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"Expression" under "Datasets -> a certain dataset" functions or not?

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I found that, for the part of "Expression" under "Datasets -> a certain dataset", it's no use to have this part, since no matter plot or export the data, you need to enter the expression again.

Even you plot this dataset, it shows (my guess) just the FEM nodes' distribution, right?

Then my Qs are 1. Does this part do function? What's its function? 2. Plotting the dataset plots simply the FEM distribution, right?



2 Replies Last Post Apr 2, 2024, 1:35 p.m. EDT
Gunnar Andersson COMSOL Employee

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Posted: 7 months ago Apr 2, 2024, 12:03 p.m. EDT
Updated: 7 months ago Apr 2, 2024, 12:03 p.m. EDT

The Isosurface and Contour datasets would typically be used when you use one expression in the dataset and another expression in the features that uses the dataset. An example: Suppose that you want to compute the area of the isosurface c=0. Then you can use an Isosurface dataset where you specify c=0 and a Surface Integration feature that refers to the Isosurface dataset and uses the expression 1. You can also use a Surface Measurement feature to compute the area.

The **Isosurface** and **Contour** datasets would typically be used when you use one expression in the dataset and another expression in the features that uses the dataset. An example: Suppose that you want to compute the area of the isosurface c=0. Then you can use an **Isosurface** dataset where you specify c=0 and a **Surface Integration** feature that refers to the **Isosurface** dataset and uses the expression 1. You can also use a **Surface Measurement** feature to compute the area.

Jeff Hiller COMSOL Employee

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Posted: 7 months ago Apr 2, 2024, 1:35 p.m. EDT
Updated: 7 months ago Apr 3, 2024, 2:54 a.m. EDT

To illustrate Gunnar's point, the attached file shows how you can use an Isosurface dataset to create a plot of the magnitude of the heat flux on the complicated surface defined by the fact that the temperature equals 300 kelvin on it.

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Jeff Hiller
To illustrate Gunnar's point, the attached file shows how you can use an Isosurface dataset to create a plot of the magnitude of the heat flux on the complicated surface defined by the fact that the temperature equals 300 kelvin on it.

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