I am NOT getting right pressure at the air inlet in water column
 

Problem Description:

Find the static pressure at the air inlet which is at the bottom in steady state condition for the container is completely filled with water initially. Kindly refer the attached picture for the problem understanding.

Simulated Condition:

1. Software Used: Ansys Fluent
Eulerian Multiphase Model: 2 Phase (Primary phase: water, secondary phase water with 0.0002mm dia)
2. Inlet Bounadry Condition: Air Velocity (very high velocity) with VOF 1; water velocity with 0 m/s
3. Outlet boundary condition: Pressure Outlet (0 gauge pressure and VOF 1 for secondary phase back flow)
4. Initial Condition: Entire domain is completely filled with water: VOF=1
5. Decent mesh size is there to capture the effect of velocity gradients

5. Solved by steady state and transient as well.

5. After solving, I obtained negative pressure when I did post processing with CFD post. But it should be of any negative pressure at the inlet in reality.

Kindly help if there is any problem in my boundary condition set up or multiphase model selection. Thanks in advance.

Thanks& Regards, Raj