Hi. I have an electronic enclosure that is cooled by natural convection. I ran simulations to calculate the temperatures in the enclosure. I wanted to see what the effect of the box being in low pressure so I added the vent holes to my model and set a **boundary condition** on vent holes (actually on the lids for the holes), to **75993.75 Pa**, after running the pressure on the surface is between 759993.55 Pa and 75993.65Pa, I realize this is a minuscule difference and within error of the program, BUT shouldn't it be exactly 75993.75? thanks for your thoughts.

My guess:

Simulation first estimate the body of the box with mesh which will not be 100% if there is any curve, circle, arc.

Hence result is not 100%.