[Explorer]

I'm simulating air flow through an underground tunnel. Flow velocity is determined by heat transfer from the earth surrounding the tunnel. The only changing variable between simulation cases is the temperature gradient between the "earths surface" and the bottom of my domain (50m deep) by altering the ambient temp at the surface (Ts). This (Ts) is also the temperature at the inlet and outlet boundarys.

My question involves setting pressures during set up....

I have a 0 gauge pressure at the inlet and outlet of the tunnel, and have the operating pressure in "operating conditions" set to 1 atm at x0,y0,z0 (located at the inlet). I am confused about the meaning of the reference pressure under the "reference values" menu. I am new to Fluent (sorry!) and overlooked this at first...

Is this Ref. Pressure used in calculating results at all? Or is it only used in post processing? - the reason I ask is having seen that the ref. Pressure can be set at each boundary (using "compute from" drop down list) it does not jump at me as being the 'reference pressure' (as operating pressure does).

Any more info needed?

Thanks!