Cavitation of an Orifice Plate in Pipe System

CFXuser

I'm doing a quick CFD analysis to assess whether a orifice plate will cavitate within a pipe network. I've just modelled up a straight horizontal tube with the orifice plate in the middle with a hexa mesh and applied a fixed mass flow rate to the inlet and a static pressure on the outlet (1bar). The solution solves pretty quickly to nice low residuals.

I'm going to assess the likely onset of cavitation by comparing the computed pressure field with the vapour pressure of water (obviously this is only a quick fix way of predicting cavitation, since the onset can be triggered at much high local pressures if the conditions are right).

I know I need to add the hydrostatic pressure contribution (pgh) to the solution in CFX-post i.e. the pressure change from the top to the bottom of the pipe. Depending on what extra pressure terms you add can seriously affect the onset of cavitation. However, do I also need to add any further pressure terms to the field relating to the driving pressure/head due the actual location of the orifice plate in the whole piping system.?

Any tips/pointers would be appreciated.