[majidsvn7]

Hi, in the description of simpleFoam solver have been written for steady state case but If i want to use simple algorithm for transient problem, which solver is proper than others?!

[allenjohngeorge]

simpleFoam is a steady state solver. You can use pimpleFoam for solving transient problems.


If you want to use simple algorithm for transient problems, then to will have to modify the source code of simpleFoam and make new solver by including the time derivative term also.


simpleFoam U.Eqn
{
fvm::div(phi, U)
+ turbulence->divDevReff(U)
==
fvOptions(U)
}


pimpleFoam U.Eqn
{
fvm::ddt(U)
+ fvm::div(phi, U)
+ turbulence->divDevReff(U)
==
fvOptions(U)
}

you can see that the time derivative term is absent in simpleFoam


So if you want to use it for transient, you have to include the time derivative terms both in U.Eqn and p.Eqn and rebuild the solver. Always try to make a copy the existing solver edit it and rename the new solver. Do not make any changes in the existing solvers.



The procedures to be followed while modifying solver are dicussed in other threads. check that too.

[majidsvn7]

Thank you for comprehensive reply,but I think the pimpleFoam solver is suitable for dynamic mesh.but my problem is not, Can I use this solver for non-dynamic mesh geometries?!

[allenjohngeorge]

Yes, pimpleFoam can be used only for non-dynamic meshes.


For dynamic meshes you have to use pimpleDymFoam.


Check the userguide of openfoam to know the usage of each solver. It is clearly mentioned there the conditions at which each solver can be used.