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How to use COMSOL to solve problems with dimensionless time and distance but not conventional t and x???

Posted 26 janv. 2015, 03:59 UTC−5 Version 4.4 6 Replies

Shirley Long
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In my model, I need to transfer the conventional mathematical model into dimensionless one. For example, transfer t into ι=t*u/n/L . Then I have to draw picture with dimensionless distance and time. How can I achieve that ???

The picture like one of the the COMSOL conference paper by Ben Niu?????
Thank you?

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6 Replies Last Post 27 janv. 2015, 02:55 UTC−5
Lasse Murtomäki
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Posted: 10 years ago 26 janv. 2015, 07:10 UTC−5
You can define any variable or their combination in the plot definitions.

In the main window of Comsol model you can select the unit system; there is also a dimensionless option.

Lasse
You can define any variable or their combination in the plot definitions. In the main window of Comsol model you can select the unit system; there is also a dimensionless option. Lasse
Shirley Long
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Posted: 10 years ago 26 janv. 2015, 07:13 UTC−5
Hello Lasse:
Thank you very much for your technical help. I'll try it.

Shirley
Hello Lasse: Thank you very much for your technical help. I'll try it. Shirley
Shirley Long
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Posted: 10 years ago 26 janv. 2015, 07:24 UTC−5
Hello Lasse，

I have modified the model with the method you told me, but there is still some problems.

I want to repeat the model in this paper and make some improvements, draw the relations between c and dimensionless time.

Can you tell me how to achieve that??? Thank you very much.

Shirley
Hello Lasse， I have modified the model with the method you told me, but there is still some problems. I want to repeat the model in this paper and make some improvements, draw the relations between c and dimensionless time. Can you tell me how to achieve that??? Thank you very much. Shirley

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Lasse Murtomäki
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Posted: 10 years ago 26 janv. 2015, 09:45 UTC−5
What's the problem? Reading the paper takes some effort...

Lasse
What's the problem? Reading the paper takes some effort... Lasse
Shirley Long
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Posted: 10 years ago 26 janv. 2015, 20:17 UTC−5
Get a relationship curve between concentration C and dimensionless time . But in the model the default is conventional time t, even I set the unit system to be non in the main surface.
Get a relationship curve between concentration C and dimensionless time . But in the model the default is conventional time t, even I set the unit system to be non in the main surface.
Lasse Murtomäki
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Posted: 10 years ago 27 janv. 2015, 02:55 UTC−5
You need to make a global plot:

Results --> 1D Plot Group --> Global --> x Axis Data --> Parameter: Expression

There you can put your dimensionless time.

Wish this helps
Lasse

You need to make a global plot: Results --> 1D Plot Group --> Global --> x Axis Data --> Parameter: Expression There you can put your dimensionless time. Wish this helps Lasse

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