Questions about simplefoam

maoyanren · March 5, 2013, 12:11

Hi all,

I am relatively new to OpenFOAM and I have a question about the solver simpleFoam. I am using OF 2.1.1.

I read a little bit about the solver and algorithm and had some understanding of it. One thing confuses me though. In the source code of simpleFoam

UEqn.H
"tmp<fvVectorMatrix> UEqn
(
fvm::div(phi, U)
+ turbulence->divDevReff(U)
==
sources(U)
);

UEqn().relax();

sources.constrain(UEqn());

solve(UEqn() == -fvc::grad(p));"

why is there a "sources(U)" term in the UEqn and it is even a function of U? And what is "sources.constrain(UEqn())" for?

Any help will be appreciated.

anishtain4 · March 6, 2013, 02:16

Digging it in doxygen you first get to IObasicSourceList which is a derivative of IOdictionary and basicSourceList. In latter you find operator() and constraint function:
http://foam.sourceforge.net/docs/cpp/a00081.html
However in operator() code addSup does nothing according to:
Foam::basicSource::addSup

In case it was set to something else constraint clips it in a defined range.

March 5, 2013, 12:11	Questions about simplefoam	#1
maoyanren New Member Mao Mao Join Date: Feb 2013 Posts: 1 Rep Power: 0	Hi all, I am relatively new to OpenFOAM and I have a question about the solver simpleFoam. I am using OF 2.1.1. I read a little bit about the solver and algorithm and had some understanding of it. One thing confuses me though. In the source code of simpleFoam UEqn.H "tmp<fvVectorMatrix> UEqn ( fvm::div(phi, U) + turbulence->divDevReff(U) == sources(U) ); UEqn().relax(); sources.constrain(UEqn()); solve(UEqn() == -fvc::grad(p));" why is there a "sources(U)" term in the UEqn and it is even a function of U? And what is "sources.constrain(UEqn())" for? Any help will be appreciated.

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March 6, 2013, 02:16		#2
anishtain4 Senior Member Mahdi Hosseinali Join Date: Apr 2009 Location: NB, Canada Posts: 273 Rep Power: 18	Digging it in doxygen you first get to IObasicSourceList which is a derivative of IOdictionary and basicSourceList. In latter you find operator() and constraint function: http://foam.sourceforge.net/docs/cpp/a00081.html However in operator() code addSup does nothing according to: Foam::basicSource::addSup In case it was set to something else constraint clips it in a defined range.