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May 31, 2012 6:04am UTC

Initial values from a PDE

Hallo Comsol - expert,

I am trying to setup a transient simulation where the initial values of the dofs are
calculated in a dedicated physics node. All is in a 2-D plane.

The transient simulation is a PDE General Form ("g") with Hx, Hy as unknowns (think of
magnetic field strengths). I am interested in the transient behaviour starting from
a particular crafted initial state.

For the initial state I want to solve a stationary magnetis simulation ("mf", unknown Az).
From the solution I can derive the magnetic field strength (mf.Hx and mf.Hy) which are
the desired initial values for "g".

How can I transfer the output data of one physics section as initial values to anoteher
physics section?

I tried:
1. Study1 only solves "mf"
2. Study2 only solves in "g"
3. Study2 in the section "Values of variables that you do not solve for" I refer to Study1
(Method ="Solution" and Study="Study"
4. In "g" I use mf.Hx and mf.Hy as initial values.

BUT the initial values are all zero.

Does anyone have an idea to fix my approach or different ideas?
I could live with saving data to a file and reloading it.

Thanks for any hints.

Jens

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May 31, 2012 6:29am UTC in response to Ivar Kjelberg

Re: Initial values from a PDE

Hi Ivar,

I did that already and tried all possible settings and all remains zero. The help
refers to using solutions from different study steps but for the same physics.

What I need is cross initialisation.


Jens

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May 31, 2012 7:23am UTC in response to Ivar Kjelberg

Re: Initial values from a PDE

Hi Ivar,

well I used "mf.Hx" in the initial tab. Is that what you mean with "variables"?

I attach a simplified model, which just does initialsation in the transient study.

Thanks

Jens

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June 4, 2012 7:35am UTC in response to Ivar Kjelberg

Re: Initial values from a PDE

Hi,

I tried both and also when the stationary is in the same study the link is
not done.

On the PDE node I do not change the settings after creating
the node (except for the initial conditions).

I'm asking support,

Thanks,

Jens

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June 4, 2012 9:27am UTC in response to Ivar Kjelberg

Re: Initial values from a PDE

Hi,

interessting that it works for you. I tried someting very simple

Hx=x
Hy=y

and these initial conditions are considered correctly. But the
values from the other physics not.

What are your setting in "Values of variables that you do not solve for"?
Is there something users usually do wrong?


Jens

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