Hello Rob,

Thanks for the reply.

In the energy equation, we can add volumetric source terms (W/m^3). In S2S radiation model, I have not mentioned any source term value. 

If the model itself estimates the source term and adds in the energy equation, then will it add in the energy equation of fluid or solid?

If it is added as a source term, can you please describe how it is calculated per unit volume? And is it added in the neighbouring one layer of cells next to the boundaries participating in radiation exchange or where is it added?

I request you to kindly clarify these doubts.

Thanks and Regards,