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Time function of the lightning current

Posted Jan 11, 2022, 10:46 a.m. EST Electromagnetics, Low-Frequency Electromagnetics Version 5.6 6 Replies

Mateusz Buda
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Hello, I will wonder if someone explains to me how to add lightning current function in COMSOL. I was trying to use the ‘analytic function’ node from the definition section of the COMSOL to provide the time depending function of the lightning current (for analysis purposes). Unfortunately, I did not achieve anything that has any sense. The equation which characterised this function is: i=I/k×(t⁄T1)^10/〖1+(t⁄T1)〗^10 ×exp((-t)⁄T2) Another thing is how to use this function as an input to the terminal of the metal structure (all in 3D simulation)?

6 Replies Last Post Jan 31, 2022, 2:02 p.m. EST
Edgar J. Kaiser Certified Consultant
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Posted: 2 years ago Jan 12, 2022, 6:08 a.m. EST

Mateusz,

it should be straightforward to implement the analytic function. What is the problem in detail?

Cheers Edgar

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Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Mateusz, it should be straightforward to implement the analytic function. What is the problem in detail? Cheers Edgar
Bouderbala Abdelkader
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Posted: 2 years ago Jan 30, 2022, 7:41 p.m. EST

I have the same problem

I have the same problem
Dave Greve Certified Consultant
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Posted: 2 years ago Jan 30, 2022, 8:34 p.m. EST

Posting your (reduced) model will yield the most informed responses.

However- when simulating very abrupt and short transients it is important to choose the time stepping settings carefully.

Posting your (reduced) model will yield the most informed responses. However- when simulating very abrupt and short transients it is important to choose the time stepping settings carefully.
Bouderbala Abdelkader
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Posted: 2 years ago Jan 31, 2022, 9:04 a.m. EST

The problem is, I don't know how to enter time-varying data into the comsol

The problem is, I don't know how to enter time-varying data into the comsol
Bouderbala Abdelkader
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Posted: 2 years ago Jan 31, 2022, 9:07 a.m. EST

Did you find a solution to this problem?

Did you find a solution to this problem?
Jeff Hiller COMSOL Employee

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Posted: 2 years ago Jan 31, 2022, 2:02 p.m. EST
Updated: 2 years ago Jan 31, 2022, 2:06 p.m. EST

Hello Bouderbala,

The COMSOL GUI is interpreted, so you can type mathematical expressions in the user interface pretty much like you write them on a piece of paper. This has been discussed many times in this Discussion Forum (For instance, here ), and for an extensive discussion of the syntax and available function I will refer you to the documentation, which is accessed through File > Help > Documentation in the software itself. When solving a time dependent problem, "t" is time.

Best regards,

Jeff

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Jeff Hiller
Hello Bouderbala, The COMSOL GUI is interpreted, so you can type mathematical expressions in the user interface pretty much like you write them on a piece of paper. This has been discussed many times in this Discussion Forum (For instance, [here](https://www.comsol.com/forum/thread/122051/error-while-calling-external-c-function?last=2016-08-26T11:03:59Z) ), and for an extensive discussion of the syntax and available function I will refer you to the documentation, which is accessed through File > Help > Documentation in the software itself. When solving a time dependent problem, "t" is time. Best regards, Jeff

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

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