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-   -   Choosing a solver. (https://www.cfd-online.com/Forums/openfoam/211073-choosing-solver.html)

DANIEL NDIRANGU November 12, 2018 06:10

Choosing a solver.
 
I am a complete beginner. I am trying so simulate water flow in a simple y pipe whose branches are 90° apart. I have already drawn the geometry in Salome and exported it to Openfoam in unv format. I used ideasUnvToFoam to make it openFoam compatible. I tried using icoFoam but I got errors. I suspect it's the boundary conditions in the u and p files. Anyone with a tip on how to go about this? Thanks

RobertHB November 12, 2018 07:59

Quote:

Originally Posted by DANIEL NDIRANGU (Post 714938)
Anyone with a tip on how to go about this? Thanks

Hey Daniel,
as in most cases when you want a helpful answer, provide more details. We know you tried icoFoam but failed, but what did the error message say? Do you try to simulate a transient flow or a steady one? Which boundary conditions do you use? Which fvSolution settings and which fvSchemes settings?

If you provide at least these infos you might get a more detailed answer and in a less amout of time. Either upload your files as an attachment or post their content in [code*][*/code] brackets (without the *).

DANIEL NDIRANGU November 16, 2018 03:53

Thanks Robert.

I have attached a screenshot of the error message. I tried to simulate a transient flow. My boundary conditions were; Pressure Boundary Conditions(Inlet- fixedValue, Outlet-fixedValue, walls-zeroGradient) and Velocity Boundary Conditions(Inlet-pressureInletVelocity, Outlet-zeroGradient, Walls-fixedValue). As for the fvsolution and fvSchemes settings, what settings are appropriate for my case? I run my simulation with the fvsolution and fvschemes as copied directly from the cavity case in icoFoam.

Any help or correction will be appreciated. I am an undergrad doing my final year project and I need to use openfoam

BM_CFD November 16, 2018 06:01

Your screenshot is not shown here. You can use command icoFoam > log.Error and this will create a file named as log.Error. You can post that error in here then we can see your problem. I suspect that your problem is related to the boundary file located in the constant/polyMesh directory. After you converged your mesh into the OpenFOAM format, you should look into your boundary file. Name of your boundaries in 0/U and 0/p must be same with the boundary file in the constant directory.


Batu

RobertHB November 16, 2018 06:03

Quote:

Originally Posted by DANIEL NDIRANGU (Post 715804)
Thanks Robert.

I have attached a screenshot of the error message. I tried to simulate a transient flow. My boundary conditions were; Pressure Boundary Conditions(Inlet- fixedValue, Outlet-fixedValue, walls-zeroGradient) and Velocity Boundary Conditions(Inlet-pressureInletVelocity, Outlet-zeroGradient, Walls-fixedValue). As for the fvsolution and fvSchemes settings, what settings are appropriate for my case? I run my simulation with the fvsolution and fvschemes as copied directly from the cavity case in icoFoam.

Any help or correction will be appreciated. I am an undergrad doing my final year project and I need to use openfoam

Hi Daniel,
i can't see you screenshot, but we can start with the the more obvious parts:
Pressure boundary condition: Inlet shoud be zeroGradient, while the outlet ist fixedValue.
Velocity: For your outlet try:

Code:

    outlet
    {
        type            inletOutlet;
        inletValue      uniform (0 0 0);
        value          uniform (0 0 0);
    }


DANIEL NDIRANGU November 24, 2018 02:32

Hello guys,
Sorry for not getting back earlier but Robert's solution worked. I had edited the boundary file incorrectly.
Thanks a lot


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