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-   -   Stripes close to my Inlet BC in OpenFOAM (http://www.cfd-online.com/Forums/openfoam/116079-stripes-close-my-inlet-bc-openfoam.html)

Joachim April 12, 2013 10:48

Stripes close to my Inlet BC in OpenFOAM
 
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Hello everyone!

I am trying to simulate the flow over a laminar flat plate (1 meter long). I am using standard values for the air (nothing crazy...), and a velocity of 0.1 m/s (solver -> icoFoam).

I only have one problem: the flow close to the inlet boundary is really strange, as can be seen in the attached figure. I thought this would be due to my boundary conditions, so I tried different types: fixedValue / inletOutlet / pressureInletVelocity and pressureInletOutletVelocity. Nothing worked! I always have these stripes on the left (except in the pressureInletVelocity case, where the stripes disappear, but the velocity is clearly wrong in the tangential direction. It increases linearly with distance from the bottom plane over the whole domain).

I also tried to modify the outlet and top boundaries, but nothing worked! Would anyone have an idea on how to solve this problem? I would be extremely grateful!
Thank you very much,

Joachim

fumiya April 12, 2013 21:55

What scheme do you use for the convection term?
I think the setting "div(phi,U) Gauss linear" could be the cause of the problem.

P.S. You might want to try the simpleFoam solver for steady simulations.

Best regards,
Fumiya

Joachim April 17, 2013 12:54

Oh sorry, it seems that I posted this thread at the wrong place.
Thank you for your answer. I modified the discretization scheme for the divergence term, but nothing changed. As you suggested, I used simpleFoam instead of icoFoam, and everything worked just fine. This is strange, I thought that unsteady simulations were inherently more stable than steady simulations...


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