Cel expressions Time dependent
Hi everybody,
I want to create a variable through a CEL Expression dependent of the value of this variable at the former timestep. How can I make it? thanks in advance 
Re: Cel expressions Time dependent
Hi You've fixed or variable timestep

Re: Cel expressions Time dependent
I have fixed timestep

Re: Cel expressions Time dependent
It's seem to be simple but I don't know what do you want to do with this variable. Can u explain more thx

Re: Cel expressions Time dependent
I have the same problem. I wanna put a heat flux, in [W/m^2] as a boundary condition (BC) that varying with the time "t", in [s], using the CEL expressions. At the CFX v5.6, the BC of heat flux must have the same unity, as [W/m^2].
If my heat flux varies with the time as, for example: q(t)=t^2+3*t4 with q in [W/m^2] and t (time, not T of temperature) in [s]. My doubt: How to transform the expression 't^2+3*t4' from [s] to [W/m^2]? I can´t use a heat flux as a BC in [s]. Only in [W/m^2]. Rogerio. 
Re: Cel expressions Time dependent
Hello Rogerio to do these operation you've to use fortran subroutine best regards

Re: Cel expressions Time dependent
How?

Re: Cel expressions Time dependent
Rogerio, I think you may try to divide t by the unit (1 [s]) and turn it into an adimensional expression. Then you multiply the result by the new unit.
Your expression then becomes q(t)=((t/1 [s])^2+3*(t/1 [s])4)*1 [W/m^2] Hope it helped. 
Re: Cel expressions Time dependent
This way, I think it´s better (on CFXv5.6 version):
Expression Editor Expressions Name Definition AA 1.0 s BB 1.0 W m^2 HeatFlu BB*(t/AA)^2+3*(t/AA)^4 Please, see page 123 from CFX5 Tutorials. I´d like to thank for helping me. Rogério Fernandes Brito. 
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