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define vector

Posted Jun 29, 2012, 8:21 p.m. EDT Version 4.2a 4 Replies

Joquin Santos
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hello
I have seen some physics modules in comsol: acoustics, mathematics, etc
the dependent variable "u", psi, fi, v etc, is a scalar
how to define those dependet variables, for example "u", as a vector?

thanks
4 Replies Last Post Jul 1, 2012, 5:04 a.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Jun 30, 2012, 3:42 a.m. EDT
Hi

that is not fully correct, "bold" u is a vector, generally expressed as the triplet (u,v,w), COMSOL mostly references in the text to the vectors in bold but in the programme we work with the scalar comonents.

One of the difficulties(I find) is that COMSOL's notation adds a lower case suffix "x" ,"y", "z" or "r" "phi" both for the spatial derivative, and for the coordinate components, its up to us to identify when which applies. But I believe they are migrating towards a 1,2,3 suffix for spatial and x,y,z for the derivatives, but this will certainly take time, as there are houndred, if not a tousand variables predefined, you need to change all habits of the users, and provide translation scripts

Use the preference equation view to get the naming conventions and definitions, or just read the new 4.3 doc, most variable names are now described


--
Good luck
Ivar
Hi that is not fully correct, "bold" u is a vector, generally expressed as the triplet (u,v,w), COMSOL mostly references in the text to the vectors in bold but in the programme we work with the scalar comonents. One of the difficulties(I find) is that COMSOL's notation adds a lower case suffix "x" ,"y", "z" or "r" "phi" both for the spatial derivative, and for the coordinate components, its up to us to identify when which applies. But I believe they are migrating towards a 1,2,3 suffix for spatial and x,y,z for the derivatives, but this will certainly take time, as there are houndred, if not a tousand variables predefined, you need to change all habits of the users, and provide translation scripts Use the preference equation view to get the naming conventions and definitions, or just read the new 4.3 doc, most variable names are now described -- Good luck Ivar
Joquin Santos
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Posted: 1 decade ago Jun 30, 2012, 11:44 a.m. EDT
Hi,
I'm using 4.2a version
and I'm using the maths module where the variable "u" is not bold.
it would suit to me to define it as a vector, how to do it ?
Hi, I'm using 4.2a version and I'm using the maths module where the variable "u" is not bold. it would suit to me to define it as a vector, how to do it ?
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Jul 1, 2012, 4:44 a.m. EDT
Hi

no the "bold" is only in the text, check for u,v,w in the dependent variable tab of the main physics

--
Good luck
Ivar
Hi no the "bold" is only in the text, check for u,v,w in the dependent variable tab of the main physics -- Good luck Ivar
Joquin Santos
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Posted: 1 decade ago Jul 1, 2012, 5:04 a.m. EDT
got it
thanks
got it thanks

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