I am working on flow through porous media. Flow characteristics can be solved using Brinkman Equations physics and Heat Transfer characteristics can be solved using Heat Transfer in Porous Media Physics. When I defined 2 materials - air(fluid) porous material (solid) for the same domain, Air is asking to input permeability and porosity for it (mandatory) which is undesired. Is there any way to skip this?
It appears you need to define two sets of material properties for one domain for solving two different physics. I'm not sure if you can define 2 material for one domain, but what you need can be achieved in a different way. In defining the physics interface, you have the option get a value of a certain property, "from material" or can specify "user defined". If you use the 'user defined' option, I guess you should be able to achieve a fluid for one physics and a solid for the other. I'm not familiar with the physics interfaces you are talking about, but with wave optics module I have assigned different material properties to different domains by either assigning different materials to different domains, or alternatively without assigning any material for the domains but defining the required material property for each domain at the 'user defined' option in the physics interface itself.
Well, COMSOL is - let's say - a little bit "simple minded", as soon as it comes to material property definition. For us, it is obvious, that a porous media consists of at least two different domains: void space and matrix. So, obviously, void space has no material parameter like "porosity or permeability" and the matrix in this setup neither. You can set these parameters to zero since you "move" the entire void space volume by applying a pressure drop or other inflow/outflow conditions.
As Mr. Halisch said, there is just one material per each solid. What I advice to you is making use of the booleans operators, you can define 2 different solids, block + bubbles and then subtract the bubbles from the block, and add the bubbles as another you can join them. Following that procedure you can have the two different materials in the solid.
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