Abnormal pressure comparing to fluent
 

I am simulating a pipe flow with cavitation physics. The inlets and outlets cannot be defined as pressure conditions according to the current available data. Mass flow rate at the inlet and continuity at the outlet are in use. The solver will report "there is no reference pressure available".

When using velocity inlet and outflow outlet conditions both in fluent and flow3d, the results are quite different. The range in Flow3D is wider and the value is much larger.

How to make the two results with the same value within an acceptable discrepancy.

Is there a possible way to define the reference pressure without defining the pressure boundary conditions? Void pressure does not work.

Thanks if there is any help.