[Hiroshiman]

Originally Posted by cliff

Sorry i posted the same question. as i wanted to run one of viscoelastic tutorial, i came up with this error
/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.3.1 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 2.3.1-bcfaaa7b8660
Exec : blockMesh
Date : Jan 28 2015
Time : 20:14:15
Host : "sepinood-Inspiron-N5010"
PID : 27458
Case : /opt/openfoam231/tutorials/viscoelastic/viscoelasticFluidFoam/DCPP/constant/polyMesh
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time



--> FOAM FATAL IO ERROR:
cannot find file

file: /opt/openfoam231/tutorials/viscoelastic/viscoelasticFluidFoam/DCPP/constant/polyMesh/system/controlDict at line 0.

From function regIOobject::readStream()
in file db/regIOobject/regIOobjectRead.C at line 73.

FOAM exiting
i would appreciate your help. thanks

I believe you're not in the good directory.

[cliff]

Would you help me Hiroshiman casue im new on OpenFoam

[Hiroshiman]

Originally Posted by cliff

Would you help me Hiroshiman casue im new on OpenFoam

Here is all you need to start:
http://www.openfoam.org/docs/user/

[cliff]

Hi foamers. i want to simulate a viscoelastic fluid flow but i dont know which extension is appropriate for this 1.6ext or 3.1. i could not find any instruction for 1.6 on ubuntu 14.04. can anyone help me?

[wyldckat]

Originally Posted by cliff

Hi foamers. i want to simulate a viscoelastic fluid flow but i dont know which extension is appropriate for this 1.6ext or 3.1. i could not find any instruction for 1.6 on ubuntu 14.04. can anyone help me?

Quick answer: Install foam-extend 3.1, which is the latest version. Instructions available here: http://openfoamwiki.net/index.php/In...oam-extend-3.1

[cliff]

Thank you so much Bruno and Hirosiman

[cliff]

Hi Foamers.
Me again. i've already installed foam-extend 3.1 and viscoelastic tutorials run well. but when i change the geometry and update the boundaries of u,p,tau and phi with my new geometry this error shows up: "--> FOAM FATAL IO ERROR:
keyword bottom_wall is undefined in dictionary "/home/sepinood/foam/foam-extend-3.1/tutorials/viscoelastic/viscoelasticFluidFoam/Leonov_2/0/p::boundaryField"

file: /home/sepinood/foam/foam-extend-3.1/tutorials/viscoelastic/viscoelasticFluidFoam/Leonov_2/0/p::boundaryField from line 25 to line 45.
"
Note that i generated the geometry and mesh with Gambit and imported in tutorial case with fluentMeshToFoam command.
These are my boundary and P file.
p

dimensions [0 2 -2 0 0 0 0];

internalField uniform 0;

boundaryField
{
cylinder
{
type zeroGradient;
}
top_wall
{
type zeroGradient;
bottom_wall
{
type zeroGradient;
}
outlet
{
type fixedValue;
value uniform 0;
}
inlet
{
type zeroGradient;
}
frontAndBack
{
type empty;
}
}




boundary
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | foam-extend: Open Source CFD |
| \\ / O peration | Version: 3.1 |
| \\ / A nd | Web: http://www.extend-project.de |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class polyBoundaryMesh;
location "constant/polyMesh";
object boundary;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

6
(
cylinder
{
type wall;
nFaces 46;
startFace 7609;
}
top_wall
{
type wall;
nFaces 45;
startFace 7655;
}
bottom_wall
{
type wall;
nFaces 45;
startFace 7700;
}
outlet
{
type wall;
nFaces 45;
startFace 7745;
}
inlet
{
type wall;
nFaces 45;
startFace 7790;
}
frontAndBackPlanes
{
type empty;
nFaces 7722;
startFace 7835;
}
)

[adambarfi]

dear mojtaba,

you didn't close the bracket in top_wall boundary:

p

dimensions [0 2 -2 0 0 0 0];

internalField uniform 0;

boundaryField
{
cylinder
{
type zeroGradient;
}
top_wall
{
type zeroGradient;
}
bottom_wall
{
type zeroGradient;
}
outlet
{
type fixedValue;
value uniform 0;
}
inlet
{
type zeroGradient;
}
frontAndBack
{
type empty;
}
}

[cliff]

Originally Posted by adambarfi

dear mojtaba,

you didn't close the bracket in top_wall boundary:

p

dimensions [0 2 -2 0 0 0 0];

internalField uniform 0;

boundaryField
{
cylinder
{
type zeroGradient;
}
top_wall
{
type zeroGradient;
}
bottom_wall
{
type zeroGradient;
}
outlet
{
type fixedValue;
value uniform 0;
}
inlet
{
type zeroGradient;
}
frontAndBack
{
type empty;
}
}

Thank you Snowman .

[cliff]

Hi dear foamers. I've simulated a viscoelastic fluid with leonov model in a sudden expansion geometry in OF but i am not sure about the final results. I just want to know if there is any source to validate my data. and if any of you foamers have encountered with this problem or maybe solved it, i really want to know how. note that i'm using OF231 and foam-extend 3.1. these are my final results:


p.jpg

sigma.jpg

u.jpg

tau.jpg

[adambarfi]

Are you sure your solution is converged? it seems that there are some problems in convergence. what are the boundary conditions?

[cliff]

Originally Posted by adambarfi

Are you sure your solution is converged? it seems that there are some problems in convergence. what are the boundary conditions?

Hi Mostafa. I'm new at openfoam and don't know much about convergence. Could you please explain more?
so these are my boundaries for P and U.
P
dimensions [0 2 -2 0 0 0 0];

internalField uniform 0;

boundaryField
{
inlet
{
type zeroGradient;
}
bottom
{
type zeroGradient;
}
top
{
type zeroGradient;
}
bottexp
{
type zeroGradient;
}
topexp
{
type zeroGradient;
}
top2
{
type zeroGradient;
}
bottom2
{
type zeroGradient;
}
outlet
{
type fixedValue;
value uniform 0;
}
frontAndBack
{
type empty;
}
}



U

dimensions [0 1 -1 0 0 0 0];

internalField uniform (0 0 0);

boundaryField
{
inlet
{
type fixedValue;
value uniform (0.03875 0 0);
}
bottom
{
type zeroGradient;
}
top
{
type zeroGradient;
}
bottexp
{
type zeroGradient;
}
topexp
{
type zeroGradient;
}
top2
{
type zeroGradient;
}
bottom2
{
type zeroGradient;
}
outlet
{
type zeroGradient;
}
frontAndBack
{
type empty;
}
}

[adambarfi]

Dear Mojtaba,

Why did you use zero gradient velocity condition on your walls? can you tell me clearly what are u modeling?

you can plot the residuals or you can save them in a log file and then see how the residuals change and if your solution is going to converge or not. you should specify a convergence criterion in fvSolution file.

for plotting residuals see the below link;
http://www.cfd-online.com/Forums/ope...tml#post238091

Regards,
Mostafa

[cliff]

Originally Posted by adambarfi

Dear Mojtaba,

Why did you use zero gradient velocity condition on your walls? can you tell me clearly what are u modeling?

you can plot the residuals or you can save them in a log file and then see how the residuals change and if your solution is going to converge or not. you should specify a convergence criterion in fvSolution file.

for plotting residuals see the below link;
http://www.cfd-online.com/Forums/ope...tml#post238091

Regards,
Mostafa

Hi Mostafa and thank you for your help. I just want to simulate a viscoelastic fluid flow with Leonov or any other models in a sudden expansion geometry with the ratio of 1:3 and observe the resulting vortexes, but unfortunately don't know much about boundary conditions and convergence. could you please tell me in details what am i missing in boundary conditions or what type of boundaries should i use?
Thanks

[adambarfi]

Originally Posted by cliff

Hi Mostafa and thank you for your help. I just want to simulate a viscoelastic fluid flow with Leonov or any other models in a sudden expansion geometry with the ratio of 1:3 and observe the resulting vortexes, but unfortunately don't know much about boundary conditions and convergence. could you please tell me in details what am i missing in boundary conditions or what type of boundaries should i use?
Thanks

Dear Mojtaba,

If you have a non-slip boundary conditions on your walls so you should specify a zero velocity at each wall. for example:

boundaryField
{
    floor
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }
.
.
.

and it is supposed to read more papers about the subject and then start simulating with enough information.

Regards,
Mostafa

[2vdba2]

Does anyone know how to install viscoelasticfluidfoam on the latest openfoam 3.01??

[sita]

Hi,

I haven't used viscoelasticFluidFoam in a while, but as far as I'm aware, it's part of the OpenFOAM-Extend project: http://www.extend-project.de
So if you install OpenFOAM-Extend (instead of, or next to OpenFOAM), viscoelasticFluidFoam should automatically be installed as part of that.

Good luck,
Sita

[mehdi kamyabi]

Hi Foamers,
I was a user of viscoelasticfluidfoam about 3 years ago but recently have no experience with openfoam. my question is how can I implement a two-phase VOF simulation with Openfoam? is there any released solver which can do it without many difficulties? in addition do anybody know about the existence of this ability in any other softwares like polyflow?
Thanks.

[alqayssi69]

hello Jovani.
Thank you very much Jovani . these information very helpful . please can you help me in fitting experimental data of flow curve for polymeric melt.

Regard

[Julya_Shmit]

Hello foamers !

I need your help.
I am trying to implement a pressure driven 2D flow in channel with Giesekus model.
Geometry, model's parameters and boundary conditions in Geometry.png.

My analytical solutions give a great shear thinning (very big shear rate) near boundary/fixedWalls but I cann't achieve this results in OpenFOAM. To be more exact a velocity profile begins to become a desirable form with big shear rate near fixedWalls (velocity.pdf) BUT the solution diverges. And I cann't reach a quantitative accordance. The residual graphic is in Residual.pdf

The question is 1) why the problem diverges; 2) how can I avoid it?

May be somebody can give me the cue.... I will be happy