# time dependent B.C

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 November 11, 2003, 12:25 time dependent B.C #1 co2 Guest   Posts: n/a Dear Fluent users, Please help me out with the following question - In my model, I have a wall with heat flux B.C. Now I need to change the heat flux value every minute - thus making it a time varying B.C. But I have no idea as to how to do it - I know it has something to do with profile writing etc. But I have not found a fluent tutorial that can tell me how to do it - The help files discuss this topic but I have not been able to really do anything with it. Can someone provide me some example of the profile file, a tutorial etc, may be some other website.. Thank you and looking forward to a helpful reply from someone.

 November 18, 2003, 20:59 Re: time dependent B.C #2 Alamgir Guest   Posts: n/a it should be like velocity profile UDF. only u need to replace velocity with heat flux, (before proceding just get information what fluent macro is for heat flux). then call udf whr u put the value of heat flux. if it is not enough just write to me, I may help u in this regard. Alamgir

 November 18, 2003, 21:01 Re: time dependent B.C #3 Alamgir Guest   Posts: n/a It should be like usteady velocity profile UDF

 November 26, 2003, 15:55 Re: time dependent B.C #4 co2 Guest   Posts: n/a Alamgir, thanks for your note. i was able to change the temperature of the wall using a function definition just the way they had shown in manual for transient velocity. but how to do the same with heat flux. I actually have a formula for calculation of this heat flux and it depends on the revolution of sun around the object. the formula also requires some other complicated angles etc. let us say i do these calculations seperately in a excel spreadsheet and get the heat flux values for each minute of different walls. how do i feed these calculated values to the udf for heat flux of a particular wall?