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-   -   Weird result in simulation of Taylor-Couette Flow (https://www.cfd-online.com/Forums/openfoam-solving/185078-weird-result-simulation-taylor-couette-flow.html)

amin.z March 18, 2017 09:53
Weird result in simulation of Taylor-Couette Flow
 
3 Attachment(s)
Hi everybody,

I have recently immigrated from Fluent to OpenFOAM, so maybe this question looks weird :)
I'm solving classic flow of Taylor-Couette (the flow in narrow gap of two rotating concentric cylinders). The results of simulation in Fluent are exactly what I was expecting, but OpenFOAM gives strange results, as you can see in the attached photos. The vectors are slices of the 3D domain, the inner cylinder is rotating with 0.6 rad/sec and the outer one is fixed. As it's apparent from the photos there's a linear velocity for the outer cylinder which is certainly wrong. there's no inlet/outlet BC, the BC for the inner cylinder is rotatingWallVelocity and the BC for the top and bottom faces is symmetry.

Any idea is appreciated

fumiya March 19, 2017 02:35
You might want to check the velocity boundary condition on the outer cylinder.
Is it fixed to (0 0 0)?

Best regards,
Fumiya

amin.z March 19, 2017 06:41
Tnx for ur reply, actually I also changed the BC for outer cylinder to rotatingWallVelocity with zero angular velocity to force the wall to be stationary, but the results are still the same, here is the U BC for ur consideration

Code:
    top
    {
        type            symmetry;
    }

    innerwall
    {
        type            rotatingWallVelocity;
        origin          (0 0 0);
        axis            (0 0 1);
        omega          0.6;
    }

    outerwall
    {
        type            rotatingWallVelocity;
        origin          (0 0 0);
        axis            (0 0 1);
        omega          0;
    }

    bottom
    {
        type            symmetry;
    }

fumiya March 20, 2017 01:32
Could you upload your case?

Best regards,
Fumiya

amin.z March 21, 2017 08:53
yeah, sure,
please find the case using the link below:

https://www.dropbox.com/s/87849pj5aecdtvh/OpenFOAM.tar.gz?dl=0

sati March 21, 2017 10:05
Hi,
I could be wrong, but it looks like a visualisation problem from paraview.

Have you enabled the "scale mode" option in the glyphs options of paraview?

amin.z March 21, 2017 10:39
1 Attachment(s)
Quote:
Originally Posted by sati (Post 641595)
Hi,
I could be wrong, but it looks like a visualisation problem from paraview.

Have you enabled the "scale mode" option in the glyphs options of paraview?
Good point, actually I was leaving this option with the default value "off";
but when I change it to "vector" the vectors get rational. I think since I wanna visualize vectors of velocity, I have to select this one in "scale mode"


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