Page History

...

Make sure air is selected under Fluid. Double click air, set Density to ideal-gas and make sure Cp is constant and equal to 1006.43 j/kg-k. Also make sure the Molecular Weight is constant and equal to 28.966 kg/kgmol. Selecting the ideal gas option means that FLUENT will use the ideal-gas equation of state to relate density to the static pressure and temperature. 

Click Change/Create.
Define > Operating Conditions
To understand what the Operating Pressure is, read through the short-and-sweet section 8.14.2 in the user's guide. We see that for all flows, FLUENT uses the gauge pressure internally in order to minimize round-off errors. Any time an absolute pressure is needed, as in the ideal gas law, it is generated by adding the operating pressureto the gauge pressure:

...

Set the Gauge Pressure to 101325. Set the Mach Number to 3. Under X-Component of Flow Direction, enter a value of 1 (i.e. the farfield flow is in the X direction).
Next, click on the Thermal Tab. Change the temperature to 300K.

Image Modified

Click OK. The pressure-far-fieldboundary type effectively imposes that there is no upstream propagation of disturbances if the flow at the boundary is supersonic. See section 7.9 of the FLUENT help for more details about this boundary type.

...