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-   -   tank sloshing overflow error (http://www.cfd-online.com/Forums/cfx/84092-tank-sloshing-overflow-error.html)

enghamed January 20, 2011 00:34

tank sloshing overflow error
 
I have modeled a recetangular tank with a unit thickness (2D) and runs well but when I change the mesh to cylinder tank (3D) with all the same conditions for the 2D, I get fatal overflow error!!!
why is this happening? what should I do?

ghorrocks January 20, 2011 05:19

Can you describe what you are doing a bit better?

But the problem is probably mesh quality.

enghamed January 20, 2011 21:38

I want to model water sloshing in a cylinder tank.
As a first attempt I modeled a rectangular tank with two faces of symetry and the top as open and the other three faces as wall. Defined the mesh displacment for the wall as x=Asinwt. It ran very good.
Now i change the goemetry with a cylindrecal tank and didn't change any settings, but now i get error of "Floating point exception: Overflow".
I have meshed the goemetry in ICEM with an o-grid.
any more details you need?

enghamed January 21, 2011 01:37

I now tried a 3D rectangular and agian got the overflow error.
It shouldn't be the quality of the mesh since now I have a complete square hex elements!
Have u got any idea what is going wrong?

regards

ghorrocks January 21, 2011 07:28

No idea what is wrong.

Add the physics into the model one step at a time. Does the 3D model work with a static mesh, but the initial free surface deformed somehow to start a motion? Does the model work with a motion of a small magnitude?

zcesd47 June 24, 2011 13:55

hi,enghamed
I am now modeling a case very similar to your one, the water sloshing in a rectangular tank, I use two domains one as water and the other as air, and applied the displacement sin(wt) to the walls of the tanks. initial condition for air domain volume fraction air= 1& volume fraction water =0. The contrast for water domain. But when I try to solve it, the solver terminate at the 1st timestep, the linear solution for U-mom V-mom and P-vol failed. I change my B.C and timesteps but doesn't help. Do you have any suggestions for my problem. Could you tell me how you set you interface and initial conditions. Very much appreciated.

Regards

Dijun

ghorrocks June 25, 2011 06:50

Do the tutorial free surface flow over a bump for ideas of how to set up and run free surface models.

zcesd47 June 25, 2011 13:19

Thank you . It seems that I define the Buoyancy ref. density as Water's density instead of air's.


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