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Lorentz Force - mf.FLtzz
Posted 2017年11月12日 GMT-5 18:55 Low-Frequency Electromagnetics, Parameters, Variables, & Functions 1 Reply
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Problem: Unknown variable mf.FLtzz Cannot find list of predefined operators in Documentation
Context: I have version 5.3 My only component is 2D axisymmetric I have added Magnetic Fields (mf) and ODEs and DAEs (ge) Physics Interfaces I have defined an integration over a domain using Component Couplings I am trying to define a Variable: Integration operator(-mf.FLzz2pi*r) *(italics?) I get the error: Unknown variable mf.FLtzz
Further Details: Following instructions for models.acdc.falling_magnet.pdf - 0.75MB _ Found instructions at: https://www.comsol.com/model/magnet-falling-through-copper- tube-13875 I am at 'Variables 2' step 3. and have double checked that I followed all other steps sucessfully.
Where I have looked after searching through other discussion forums: In: File->Help->Documentation->COMSOL Multiphysics Reference Manual->Global and Local Definitions : I have looked in the following: 1. All sections in Operators, Functions and constants 2. All sections in Predefined and Built-in Variables 3. All sections in Magnetic Fields Interface
I searched 'mf.FL', 'mf.FLt', ... 'mf.FLtzz', etc. and there were No Results Found in the Documentation I searched 'Lorentz' in Documentation and reviewed a number of links to no avail
Does someone know where I should be looking? Thank you
P.S. Apologies for formatting, Hitting RETURN apparently did not force a line break unless I hit it twice and I could not put in underscore or multiplication symbol without toggling italics.
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Hallo Liam,
I do find mf.FLtzz but, depending on your material type settings it could by ending in ZZ, ie capitalize letters.
But I think the main question is: How to find out?
I like the "Equation View" nodes in the physics tree. You need to activate it: in the model view at the top there is an icon with an eye. There is a long list in that case, but your can find Lorentz force towards the end (and learn at the same how it is calculated).
Another way is the result section. For this to work you need a solution object, an initial solution is enough. Then create a surface plot in 2D and where you enter the expression field there are the buttons "replace expression" and "insert expression". There, all available variables are listed. There are many, but your can find what is really defined and how it is called. You can copy the name and use it in your expression.
Regards,
Jens