.mesh() returns acess to the polyMesh of the faMesh
- the polyMesh should have the member Sf() (returning the surface normal vectors)

Playing around, I tried for example

Code:

areaVectorField absWLGrad = fac::edgeIntegrate(absWLEdge.mesh().Le() * absWLEdge);

where .Le() is the corresponding member function of the faMesh returning the edge normal vectors.
This compiled but I got unphysical results...
And, first of all, I do think that the errors much more likely to be caused by me than by a bug ;)

I'm a little desperate right now and can't find that much documentation about the FAM... any help or comment would be appreciated!

Thank you very much!

Martin

Just in case anybody else stumbles across this:
In the end it worked fine for me when I just left out the middle-line:

Code:

areaScalarField absWL = g*(S+H);

areaVectorField absWLGrad = fac::grad(absWL);

seems like the fac::grad doesn't need an edgeMesh as input...

Quote:

Originally Posted by martinK. (Post 678462)

Just in case anybody else stumbles across this:
In the end it worked fine for me when I just left out the middle-line:

Code:

areaScalarField absWL = g*(S+H);

areaVectorField absWLGrad = fac::grad(absWL);

seems like the fac::grad doesn't need an edgeMesh as input...

Hi martink,

I found there is a problem related to fac::grad() in patch junction. Which I explained here: https://www.cfd-online.com/Forums/op...-2-famesh.html.

If you have understand how to use it or also in doubt, welcome you to discuss it. Thank you.