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dak56 December 10, 2008 11:32

CFX 11 Solver problem
| ****** Notice ****** | | A wall has been placed at portion(s) of an OUTLET | | boundary condition (at 98.5% of the faces, 93.8% of the area) | | to prevent fluid from flowing into the domain. | | The boundary condition name is: outlet. | | The fluid name is: Air at 25 C. | | If this situation persists, consider switching | | to an Opening type boundary condition instead. | +--------------------------------------------------------------------+

+--------------------------------------------------------------------+ | ERROR #004100018 has occurred in subroutine FINMES. | | Message: | | Fatal overflow in linear solver.

Can't solve this problem. Tried everything but nothing helps. What can be wrong?

Timon December 10, 2008 12:01

Re: CFX 11 Solver problem
Without any details of your simulation this can be caused by a number of things. The message simply means there is nearly no outflow over your outlet, so your setup is incorrect. This could be caused by physics (eg. imposed outlet static pressure too high), an improper choice of the location of the outlet (eg. vortices convecting over the boundary --> extend your domain), or simply instabilities associated with startup (try a smaller timestep/local timestepping etc.).

mic December 11, 2008 12:36

Re: CFX 11 Solver problem
What timon says is correct, but first of all I would try to extend the outlet (3-4 times the diameter and run it again. You can verify in the post-processor if you have vortex at the outlet.

Glenn Horrocks December 11, 2008 20:20

Re: CFX 11 Solver problem

It is a warning, not an error. All it is saying is that there is some reverse flow at an outlet and it has been stopped as reverse flow is not allowed at outlets. If the effect of this reverse flow is not significant then you can ignore the error and continue. If the reverse flow is significant you should (in increasing order of accuracy):

1) Replace it with an opening which allows reverse flow 2) Extend your domain so the new outlet location has flow in one direction only

And you should check your domain physics to check that is OK.

Glenn Horrocks

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