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-   -   CyclicAMI: Problems with pressure field (http://www.cfd-online.com/Forums/openfoam-solving/107198-cyclicami-problems-pressure-field.html)

Thoma September 20, 2012 00:10

CyclicAMI: Problems with pressure field
 
1 Attachment(s)
Hello,

I am working with cyclicAMI boundary condition. But on the edges to other bcs I am getting weird results for the pressure field.
I have attached a screenshot to make my problem clear.

And that is the content of .../0/p:

PHP Code:

/*--------------------------------*- C++ -*----------------------------------*| =========                 |                                                 |
| \      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \    /   O peration     | Version:  2.0.1                                 |
|   \  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    
version     2.0;
    
format      ascii;
    class       
volScalarField;
    
object      p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 2 -2 0 0 0 0];

internalField   uniform 100000;

boundaryField
{
inlet
{
       
type            zeroGradient;
}
outlet
{
        
type            fixedValue
        
value           uniform 100000;
}
wall
{
        
type            zeroGradient;
}
vane
{
        
type            zeroGradient;
}
side1
{
        
type            cyclicAMI;
}
side2
{
        
type            cyclicAMI;
}
inject
{
       
type            zeroGradient;
}
sym
{
    
type        slip;
}
hole
{
        
type            zeroGradient;
}
vane_inflow
{
        
type            zeroGradient;
}


Does anybody know what is wrong in my simulation? Thank you very much for your help!!

Regards, Thomas

martyn88 September 21, 2012 09:20

I have a similar problem with my pressure field when I use cyclicAMI. Can I ask why you didn't just use cyclic conditions?

Thoma September 23, 2012 21:58

Hey,

the cyclic Boundary condition never worked for me in this model. I had always mismatching problems with the mesh. (I am using Salome 6.3 for the mesh generation). But with AMI it seemed to work. Though it looks like that OpenFoam sets some default boundary conditions on the edges.

Does anyone knows how to solve this issue?

javier_b November 14, 2012 04:41

Similar issue
 
Hey Thomas,
Did you manage to solve your problem? I am having a very similar issue.
Javier

shantan January 10, 2013 15:15

cyclicAMI pressure boundary
 
I have also the same problem! does somebody have any idea or could comment on it, if it would be a bug?!

Thoma January 10, 2013 15:34

Hey,

no sorry, I never solved the problem. I just neglected it in the end....

But let me know if you find a solution!

maHein January 11, 2013 18:17

I successfully used cyclicAMIs for turbomachinery flow simulation. I don't know, if you are using MRF. However, I experienced promblems when not correctly defining the "nonRotatingPatches" in the MRFDict.

sharonyue January 24, 2013 06:41

I am having a very similar issue too.....

prasant February 21, 2013 06:51

cyclicAMI for nonConformal meshes
 
Hello All,

Did anybody face an issue while using cyclicAMI on nonConformal Meshes?
My case is an impeller with volute also. Impeller is having pure Hexhedral and volute is having tetrahedral grid. I am giving cyclicAMI boundary condition for those interfaces.

I am giving mass flow at outlet and totalPressure at inlet.

By using the above settings, Mass is not balancing. The issue is, data is not transferring between these two interfaces. because of cyclicAMI.

And also Temperature values are not coming correct at outlet. Actually Ggi (OpenFOAM-1.6-Extd) is working fine with these settings. but here, Compressible solver with MRF is not available in this version. I modified the code. But there are some other issues.

So, Finally I came back to OpenFOAM current version (i.e) OF-2.1.1.

Please help me, If anybody success with cyclicAMI boundary conditon.

Regards
Prasant.

maHein February 21, 2013 12:04

Can you post your boundary file and the weithing factors for your case?

prasant February 22, 2013 04:51

Hello,

I am attaching my boundary file and weithing factors here:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.1.1 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class polyBoundaryMesh;
location "constant/polyMesh";
object boundary;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

8
(
r1-default
{
type wall;
nFaces 4176;
startFace 410703;
}
r1-hub
{
type wall;
nFaces 4914;
startFace 414879;
}
r1-inlet
{
type patch;
nFaces 864;
startFace 419793;
}
r1-shroud
{
type wall;
nFaces 4914;
startFace 420657;
}
s1-to-r1-side-2
{
type cyclicAMI;
nFaces 1008;
startFace 425571;
matchTolerance 0.0001;
neighbourPatch s1-to-r1-side-1;
transform noOrdering;

}
s1-default
{
type wall;
nFaces 16418;
startFace 426579;
}
s1-outlet
{
type patch;
nFaces 360;
startFace 442997;
}
s1-to-r1-side-1
{
type cyclicAMI;
nFaces 1926;
startFace 443357;
matchTolerance 0.0001;
neighbourPatch s1-to-r1-side-2;
transform noOrdering;

}
)

// ************************************************** *********************** //
and weithing factors are

Selecting thermodynamics package hPsiThermo<pureMixture<constTransport<specieThermo <hConstThermo<perfectGas>>>>>
AMI: Creating addressing and weights between 1008 source faces and 1926 target faces
AMI: Patch source weights min/max/average = 0.96403269, 1.0072789, 0.99952117
AMI: Patch target weights min/max/average = 0.83982674, 1.0035554, 0.99658895

Please view it and help me regarding this.

Thanks & Regards
Prasant

vitoco April 28, 2014 09:25

No solution
 
Hey Foamers...
Exactly the same here... and not solution. The edges take the pressure (atmospherical in my cases) and stays in a fixed value during all the simulation. This creates a non realistic field. Best regards,

Victor Mendoza

Ros May 9, 2014 10:05

Hi,

I am having the same problem with the pressure field. I already tested it on a straight channel with cyclicAMI and cyclic BC's. Only with the cyclic BC the pressure field is correctly calculated.

My geometry is similar to the geometry posted by Thomas. So in my case only cyclicAMI can work.

Does anyone have an idea what to do?

Thanks

student666 June 28, 2014 08:34

Hi all,

any news about cyclic AMI Problem?


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