[er_ijaz]

Dear Sir/Madam,


Thank you so much for answering my previous query. I have one more doubt.


I need to run a simulation of a pipe (closed system) with rectangular cross-section. Water enters at 0.3 m/s but we are not sure about air so I used zeroGradient.


Initially I find ref cell id for one cell in air inlet (from paraview) and set prefcell and prefvalue is zero (atmospheric pressure) but while running the simulation, after certain time the value changed to negative and the hydrostatic pressure at the bottom wall was in relative to the negative pressure.


Since we wanted to get the exact pressure value to be provided to civil team, we set p_rgh to be fixed value (height chosen was inlet height), but what we noticed that immediately after the inlet there is a small shock like structure and there is a velocity and pressure drop. We are not sure whether to continue the run.


Kindly please advise us, what to do to get the absolute pressure value on the bottom wall of the pipe?


Regards
Dr. Ijaz Fazil