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Electric Field dependant Equation entry in COMSOL 5.2

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If I want to express that the conductivity of the material depends on the Electric Field in Y direction (Ey). How should I write Ey in the equation in this case.

I want to know how I can make realize the variable Ey in COMSOL.

9 Replies Last Post 11.07.2016, 10:30 GMT-4

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Posted: 8 years ago 07.07.2016, 18:48 GMT-4
You can find variable names after enabling Equation View. But there are several related to Ey, and I'm not sure which one is which one...

--
Pu, ZHANG
DTU Fotonik
You can find variable names after enabling Equation View. But there are several related to Ey, and I'm not sure which one is which one... -- Pu, ZHANG DTU Fotonik

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Posted: 8 years ago 07.07.2016, 23:06 GMT-4
Thanks Zhang ! Let me see what can i get from it.

-RA
Thanks Zhang ! Let me see what can i get from it. -RA

Jeff Hiller COMSOL Employee

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Posted: 8 years ago 08.07.2016, 08:41 GMT-4
Hello Rishad and Pu,

Besides using the Equation View button, another approach consists in using the postprocessing tools, see for instance www.comsol.com/community/forums/general/thread/114702 .

Another neat approach is now available in version 5.2a. We've added (or, to be more accurate I should say, we've greatly expanded) autocomplete. So, let's say you want to set the conductivity to "1+the y component of the electric field computed by the ec physics interface" but you don't know the syntax for the y component of the electric field computed by the ec physics interface. In the text field where you specify the conductivity, you can start typing "1+ec." then go Ctrl+Space, and the GUI will tell you all the possible completions (and their explanations), one of which is ec.Ey . See screenshot attached.
This is one of my favorite new features at version 5.2a .

Best,
Jeff
Hello Rishad and Pu, Besides using the Equation View button, another approach consists in using the postprocessing tools, see for instance https://www.comsol.com/community/forums/general/thread/114702 . Another neat approach is now available in version 5.2a. We've added (or, to be more accurate I should say, we've greatly expanded) autocomplete. So, let's say you want to set the conductivity to "1+the y component of the electric field computed by the ec physics interface" but you don't know the syntax for the y component of the electric field computed by the ec physics interface. In the text field where you specify the conductivity, you can start typing "1+ec." then go Ctrl+Space, and the GUI will tell you all the possible completions (and their explanations), one of which is ec.Ey . See screenshot attached. This is one of my favorite new features at version 5.2a . Best, Jeff


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Posted: 8 years ago 08.07.2016, 11:10 GMT-4
Morning Jeff,

Thank you very much for your informative reply. I am trying to do exactly what you just said ! I am trying to vary the material conductivity with electric field component in y direction. Moreover, my conductivity here is an-isotropic in nature. So, in this case I would like to vary conductivity in x direction with electric field component in y direction.

However, I am using Electromagnetics Waves module, COMSOL 5.1 and I want to know whether you have the same facility in this version as well. I used emw.Ey to define E-field in y direction but still showing me an error.

Would you help me to define conductivity in x direction (anisotropic) as a function of Electric field in y direction for COMSOL 5.1? I have looking for these for hours and I am sure that I am missing something.

Thanks,
RA
Morning Jeff, Thank you very much for your informative reply. I am trying to do exactly what you just said ! I am trying to vary the material conductivity with electric field component in y direction. Moreover, my conductivity here is an-isotropic in nature. So, in this case I would like to vary conductivity in x direction with electric field component in y direction. However, I am using Electromagnetics Waves module, COMSOL 5.1 and I want to know whether you have the same facility in this version as well. I used emw.Ey to define E-field in y direction but still showing me an error. Would you help me to define conductivity in x direction (anisotropic) as a function of Electric field in y direction for COMSOL 5.1? I have looking for these for hours and I am sure that I am missing something. Thanks, RA

Jeff Hiller COMSOL Employee

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Posted: 8 years ago 08.07.2016, 11:26 GMT-4
Hi Rishad,
The autocomplete feature is new (or, again, to be more accurate, greatly expanded) at version 5.2a.
The other techniques discussed above should work at 5.1.
Best,
Jeff
Hi Rishad, The autocomplete feature is new (or, again, to be more accurate, greatly expanded) at version 5.2a. The other techniques discussed above should work at 5.1. Best, Jeff

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Posted: 8 years ago 08.07.2016, 17:08 GMT-4
Thanks Jeff for your response. I am trying to get some results, hope it works.

-RA
Thanks Jeff for your response. I am trying to get some results, hope it works. -RA

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Posted: 8 years ago 11.07.2016, 10:24 GMT-4
Hi Jeff,

I have tried vary the conductivity in x direction with 1+electric field in y direction, in COMSOL 5.1. I am not sure whether the physics is working or not. Would you please let me know how to do this in COMSOL 5.1 version. Please provide a screenshot of the conductivity tensor in this case for better understanding.

I have attached a screenshot to show I did it in COMSOL 5.1 version. Not sure though about the physics inside working or not.

Thanks,
RA
Hi Jeff, I have tried vary the conductivity in x direction with 1+electric field in y direction, in COMSOL 5.1. I am not sure whether the physics is working or not. Would you please let me know how to do this in COMSOL 5.1 version. Please provide a screenshot of the conductivity tensor in this case for better understanding. I have attached a screenshot to show I did it in COMSOL 5.1 version. Not sure though about the physics inside working or not. Thanks, RA

Jeff Hiller COMSOL Employee

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Posted: 8 years ago 11.07.2016, 10:28 GMT-4
Hello Rishad,
I am not an expert in EM. If your license is under a subscription contract, I invite you to contact COMSOL technical support at support@comsol.com .
Best regards,
Jeff
Hello Rishad, I am not an expert in EM. If your license is under a subscription contract, I invite you to contact COMSOL technical support at support@comsol.com . Best regards, Jeff

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Posted: 8 years ago 11.07.2016, 10:30 GMT-4
Please find the screenshot here.

-RA
Please find the screenshot here. -RA

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