Discussion Forum

Hi

then green marks are the link between all the possble material properties, and thus identified by COMSOL based on the physics applicable to the domains where you attribute the material. So for some reason you have not (yet) linked the material to a domain (or if applicable to a Boundary for thin layer BC physics) such that COMSOL has not identified "n" as a required variable.

In RF optics there is a second possiblity: if your "physics" is defined using the epsilon_r material property, instead of the optical n,k properties, this might happen, but then there is a green mark for epsilon_r, if so, go to the physics node for the relevant domain/material and change the physics from epsilon_r driven to n,k driven, and that should do the job

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Good luck
Ivar

Hi Mr. Ivar.
I am having the exact same problem.
You describe:
(...)if so, go to the physics node for the relevant domain/material and change the physics from epsilon_r driven to n,k driven, and that should do the job.

But how can I 'change' the physics?
I cant' read anywhere where epsilon_r driven is?
and I can't insert n,k driven anywhere?

I am working on extraction of oil out of a chalk reservoir and I must analyse the if extraction rate changes with increasing reservoir temperature. The reservoir is modelled as a porous medium to where I have defined its permeabilities and porosities, and the model works out fine with this.
I have tried to add a temperature in Basic Properties but it never comes out with a green -ok sign.
I also need to add Mohr-Coulomb (cohesion, friction angle) and they also appear in the Output properties, but never become green.
So my problem is assigning them to my already working reservoir.

Can anyone help please?

/Lasse

Hi

could you be a bit more specific PLS ;)

which physics and which COMSOL version ?

When you say you add the "T" variable, is it a material dependence on "T" you are adding, or are you trying to add T as variable in the material section ?
The latter will NOT work, because "T" is not a material property, rather a dependent or defined variable depending if you are also using the HT physics.
Without any HT or other physics defining "T" you should add a value T in the Parameter (or the definition variable node). And then vary T (i.e. as a parametric sweep, and i.e. have a T dependence in your material data

My previous comment applied to RF/optics physics, where you can choose the way you use the material properties. Such options are in the main physics or the first sub-nodes of many physics. i.e. structural you can choose different material properties E, nu, G, K, Lamé constants ...

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Good luck
Ivar