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Inlet Boundary condition changing during the simulation

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I would like to change inlet boundary condition during the simulation. I would to impose on this boundary:

1. A Temperature condition during the charging time (0 – 25000 s)
2. Heat flux boundary condition during the dormancy stage (25000 s – 500000s )

Is it possible? How to do it?

2 Replies Last Post 7 juin 2012, 09:44 UTC−4

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Posted: 1 decade ago 7 juin 2012, 08:37 UTC−4
Hi Siyad,

As far as I know it is not possible the change the type of boundary condition during a simulation. However there are some workarounds for this problem.

You could solve your problem with the temperature boundary for until t=25000s, store the solution, manually change the boundary condition to a heat flux one, and use the stored solution as an initial condition for the second stage. When you only need to do a few simulations this might be a solution.

When you need to do a lot of simulation you could try and implement this in MATLAB, using the functionality that lets you run Comsol models in MATLAB.

The last solution I can think of is dependent on the kind of problem you are trying to solve. Maybe there is a way emulate a heat flux condition with the use of a temperature condition with the use of specific functions. Or the other way around (emulate temperature cond. as a heat flux one). Then again this really depends on your physics, so you might want to post the model?
Hi Siyad, As far as I know it is not possible the change the type of boundary condition during a simulation. However there are some workarounds for this problem. You could solve your problem with the temperature boundary for until t=25000s, store the solution, manually change the boundary condition to a heat flux one, and use the stored solution as an initial condition for the second stage. When you only need to do a few simulations this might be a solution. When you need to do a lot of simulation you could try and implement this in MATLAB, using the functionality that lets you run Comsol models in MATLAB. The last solution I can think of is dependent on the kind of problem you are trying to solve. Maybe there is a way emulate a heat flux condition with the use of a temperature condition with the use of specific functions. Or the other way around (emulate temperature cond. as a heat flux one). Then again this really depends on your physics, so you might want to post the model?

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 7 juin 2012, 09:44 UTC−4
Hi

these changed of BC conditionally linked to the solver studies will be possible in V4.3 somewhere in the post these days

--
Good luck
Ivar
Hi these changed of BC conditionally linked to the solver studies will be possible in V4.3 somewhere in the post these days -- Good luck Ivar

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