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## Box simulation domain with circular dielectric disc inside

Posted 2018年5月9日 GMT-0400上午11:18 4 Replies

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Hi all,

I am using the equation based modeling to solve a coefficient form pde.

I want to have a simulation domain with a box shape and inside the box I want to place a cylinder with radius r and height h. The cylinder has dielectric constant epsilonr=3. All other space is Air.

Under the point geometry I now added a Box and also I add the cylinder inside the box domain.

I think I now have to define the disjoint domain of the cylinder with the Box. This domain I will call D in the following.

In the following I have to give the domain D the dielectric constant epsilonr=1 and the cylinder epsilonr=3.

Is this strategy correct?

To get the domain D I did

right click on Geometry > Booleans and Partitions > Difference

And then I select the two domains which I want to subtract.

My question is: How do I tell COMSOL that the two different domains have different epsilonr? I have created two materials, one with epsilonr=1 and the other one with epsilonr=3. But how do I assign the two domains (D and Cylinder ) to these two meterials?

In the end I will write the constant epsilonr into the pde.

Many thanks in advance.