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transient boundary condition

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Hi,

I would like to set-up a boundary condition in the convection-diffusion mode that initially begins as a source but after a certain period is switched off to become a normal insulated (or convective flux) boundary. I tried finding the solution in two parts, using the solution for the first part as an initial condition for the second but it didnt seem to work so well. Presumably there is something more obvious that I am missing?

Thanks,
Adam

2 Replies Last Post Sep 24, 2009, 10:56 a.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Sep 24, 2009, 10:40 a.m. EDT
Hi

this has been discussed a couple of times earlier I believe, at lieast similar demands, try an "advanced search" on "boundary conditions" "GO", just below the "DISCUSSION FORUM" banner.

to "simply" turn on and off a value you can set a conditional "*(t<0.5)" on your value (if you are in time domain, or *(Param<3) if you are running a parametric sweep with "Param" as parameter.

but on AC/DC BC's you want often to switch other things too, then you could must look at the true setting of your BC's at eqaution level and play with them.

Other suggestions in the previous discussions

Good luck
Ivar
Hi this has been discussed a couple of times earlier I believe, at lieast similar demands, try an "advanced search" on "boundary conditions" "GO", just below the "DISCUSSION FORUM" banner. to "simply" turn on and off a value you can set a conditional "*(t

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Posted: 1 decade ago Sep 24, 2009, 10:56 a.m. EDT
Thank you Ivar, I was perhaps a bit hasty in posting this as I found some good suggestions in other threads as you mentioned.
Thank you Ivar, I was perhaps a bit hasty in posting this as I found some good suggestions in other threads as you mentioned.

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