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-   -   Unsteady state case setup (http://www.cfd-online.com/Forums/fluent/30926-unsteady-state-case-setup.html)

Christian February 12, 2003 12:00

Unsteady state case setup
 
I am trying to simulate a tubeflow where the velocity is approx. 20m/s and at the time "t" a pressure rise in the middle of this tube occurs. This pressure rise is only happening once.

How do I make the setup? This case is only a test case to get to know the setup parameters and to learn, so if you need any information for your answer, please just make some up. The important case information is the pressure rise in the middle of the tube.

Any answers are welcome.

Christian

heydari February 15, 2003 03:15

Re: Unsteady state case setup
 
Hi, christian, As I understood, your trouble, is to define the pressure value, at the defined location and defined time. I think you should write a sub-routin, for your problem and link it to fluent through, UDF. I think your problem should be calculated az a source term in the momentum equations.

Erwin February 16, 2003 18:11

Re: Unsteady state case setup
 
If the pressure increase is instantaneous you could use the Patch function (under Initialize menu) to give a specific fluid zone (or adaption register if you don't have this predefined fluid zone) a new value for the pressure at specific time t. If the pressure increase is more gradual then you'll have to resort to a UDF.


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