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Defining initial condition

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Hi,

My geomtry is consisted of 2 boxes.

And, I am trying to define inital condition of one box by previous solution,

the other box by defining from initial values node.

But I found that the initial value of whole geomtry is defined by the previous solution.

Please help.

Thanks.

1 Reply Last Post 21 mars 2012, 02:45 UTC−4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 21 mars 2012, 02:45 UTC−4
Hi

indeed that is what I understand as the "default" behaviour. What you have not explained, is if you have 2 studies on the same pysics or 2 physics each with a separate physics.

I believe you need to define a model physics dependent variable, that is then solved by solution 1, and then in pyhsics 2 you define the initial condition with this variable

The only other trick I know about is if you mix a stationary and a time dependent series, then the variable "t" can be used a s "switch" for BC's, i.e. you define t=0 or t=-1[s] as a global parameter, solve the stationary solution by using boolean tests of the type (t<0) or t==0) and t>0) to switch the BC values at will, then when you launch the time setudy, COMSOl will overwrite the t value and make it grow, hence switch your BC to the time dependent case.

You can add another switch by using the stationary continuation sweep feature with a fixed parameer Param that you use too, see the example (it's 4.2a)

--
Good luck
Ivar
Hi indeed that is what I understand as the "default" behaviour. What you have not explained, is if you have 2 studies on the same pysics or 2 physics each with a separate physics. I believe you need to define a model physics dependent variable, that is then solved by solution 1, and then in pyhsics 2 you define the initial condition with this variable The only other trick I know about is if you mix a stationary and a time dependent series, then the variable "t" can be used a s "switch" for BC's, i.e. you define t=0 or t=-1[s] as a global parameter, solve the stationary solution by using boolean tests of the type (t0) to switch the BC values at will, then when you launch the time setudy, COMSOl will overwrite the t value and make it grow, hence switch your BC to the time dependent case. You can add another switch by using the stationary continuation sweep feature with a fixed parameer Param that you use too, see the example (it's 4.2a) -- Good luck Ivar

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