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Mesh Element Area

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Are there operators available to find the area per face of a 3D element?

Say that I want to find the total current flowing through an element and use it in an expression elsewhere. For instance, nCurrent = es.Jz*elementArea

I have browsed through the API Reference, and there appears to be enough operators available to write a MATLAB function to calculate total area per face on a 3D element, but I want to verify this is the best way to proceed.

Is there an easier way than writing my own function?

1 Reply Last Post Feb 10, 2011, 3:11 p.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Feb 10, 2011, 3:11 p.m. EST
Hi

I'm not sure I catch youre question copletely. You have the element dvolume defined, the size "h" too (chhck the doc), but if you have noticed the units most COMSOL values are densities, hence variales to be applied to a "mesh" elemen of size dx*dy*dz (in 3D). ANd wehumans talk mostly about absolute values an not densities. YOu must integrate these densities over the doamins or boundaries to get the macroscopic values.

Another though: if you integrate i.e. a current density to get the total current, and then distribute this current over another model boundary, then you average out the value, ie.e you new model has an average value spread evenly over the full boundary, and probably not the true current profile from the first model. To link two models profiles you need to map (extrusion or projection coupling variables) the two models at the "density" level applied to the elementary mesh eleent (hope this is expressed in an undestandable way)

--
Good luck
Ivar
Hi I'm not sure I catch youre question copletely. You have the element dvolume defined, the size "h" too (chhck the doc), but if you have noticed the units most COMSOL values are densities, hence variales to be applied to a "mesh" elemen of size dx*dy*dz (in 3D). ANd wehumans talk mostly about absolute values an not densities. YOu must integrate these densities over the doamins or boundaries to get the macroscopic values. Another though: if you integrate i.e. a current density to get the total current, and then distribute this current over another model boundary, then you average out the value, ie.e you new model has an average value spread evenly over the full boundary, and probably not the true current profile from the first model. To link two models profiles you need to map (extrusion or projection coupling variables) the two models at the "density" level applied to the elementary mesh eleent (hope this is expressed in an undestandable way) -- Good luck Ivar

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