I give this pair of inlet & outle boundary conditions, that velocity inlet and pressure outlet, in my case of simulating imcompressible flow of wind tunnel test. I am not sure this two problems:

Could both the operating pressure and the gauge pressure at outlet be set to zero?

And how to set the backflow k & epsilon? Just the same as the inlet ones，and how it effect the results? thanks.

Further to David's question, I need to know whether I can set operating conditions at different x & y coordinates? Please let me know if the outlet/ inlet pressure need to be set by "Operating Conditions" or at the time of initializing the solution? Thanks

I know "0" of gauge pressure at outlet means no pressure difference from operating pressure is. If you use 760torr as operating pressure, "0" of gauge pressure at outlet means pressure at outlet is same pressure as operating pressure. If operating presure is "0", pressure effect of flow will not be considered. So, this condition is improper for your model, you may need to change BC for outlet from pressure outlet to outflow. K and e at outlet is depending on your model. If your outlet is far from domain so that flow at this region is stable, and if there is no turbulence, use very small value such as 0.001. Thanks,

Ryu, My question is still unanswered. please advise! Thanks