Incident Radiation
 

Hi,

I'm doing some sensitivity analysis on altering the absorption coefficient a subdomain, and am getting a bit muddled trying to figure out the actual impact.

The set up is as follows (and shown in the attached image):
A 100W/m2 directional radition source is applied to an opening (inlet), set at 303K fixed temperature, with a very small velocity to aid convergence. 10metres away, the opening (outlet) is set to the same fixed temperature. All other surfaces are symmetry planes, there is no buoyancy, and the Monte Carlo radiation model is set.

In the results file, the incident radiation for a zero absorption coefficent on the xmax face is around 2008W/m2, and similarly for the xmin face. When the radiation source is set to zero, the incident radiation is reduced to 1909W/m2 on the inlet and outlet, confirming the 100W/m2 difference. My question is, where is the other 1900W/m2 coming from??

Thanks in advance,

Nicki

Sorry, worked it out. Basic Physics!!