[Sarath Chandran R]

I am trying to complete my final year project as a Mechanical Engineering student on the topic, "Heat dissipation through perforated aluminum fins".

I validated a forced convection study in my system and has started performing my own analysis. On my already created heat sink geometry(for paper validation), I added circular perforations and tried to run the same simulation as i did for the paper I validated. What I mean by that is that I didn't do any additional steps for my analysis other than modifying the geometry (no subtraction to create fluid domain for air to pass through as I had already done it initially). The meshing went smoothly but as I entered setup I encountered a problem. For the modified geometry i had two or more extra boundary condition options compared to the initial one. These are interfaces(I think) for which i don't know which option to choose from. I usually go for 'coupled' option in such cases but that option isn't available. I have been stuck here for days now and my runs have been unsuccessful.

So I have a few questions.
1. Can I not use the same geometry used for paper validation and modify it to my needs, should I do my analysis from scratch and do subtraction process(since geometry is different)
2. What should I do about the extra options in Boundary Conditions.
3. Is there anything else I need to be aware of in this scenario.