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data sets; Heat Transfer

Posted 2 juil. 2014, 04:04 UTC−4 Heat Transfer & Phase Change, Results & Visualization Version 4.4 3 Replies

David Fernandez Bosman
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Hi COMSOL user's

I'm trying to model the heat transfer in a set of detectors connected to some electronics components that consume Watts. My geometry in three dimensions is complicated and it requires a big computational cost, so what I'm doing is to model it in two dimensions. I can do this because there is symmetry with respect both to the geometry and the potency consumed.

I'm comparing the results in two and three dimensions in simple cases, in order to make sure I'm doing well. I'm doing this by exporting the data in a txt file and then plotting them with root. I would like to do this with COMSOL. What I did is to have two components in my COMSOL project, one for the two dimensions case and the other for the three dimension case. Then I used the same time-dependent solver for solving the two (I Think), but then I'm not able two plot, for instance, the time vs. temperature in a two points (one in the 3D geometry and the other in the 2D geometry).

I think the question would be:

It is possible to plot in the same canvas data coming from different components?

Thank you,

David
3 Replies Last Post 3 juil. 2014, 10:56 UTC−4
Pieter Westerik
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Posted: 1 decade ago 3 juil. 2014, 03:49 UTC−4
In the results node there is a node 'data sets'. If you right click it you can add a 'cut plane' in which you can evaluate your 3D data in a 2D plane. I think then you could plot the solution of your 2D model and the data from the cut plane in the same 2D graph.
In the results node there is a node 'data sets'. If you right click it you can add a 'cut plane' in which you can evaluate your 3D data in a 2D plane. I think then you could plot the solution of your 2D model and the data from the cut plane in the same 2D graph.
David Fernandez Bosman
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Posted: 1 decade ago 3 juil. 2014, 09:43 UTC−4
Hi Pieter,

Thanks for your answer. I finally managed to plot the two functions in the same graph.

In the "data sets" node two "solution" sub-nodes are displayed, one for the solutions of the 3D case and the other for the 2D case. One way to plot the temperature vs. time on a point is to define this point in the "data sets" node. In the settings of this point, you are asked to give the solution i.e. the component (geometry) where you want to draw the point, so that if I choose the solution corresponding to 3D I will be asked to give the x, y and z coordinate, while if I choose the solution corresponding to 2D I will be asked to give the x and y coordinate. So you can define 2 points, one for the 3D and the other for the 3D
When you crate the "1D plot group" node, you are again asked to give the "solution" and also your have the option "none". The only way to plot using the points predefined is to choose in the "1D plot group" settings the solution you want and then in the sub-node "point graph" settings choose the point corresponding to this solution. But doing this you will never be able to plot two functions coming from different "data sets" solutions.

There is another way. If you choose the option "none" in the "1D plot group" settings and you create two "point graphs" sub-nodes, you can select in each of this sub-nodes settings your solution, instead of choosing the predefined point. If you do this, you cannot use the predefined points, but in the selection settings you can choose the points, that you have to have predefined in the "definitions" node.
It is complicated to explain with words. I hope it is understandable

Cheers!

David
Hi Pieter, Thanks for your answer. I finally managed to plot the two functions in the same graph. In the "data sets" node two "solution" sub-nodes are displayed, one for the solutions of the 3D case and the other for the 2D case. One way to plot the temperature vs. time on a point is to define this point in the "data sets" node. In the settings of this point, you are asked to give the solution i.e. the component (geometry) where you want to draw the point, so that if I choose the solution corresponding to 3D I will be asked to give the x, y and z coordinate, while if I choose the solution corresponding to 2D I will be asked to give the x and y coordinate. So you can define 2 points, one for the 3D and the other for the 3D When you crate the "1D plot group" node, you are again asked to give the "solution" and also your have the option "none". The only way to plot using the points predefined is to choose in the "1D plot group" settings the solution you want and then in the sub-node "point graph" settings choose the point corresponding to this solution. But doing this you will never be able to plot two functions coming from different "data sets" solutions. There is another way. If you choose the option "none" in the "1D plot group" settings and you create two "point graphs" sub-nodes, you can select in each of this sub-nodes settings your solution, instead of choosing the predefined point. If you do this, you cannot use the predefined points, but in the selection settings you can choose the points, that you have to have predefined in the "definitions" node. It is complicated to explain with words. I hope it is understandable Cheers! David
Pieter Westerik
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Posted: 1 decade ago 3 juil. 2014, 10:56 UTC−4
Yes indeed to use two different solutions in one graph you have to add two different graph nodes to one plot group node.
Yes indeed to use two different solutions in one graph you have to add two different graph nodes to one plot group node.

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