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Mixture Model Turbulent Flow Slip Velocity

Posted Mar 29, 2011, 1:33 p.m. EDT 5 Replies

Rui Silva
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Hi folks.

I have a bit of a problem with MM Turbulent Flow.

After modelling solid liquid homogeneous flow, I can seem to understand how to model the heterogeneous flow.

After reading the manual, I want to use define a SLIP Model.

However I have some doubts about this.

Since it is an implict situation, how do i define this??

Do i need to give an initial estimate?

If someone has some experience or insight, or even provide an example I would appreciate it.
I have attached a file that I used for homogeneous flow.
Hope someone can help.

Cheers!

Attachments:

5 Replies Last Post Apr 15, 2011, 10:23 a.m. EDT
Rui Silva
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Posted: 1 decade ago Mar 29, 2011, 4:48 p.m. EDT
OK.

I managed to get some advance but I keep getting this error:

Error-Failed to find consistent initial values

I don't understand why this happens...

The file is attached.

Hope someone can help.

Thanks.

Cheers.
OK. I managed to get some advance but I keep getting this error: Error-Failed to find consistent initial values I don't understand why this happens... The file is attached. Hope someone can help. Thanks. Cheers.

Attachments:

Rui Silva
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Posted: 1 decade ago Mar 30, 2011, 4:22 a.m. EDT
Anyone?
Anyone?
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Apr 7, 2011, 4:01 a.m. EDT
Hi

I do not know if you have found your way out, but in the latest 4.1.0.185, if you clear your solution and run it with a new solver setup (+ removes the stationary case) it seems to solve, but I do not know if its correct ;) the diffusion seems to be very slow

--
Good luck
Ivar
Hi I do not know if you have found your way out, but in the latest 4.1.0.185, if you clear your solution and run it with a new solver setup (+ removes the stationary case) it seems to solve, but I do not know if its correct ;) the diffusion seems to be very slow -- Good luck Ivar
Rui Silva
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Posted: 1 decade ago Apr 7, 2011, 1:44 p.m. EDT
Hello Ivar,

after contacting Support, they informed that there was a bug with the V4.0a with the slip velocity models.

It was likely that were was not going to be a convergence, due to that particular bug.

So I went back to 3.5a and I did get some results, although I am struggling with the mesh density and
the Solvers.

If you could please upload the modified file, I would be gratefull.

I have recently acquired the 4.1 version.

Thank you very much for your input.

Rui
Hello Ivar, after contacting Support, they informed that there was a bug with the V4.0a with the slip velocity models. It was likely that were was not going to be a convergence, due to that particular bug. So I went back to 3.5a and I did get some results, although I am struggling with the mesh density and the Solvers. If you could please upload the modified file, I would be gratefull. I have recently acquired the 4.1 version. Thank you very much for your input. Rui
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Apr 15, 2011, 10:23 a.m. EDT
Hi

take your 14.mph model above, open it in the updated (for me v4.1.0.185) COMSOL session.

Select Solver Configuration, right click "Delete Solvers" then Solve.

To have no errors, even when testing initial conditions, add a "Parameter" t= 0[s] as you refer to "t" and t is only there from the moment the stationary solver acts

I did nothing else and havent stored the file

--
Good luck
Ivar
Hi take your 14.mph model above, open it in the updated (for me v4.1.0.185) COMSOL session. Select Solver Configuration, right click "Delete Solvers" then Solve. To have no errors, even when testing initial conditions, add a "Parameter" t= 0[s] as you refer to "t" and t is only there from the moment the stationary solver acts I did nothing else and havent stored the file -- Good luck Ivar

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