[flow_CH]

hello

I am modeling a open channel flow in fluent with using open channel BC.
I don't know every time i am using that BC in simulating, there is no fluid into the modeling zone after steady simulation. I am defining reference pressure in 0,0,0 coordinates and in other levels but it don't works. What is reference level in defining free surface and bottom of channel in BC? may be i am defining incorrect that?
My BC in inlet is pressure inlet with inlet ID =1 for air and water (together) and outlet is pressure outlet with gauge pressure=0
thanks