# convergence in interFoam

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January 2, 2011, 12:37
convergence in interFoam
#1
Senior Member

Nima Samkhaniani
Join Date: Sep 2009
Location: Tehran, Iran
Posts: 1,264
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Rep Power: 20
hi foamer
i made a simulation with interfoam, my simulation reached steady state, but i cant understand why alpha residual is growing? is there any problem? is my simulation correct?
as i know for a converge solution residual should be decreasing , whats wrong ?
Attached Images
 alpha1Re.jpg (19.6 KB, 148 views)

 January 4, 2011, 17:30 #2 Senior Member   Kent Wardle Join Date: Mar 2009 Location: Illinois, USA Posts: 218 Rep Power: 17 Sorry, but you haven't given enough information for anyone to be able to offer a useful explanation of what you are seeing. Please be sure to include details such as what version of the code you are using, what is your problem setup INCLUDING BOUNDARY CONDITIONS, etc. Just off-hand, I might take a stab and guess that you are running a simulation with no outlets?

 January 8, 2011, 02:31 #3 Senior Member   Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,264 Blog Entries: 1 Rep Power: 20 hi dear friend openFoam 1.6.x axisymetric mesh with cyclic boundary condition for u and alpha and with pressure jump for p in inlet and out let and axis is empty and wall!!! for remained side and wedge type for back and front!!! so you think that because i have cyclic condition? does it make any problem for simulation?

January 24, 2011, 13:55
detailed information
#4
Senior Member

Nima Samkhaniani
Join Date: Sep 2009
Location: Tehran, Iran
Posts: 1,264
Blog Entries: 1
Rep Power: 20
hello friend
i encounter problem in interFoam convergence in modelling of bubble train flow in tube. domain is axismetric, and use cyclic condition for p,u and alpha. mean pressure gradient is fixed. look below :

alpha :

boundaryField
{

front
{
type wedge;
}

back
{
type wedge;
}

fixedWall
{
}

inletOutlet
{
type cyclic;

}

axis
{
type empty;
}

}

pressure :
boundaryField
{
front
{
type wedge;
}
back
{
type wedge;
}
fixedWall
{
type buoyantPressure;
value uniform 0;
}

inletOutlet
{

type fan;
patchType cyclic;
f List<scalar> 1 (3400);
value uniform 0;
}

axis
{
type empty;
}

U:
boundaryField
{
front
{
type wedge;
}
back
{
type wedge;
}

fixedWall
{
type fixedValue;
value uniform (0 0 0);
}

inletOutlet
{
type cyclic;
value uniform (0 0 0);
}

axis
{
type empty;
}
}

i used different grid size, and increased alpha correction and alpha sub cycle but i could not find reasonable alpha residual! although pressure residual is constant not decreasing! after correction, pressure residual reduces but it oscillates.
Attached Images
 alpha.jpg (27.7 KB, 111 views) alphaResidual.jpg (29.8 KB, 76 views) pressureResidual.jpg (32.5 KB, 63 views) pressure.jpg (41.4 KB, 99 views) pressureResidualAfterCorrection.jpg (88.0 KB, 72 views)

 February 9, 2011, 13:56 #5 Senior Member   Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,264 Blog Entries: 1 Rep Power: 20 any suggestion please?

 Tags convergance, interfoam