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-   -   Time changing boundary condition (http://www.cfd-online.com/Forums/cfx/91843-time-changing-boundary-condition.html)

jasper558 August 24, 2011 09:09

Time changing boundary condition
 
Hello guys

I have to run a transient simulation in which one of the boundary is radiation source and the radiation intensity id time dependent, its something like this..

Time
from to radiation
09:00 10:00 40 Wm-2
10:00 11:00 180 Wm-2
11:00 12:00 350Wm-2
12:00 13:00 340 Wm-2
13:00 14:00 370 Wm-2
14:00 15:00 290 Wm-2
15:00 16:00 400 Wm-2
16:00 17:00 390 Wm-2
17:00 18:00 250 Wm-2
18:00 19:00 70 Wm-2

i created a function "Rad" with argument as time (mins) and value as radiation... somewhat like:
2 40
62 180
122 350 and so on....
and then a expression called "Radiation" with value "Rad(Time Step)" the transient simulation has to runs for 10 hr time period with 4 min time step.
im not sure if i have done it correctly..... can anyone tell me is it correct, nad if not then please advise

ghorrocks August 24, 2011 18:43

Sounds OK. Or you can skip the Radiation expression bit and make the radiation condition at the boundary simply defined as rad(t).

Not sure about your definition of Rad(Tiem Step) - shouldn't this be Rad(t), that is of time?


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