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optimization of a time-dependent problem

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Hi everybody, can you indicate me a Comsol doc or a Comsol tutorial paper in which i can find an approach to solve time-dependent optimization problems? The fact is that I need to know if it is possible to solve with Comsol an inverse heat transfer problem with the aim of finding the unsteady heat flux boundary conditions employing experimental temperature values. And I think that probably it could be done with the Comsol optimization module.
Thanks in advance

Luigi

12 Replies Last Post 10.09.2015, 13:47 GMT-4
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Hello Luigi Mongibello

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Posted: 1 decade ago 25.03.2011, 08:34 GMT-4
Did you find the answer of your question? I have the same question as well. Please let me know if you acheived any information about optimization in a time dependent module.
Thanks
Atieh
Did you find the answer of your question? I have the same question as well. Please let me know if you acheived any information about optimization in a time dependent module. Thanks Atieh

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Posted: 1 decade ago 05.05.2011, 06:40 GMT-4
I have the same difficulty!
I have the same difficulty!

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Posted: 1 decade ago 05.05.2011, 07:37 GMT-4
yes. In time dependent cases I use comsol with matlab and write the inverse problem solver in matlab.
ciao
yes. In time dependent cases I use comsol with matlab and write the inverse problem solver in matlab. ciao

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

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Posted: 1 decade ago 05.05.2011, 09:21 GMT-4
Hi

it can be done inside COMSOL too , there were a few eamples in 3.5, they must have been ported to v4, have a look

--
Good luck
Ivar
Hi it can be done inside COMSOL too , there were a few eamples in 3.5, they must have been ported to v4, have a look -- Good luck Ivar

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Posted: 1 decade ago 05.05.2011, 09:30 GMT-4
The same question. I want to do transient electromagnetic and heat transfer study in Comsol. There is one sample on microwave heating. I tried to follow that example to build my own, however it doesn't work. I can only get the stationary electric field result but there is no result on heat transfer.

Did any one have the same experience? How did you solve it?
thanks
The same question. I want to do transient electromagnetic and heat transfer study in Comsol. There is one sample on microwave heating. I tried to follow that example to build my own, however it doesn't work. I can only get the stationary electric field result but there is no result on heat transfer. Did any one have the same experience? How did you solve it? thanks

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

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Posted: 1 decade ago 05.05.2011, 10:02 GMT-4
Hi

I can suggest to ask yourself: how did you define the head source in the HT module as coming from the EM module ?

--
Good luck
Ivar
Hi I can suggest to ask yourself: how did you define the head source in the HT module as coming from the EM module ? -- Good luck Ivar

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Posted: 1 decade ago 28.06.2011, 05:43 GMT-4
Hello,

I have similar kind of problem. My problem is:

The problem is time dependent. I am working using chemical engineering module. I have used a set of parameters. In my model, I am computing concentrations of different species in different domains. For the comparison purpose, I use the available experimental data. Given a certain range for the parameters, I want to compute the optimized parameters such that I get the best fit (at certain values of time) compared with the experimental data.

I have no idea how can I do it comsol or use matlab in it. So, I have to start from scratch. Can any one please guide me or share your model, so that using the same idea, I may implement it in my problem.

I will be really thankful to you.

Best Regards

Qasim
Hello, I have similar kind of problem. My problem is: The problem is time dependent. I am working using chemical engineering module. I have used a set of parameters. In my model, I am computing concentrations of different species in different domains. For the comparison purpose, I use the available experimental data. Given a certain range for the parameters, I want to compute the optimized parameters such that I get the best fit (at certain values of time) compared with the experimental data. I have no idea how can I do it comsol or use matlab in it. So, I have to start from scratch. Can any one please guide me or share your model, so that using the same idea, I may implement it in my problem. I will be really thankful to you. Best Regards Qasim

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Posted: 1 decade ago 28.06.2011, 06:52 GMT-4
Hi, I think you should convert your comsol case into a matlab .m file, and implement an iterative method at each time step, for ex. conjugate gradent method, to fit the time-dependent experimental data. This procedure is quite simple if experimental data can be represented by an analytic function of time. Actually I don't know any solution to solve your problem within comsol environment.
Best regards

Luigi
Hi, I think you should convert your comsol case into a matlab .m file, and implement an iterative method at each time step, for ex. conjugate gradent method, to fit the time-dependent experimental data. This procedure is quite simple if experimental data can be represented by an analytic function of time. Actually I don't know any solution to solve your problem within comsol environment. Best regards Luigi

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Posted: 1 decade ago 28.06.2011, 08:22 GMT-4

Hi, I think you should convert your comsol case into a matlab .m file, and implement an iterative method at each time step, for ex. conjugate gradent method, to fit the time-dependent experimental data. This procedure is quite simple if experimental data can be represented by an analytic function of time. Actually I don't know any solution to solve your problem within comsol environment.
Best regards

Luigi


Dear Luigi,

I am very thankful to you for your reply. I have created a very simple model in comsol 3.5a. Then saved as m file. Can you please help me, how to add optimization function in this m file. My task is to minimize the error between the experimental data and the modeling data obtained from the Integration function (I1=postint). I am attaching the model file, m file and data file. I will be extremely grateful to you for this kindness.

Thanks
[QUOTE] Hi, I think you should convert your comsol case into a matlab .m file, and implement an iterative method at each time step, for ex. conjugate gradent method, to fit the time-dependent experimental data. This procedure is quite simple if experimental data can be represented by an analytic function of time. Actually I don't know any solution to solve your problem within comsol environment. Best regards Luigi [/QUOTE] Dear Luigi, I am very thankful to you for your reply. I have created a very simple model in comsol 3.5a. Then saved as m file. Can you please help me, how to add optimization function in this m file. My task is to minimize the error between the experimental data and the modeling data obtained from the Integration function (I1=postint). I am attaching the model file, m file and data file. I will be extremely grateful to you for this kindness. Thanks

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Posted: 1 decade ago 29.06.2011, 10:18 GMT-4
I'm sorry but it would take too much time for me. Anyway, I am sure you can do it by yourself.
Regards
I'm sorry but it would take too much time for me. Anyway, I am sure you can do it by yourself. Regards

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Posted: 1 decade ago 29.06.2011, 10:37 GMT-4

I'm sorry but it would take too much time for me. Anyway, I am sure you can do it by yourself.
Regards


Hello,

I understand but If you could give me some hints or refer me to any example, it will be really helpful. Any way thanks for your reply.

Best Regards

Qasim
[QUOTE] I'm sorry but it would take too much time for me. Anyway, I am sure you can do it by yourself. Regards [/QUOTE] Hello, I understand but If you could give me some hints or refer me to any example, it will be really helpful. Any way thanks for your reply. Best Regards Qasim

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Posted: 9 years ago 10.09.2015, 13:47 GMT-4
Did anyone get the answer? How to optimize a heat flux boundary within COMSOL environment?
Did anyone get the answer? How to optimize a heat flux boundary within COMSOL environment?

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