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Using results from one simulation run as initial conditions for next simulation run

Posted Oct 24, 2011, 2:45 p.m. EDT Fluid & Heat, Results & Visualization, Studies & Solvers Version 4.2 3 Replies

Radhika Ramachandran
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Hi,

I am trying to create a model (one component diffusing into the surrounding component) which involves diffusion at 2 temperatures (4C and 30C). The diffusing agent diffuses a certain distance at 4C and then the temperature changes to 30C. The diffusivity values at these 2 temperatures are also different.

I want to use the results from the diffusion at 4C as the initial conditions for the diffusion at 30C. Is there any way I can do the same?
Any help/advice would be greatly appreciated.

Thanks in advance!!

Radhika

3 Replies Last Post Oct 27, 2011, 9:52 a.m. EDT
Shriram Reguraman
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Posted: 1 decade ago Oct 25, 2011, 1:00 p.m. EDT
Yes, You can do so if you use 2 different solvers.

In the second solver, under dependent variables, look at initial values (2nd heading).

There, you can select method as solution and solution as the previous solver, and also if its time dependent you can select the specific time as the initial condition.

Shriram
Yes, You can do so if you use 2 different solvers. In the second solver, under dependent variables, look at initial values (2nd heading). There, you can select method as solution and solution as the previous solver, and also if its time dependent you can select the specific time as the initial condition. Shriram
Shoval Zoran
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Posted: 1 decade ago Oct 27, 2011, 8:54 a.m. EDT
Do you mean using two studies, and after the first one solves, using the other study with initial conditions from the first one, or having two solvers inside one study and then referring from one to another? I don't have a use for it now but I expect to have one in the future.

Thank you in advance,
Shoval
Do you mean using two studies, and after the first one solves, using the other study with initial conditions from the first one, or having two solvers inside one study and then referring from one to another? I don't have a use for it now but I expect to have one in the future. Thank you in advance, Shoval
Gadi Oron
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Posted: 1 decade ago Oct 27, 2011, 9:52 a.m. EDT
I am facing a similar problem and found another possibility

- define the parameter that is changed as a piecewise function of time (in definitions)
- to fix the right unit - define a variable that is equal to the function you defined times the unit
- use this variable wherever it is required

The only downside of this method is that you will need to take care of convergence at the step function - generally add some transition to it or decrease the timestep.

If you succeed in using the other proposed technique, I would be glad to get a sample model of it.

Ciao
I am facing a similar problem and found another possibility - define the parameter that is changed as a piecewise function of time (in definitions) - to fix the right unit - define a variable that is equal to the function you defined times the unit - use this variable wherever it is required The only downside of this method is that you will need to take care of convergence at the step function - generally add some transition to it or decrease the timestep. If you succeed in using the other proposed technique, I would be glad to get a sample model of it. Ciao

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