Hello,

I am following up on the questions I have already asked you here : How to create time varying material property ?

I need more clarification if possible.

I am working on a project where we study the propagation of an electromagnetic wave in a medium where the dielectric permittivity and the magnetic permeability vary according to time and space.

The problem consists of a rectangle where there is a sinusoidal electric field excitation on the left edge, PMC conditions on the top and bottom edges and an absorbing condition on the right edge (cf. image). The wave crosses 3 media with the following properties :

- ε0, μ0
- ε = ε(x,t) = ε0*(εr0+δε
*cos(ωt-kx)), μ = μ(x,t) = μ0*(μr0+δμ*cos(ωt-kx)) - ε0, μ0

I wish to adapt the variational formulation for this problem but I have some difficulties. Here is my weak formulation :

My questions are therefore:

- Is it enough to take into account the electric excitation on the left edge as a constraint? Or should we add a term in the variational formulation?
- I don't see the possibility of writing the Laplacian operator, is there one? If not, do I have to go through a Green formula?
- How to write the temporal derivatives? I understand that "DtDof" only applies to the unknown in "Dof" and we cannot use "Dt".
- I have defined permittivity and permeability in "Function" as follows:
`epsilon [Domain 1] = eps0;`

`epsilon [Domain 2] = eps0 * (epsr0 + d_eps*Cos[w*$Time-k*X[]];`

`epsilon [Domain 3] = eps0;`

Is this the right way to go? I used X[] instead of $X because $X didn't seem to work. - Should we work in BF_Node or in BF_PerpendicularEdge?

Best regards,

KOENIG Jules

Great, thank you very much for this information! I have what I need, Silver Muller's condition should be enough.

Koenig Jules

Hello,

I built a simple model consisting of two rectangular surfaces with different permittivities. I have placed a sinusoidal source point in the upper rectangle.

I then do a temporal study of the propagation of the wave between the two media. However I find myself with unwanted reflections on the boundaries of the domain. I therefore wish to implement absorbing boundaries of ABC or PML type.

I could see that these are implemented in the "AcousticScattering" project. However they are in the frequency domain and moreover the associated code is very bulky and I admit having great difficulty in adapting it to my study.

Could you tell me how to implement as simply as possible one of these two absorption conditions?

I have attached the source files and some screenshots of the model.

I thank you in advance,

KOENIG Jules

Hello,

I am working on OneLab - Gmsh - GetDP.

I want to model a material whose relative permittivity varies over time. Do you know if this is possible ?

I know that we can make a constraint which varies in time, but in order to modify the permittivity of the material over the time, it would be necessary rather that the temporal variation is taken into account in the variational formulation.

Thank you in advance,

KOENIG Jules

Sorry, I've completely forget to answer. Thank you very much for responding quickly.

I tried with C++, but it didn't work (for some other reason). I will get back to you if I can resolve this particular issue.

But we also realized (as Till Piepenbrock specifies), that with macOS and even Linux, it works very well.

There is therefore a firewall problem on Windows or something else that we didn't resolved. So we decided to work on Linux.

If anyone ever finds a solution to overcome the windows problem, I'm a taker. Thank you again for your responsiveness.

Jules KOENIG

Hello,

With several students we are working on OneLab. We encounter a problem to open any python file on gmsh: "Abnormal server termination (Socket listening timeout on socket 127.0.0.1:0)"

We were careful to copy the Onelab.py file to the folder where the working python file is located (for example that of the pendulum). We have also tried to disable the firewall and antivirus. But nothing works.

I saw that this problem was mentioned on several forums, but I did not see a solution.

Do you have an idea ?

Thank you in advance.

Koenig Jules

Hello, With several students we are working on OneLab. We encounter the same problem to open any python file on gmsh: "Abnormal server termination (Socket listening timeout on socket 127.0.0.1:0)".

We were careful to copy the Onelab.py file to the folder where the working python file is located (for example, the pendulum one). We have also tried to disable the firewall and antivirus. But nothing works.

I saw that this problem was mentioned on several forums, but I did not see a solution.

Do you have an idea ?

Thank you in advance.

Koenig Jules