Applying formulas to boundary conditions - roof conditions

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I am trying to find a way to apply different formulas for boundary conditions to a surface.

We are trying to model the impacts of micro-climate on a large roof. We are using CFD to look at how the surface temperatures and co-efficients of convection are affected for different conditions. Typically surface temperatures are higher than would normally be predicted by thermal modelling, and the convection patterns are different.

Ideally I would like to change the boundary properties of the roof based on the relationships we find through the CFD. It seems that I would need to change the modelling of convection to match the values found in CFD, and maybe long-wave radiation (due to different surface temperatures). Direct and diffuse radiation would be normal, and conduction into the space should be able to be calculated once the other properties are known.

I have tried looking into OtherSideCoefficients, but this removes the solar contribution, and only allows fairly simple relationships to be included - no custom formalas. Is there a way to input different formulas for the boundary conditions for a surface?

Thanks for your assistance