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-   -   2D simpleFoam simulation gets stuck - no error - problem with boundaries? (http://www.cfd-online.com/Forums/openfoam/90529-2d-simplefoam-simulation-gets-stuck-no-error-problem-boundaries.html)

lovecraft22 July 13, 2011 05:14

2D simpleFoam simulation gets stuck - no error - problem with boundaries?
 
Hi all;
trying to run a simple 2D circular cylinder.

I have already run that but I got a 3D resulting field so I slightly changed the boundary conditions and now the simulation gets stuck without any error at:

Code:

Time = 1

smoothSolver:  Solving for Ux, Initial residual = 0.407396, Final residual = 0.0155929, No Iterations 3
smoothSolver:  Solving for Uy, Initial residual = 0.485038, Final residual = 0.0173646, No Iterations 3

What you think could be the problem?
Maybe something related to my boundaries?

Thank you!

Lorenzo

lovecraft22 July 13, 2011 05:16

Update: I think it blows up and I get a floating point excepion…

Any help would be really appreciated!

Eren10 July 13, 2011 05:37

set-up normal files for BC , especially for U and p. I dont see why you are using complicates structure of the files, look to the tutorials

lovecraft22 July 13, 2011 07:32

Thank you Eren.

What do you mean with "Complicate file structure"?

lovecraft22 July 13, 2011 12:59

Ok, I simplified the boundary conditions for U and p (which I copied from the motorbike tutorial and that's why they were a little bit complicated).

Now, what should I set for the turbulence model (K-e) conditions?

lovecraft22 July 13, 2011 16:37

1 Attachment(s)
Eventually I managed to solve the case but I got a 3D solution instead of a 2D one, as you can see from the pressure plot on the surface:
http://dl.dropbox.com/u/2459663/cilindro_2d.png

What may the problem be?

Thank you!

Eren10 July 14, 2011 09:58

you want to simulate a 2D, so x and y . In the z direction only a one cell is required. if we asume x y forms the circular shape of the cylinder, than the domains parallel to the x- y plane should be empty.

lovecraft22 July 14, 2011 10:14

Tank you eren. If you look at my case directory you'll see that I already have only ove cell in z direction and both the planes perpendicular to the z-axis are already set as empty...

Eren10 July 14, 2011 10:28

I have no experience with the openfoam's way of generating the object, I am using an other program for mesh. so I cant help you. But make the distance in the z direction very small. but if that is oke, make a paint figure of the inlet outlet conditions etc.. in 2D, than we can check the BC.

lovecraft22 July 14, 2011 12:05

Inlet and outlet conditions (e.g. pressure) are perfectly 2D…

lovecraft22 July 15, 2011 13:51

I think I'll open another topic for this problem, since it's quite different from the one I started this topic for.


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