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-   -   can any body give me an answer about the notice (http://www.cfd-online.com/Forums/main/83349-can-any-body-give-me-answer-about-notice.html)

wwwuxing December 24, 2010 04:19

can any body give me an answer about the notice
 
when i calculate the cavitation of a valve, the slover give the notice like this:


****** Notice ****** |
| A wall has been placed at portion(s) of an OUTLET |
| boundary condition (at 77.9% of the faces, 69.6% of the area) |
| to prevent fluid from flowing into the domain. |
| The boundary condition name is: outlet. |
| The fluid name is: yetai shui. |
| If this situation persists, consider switching |
| to an Opening type boundary condition instead


i have extended the outlet pipe and give the outlet as opening conditions, but is still shows the notice, who can help me?

bhatiadinesh December 24, 2010 06:53

First try continuing for some iterations, the notice might go away, but if it still doesn't go, there is some problem in setting up the problem or the boundary condition.

Some times in a diffusing flow, initially as the flow develops this kind of notice is produced. Are you simulating some pump, compressor or diffuser ?

-Dinesh

wwwuxing December 25, 2010 23:55

1 Attachment(s)
Quote:

Originally Posted by bhatiadinesh (Post 288377)
First try continuing for some iterations, the notice might go away, but if it still doesn't go, there is some problem in setting up the problem or the boundary condition.

Some times in a diffusing flow, initially as the flow develops this kind of notice is produced. Are you simulating some pump, compressor or diffuser ?

-Dinesh


thanks for you reply, i try continuing more iterations, but it does not works., but i amend the outlet conditions, the notice disappear, but the contour of the water volume fraction shows the simulations is not reasonable, My simulation is a control valve in the attachment, the left is inlet and the velocity is 12m/s, the outlet in right and is set to opening, the ralative pressure is 30000pa.


The image of the volume fraction shows it is impossible that the cavatation is too deep. The fluid is water.


who can give me an explanation of that?


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