THANKS !raback wrote: ↑23 May 2023, 12:01 Do not put "emissivity" for air. It does not make any sense. Air cannot have emissivity since it cannot have a surface. The radiating material should have emissivity defined. The direction of the normal vector will be set from the material that has emissivity defined outwards. For this reason emissivity for air leads to problems. Also, emissivity=0 is not a good idea because it is not physical. The equation for Gebhart factor will be impossible to solve then. All materials radiate. -Peter
It could have been so problematic ! thank you for the guidance !
I wish there was automathic correctives, like, if I set emissivity for air, then Elmer would have shown me some warning ! or explained to me as you did.