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-   -   Continuity question??? (http://www.cfd-online.com/Forums/fluent/49336-continuity-question.html)

Jane September 24, 2008 11:36

Continuity question???
 
Why my continuity graph increase until Fluent show ERROR message?? what happen??

How to set Volume in Fluent??? for example set 5ml fluid for filling purpose.

anyone please help me...


joao September 25, 2008 02:28

Re: Continuity question???
 
Can you tell more details about what you are trying to simulate?

Jane September 25, 2008 02:40

Re: Continuity question???
 
Thank you for reply.

I'm simulating water filling to a gap between 2 plastic plate, it's capillary case. I use VOF and multiphase in my simulation.


joao September 25, 2008 03:45

Re: Continuity question???
 
What are your boundary conditions?

Jane September 25, 2008 03:51

Re: Continuity question???
 
rectangular plates: 1 inlet= velocity inlet 3 outlet= outflow

any suggestion about boundary conditions. thanks

joao September 25, 2008 04:04

Re: Continuity question???
 
I can't see exactly what your simulation is like, but I can give you some general advices:

1. Check your grid in Fluent. 2. Check your case. This will tell you if there is something wrong with your setup.

If you don't have any problems with the above, then you should run your simulation for 10-20 iterations, and then check the mass residuals by contour plots or whatever, to see where are you having problems.

Cheers

Jane September 25, 2008 04:09

Re: Continuity question???
 
Thanks. i will try it.

max September 25, 2008 09:25

Re: Continuity question???
 
Hi Jane,

as far as i know, outflow Bc, i.e. a zero gradient condition is not applicable for VOF-Simulations. Switch to pressure outlet and make sure that only one phase can enter here if back flow occures.

cheers

max

Jane September 25, 2008 21:02

Re: Continuity question???
 
Thank you max.

I have tried using pressure outlet, but i found the problem that reversed flow in my filling simulation.

May i know how to make sure only 1 phase enter??

Thank you


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