help needed with fvc::div()

johanna · August 31, 2009, 04:54

I have tried to do an equation that is solved using fvScalarMatrix. One of the terms in this equation is (Ua+Ub)div(kab),
where Ua and Ub are volVectorField and kab is volScalarField and also the unknown of this equation.

I have tried to do this term by using the following
(Ua+Ub) & fvc::div(kab) in the fvScalarMatrix.

I also tried to do this fvc::div(kab) outside the ScalarMatrix to see if it works that way. I get an error message.
"createFields.H:332: error: no matching function for call to 'div(Foam::volScalarField&)' "

Could someone help me and tell me what I'm doing wrong? I don't have a lot of experience with OpenFoam yet.
There are similar equations in my code, that work just fine, but in those the divergence term is normal.

Johanna

niklas · August 31, 2009, 05:36

divergence of a scalar!!!
The error message cant be much clearer.

divergence works on vectors...returns a scalar.
grad works on scalars....returns a vector

johanna · August 31, 2009, 08:12

I have been laughing at myself here when I read your reply.

Thanks!

August 31, 2009, 04:54	help needed with fvc::div()	#1
johanna New Member Johanna Airaksinen Join Date: Mar 2009 Posts: 5 Rep Power: 17	I have tried to do an equation that is solved using fvScalarMatrix. One of the terms in this equation is (Ua+Ub)div(kab), where Ua and Ub are volVectorField and kab is volScalarField and also the unknown of this equation. I have tried to do this term by using the following (Ua+Ub) & fvc::div(kab) in the fvScalarMatrix. I also tried to do this fvc::div(kab) outside the ScalarMatrix to see if it works that way. I get an error message. "createFields.H:332: error: no matching function for call to 'div(Foam::volScalarField&)' " Could someone help me and tell me what I'm doing wrong? I don't have a lot of experience with OpenFoam yet. There are similar equations in my code, that work just fine, but in those the divergence term is normal. Johanna

August 31, 2009, 05:36		#2
niklas Super Moderator Niklas Nordin Join Date: Mar 2009 Location: Stockholm, Sweden Posts: 693 Rep Power: 29	divergence of a scalar!!! The error message cant be much clearer. divergence works on vectors...returns a scalar. grad works on scalars....returns a vector atulkjoy likes this.

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August 31, 2009, 08:12		#3
johanna New Member Johanna Airaksinen Join Date: Mar 2009 Posts: 5 Rep Power: 17	I have been laughing at myself here when I read your reply. Thanks!