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-   -   How to change the boundary condition at a certain time? (https://www.cfd-online.com/Forums/fluent/130180-how-change-boundary-condition-certain-time.html)

masoud90 February 21, 2014 00:18

How to change the boundary condition at a certain time?
 
Hi everyone,
I want to simulate the air motion with ANSYS FLUENT in a cylinder which has 2 valves. The inlet valve has to be closed at a certain time let's say t0 and the outlet has to be opened at this time.
How can I change the boundary condition of inlet from inlet to wall and the boundary condition of outlet from wall to outlet at the time t0?
Hope someone can help me out. Thanks.

Kina February 21, 2014 16:44

what you probably want is a UDF for your transient analysis. There is a tutorial for using UDFs for fluent that you might wanna consider. Also, http://aerojet.engr.ucdavis.edu/flue...df/node231.htm might be useful for you. pay attention to parallelizing the udf when running fluent parallel.

masoud90 February 21, 2014 17:33

Thank you Kina,
Actually my problem is the outlet ! I don't want to have a outlet until the time t0,I mean the fluid before time t0 only has inlet valve. after t0 I want to have outlet in different place from the inlet....do you have any suggestion ?
Thanks

Kina February 22, 2014 10:53

There has been a thread with code for such an action. As I don't understand much of scheme programming, I can only guess what most of the code does but maybe you should give it a try.
http://www.cfd-online.com/Forums/flu...tion-type.html
I'll have a look at it when I have more time next week but with the code in the other topic you should be able to figure most of it out.

masoud90 February 23, 2014 13:56

Thank you for the link. it is helpful.


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