[atulkjoy]

Hi,
I am trying to simulate a natural convective hot plume along the wall, wall is maintained at 300k constant. And wall is fully painted with radiation absorbing paint. I do not understand how to put wall radiation conditions.

I am using fvDOM model and medium is assumed grey and participating without scattering. schematic diagram is presented in picture.

My confusion is mainly about putting
emissivity uniform 1;
value uniform 0;
options in IDefault file
and in G file

Type marshakRadiation;
emissivity unifom 1;
CAn anybody tell me meaning and significance of these options ???

[Marpole]

You said the wall is fully painted with radiation absorbing paint. Thus it can be treated as a blackbody with emissivity 1. Is this where you get confused?

[atulkjoy]

I did but in OPENFOAM plus constant/radiationProperty/boundaryRadiationProperty there two options for absortivity n emissivity