I’ve used a pressure-outlet but reversed flow still occurs.

then what do I change is this correct? i expect the flow to move to the positive x-axis but due to reversed flow, the flow is inlet to the negative x-axis

this is the expression of the parabolic formulation that I use
umax = my velocity 11.96m/s
radius =  sqrt(x**2+y**2)
Radius = area (0.03m)

uprofile = umax*(1-(radius/Radius)**2)

and this is the geometry that I analyzed where convection occurs in the middle of the box in the air flow