[keepfit]

Hi Foamers,

I have few questions on the UEqn in OpenFoam:

e.g.

1. understandable UEqn in pisoFoam

fvVectorMatrix UEqn
(
fvm::ddt(U)
+ fvm::div(phi, U)
+ turbulence->divDevReff(U)
);

and

if (momentumPredictor)
{
solve(UEqn == -fvc::grad(p));
}

so the full equation for U is:

fvm::ddt(U)+ fvm::div(phi, U) + turbulence->divDevReff(U) == -fvc::grad(p)

2. confused with this UEqn in pimpleFoam (OF 2.2.2), namely the ' ==':

tmp<fvVectorMatrix> UEqn
(
fvm::ddt(U)
+ fvm::div(phi, U)
+ turbulence->divDevReff(U)
==
fvOptions(U)
);

and

if (pimple.momentumPredictor())
{
solve(UEqn() == -fvc::grad(p));
fvOptions.correct(U);
}

So in this case the full equation is ??

fvm::ddt(U)+ fvm::div(phi, U) + turbulence->divDevReff(U)
== fvOptions(U)
== -fvc::grad(p)

but this seems not logical, should it be like this?

fvm::ddt(U)+ fvm::div(phi, U) + turbulence->divDevReff(U) - fvOptions(U)
== -fvc::grad(p)

Why is there a '==' in the UEqn ?


Cheers,

Daivd

[bieshuxuhe]

hi,
you could watch this .

http://www.cfd-online.com/Forums/openfoam-programming-development/85013-operator.html

it is a little long to read , but you could understand the "==" well after reading!


best wish
xuhe

[keepfit]

Originally Posted by bieshuxuhe

hi,
you could watch this .

http://www.cfd-online.com/Forums/openfoam-programming-development/85013-operator.html

it is a little long to read , but you could understand the "==" well after reading!


best wish
xuhe

thanks xuhe, I will look to that post.