Negative Total Pressure in cavitatingFoam RAS/Throttle Case in OF 1.6
 

I'm working on modelling cavitating flow in a series of control valves, and my plan was to use cavitatingFoam to do so. However, when running the "Throttle" tutorial case in the "RAS" subfolder, I noticed that the total pressures (calculated using ptot utility) go negative which seems unphysical. I know that in some other CFD solvers there is a reference pressure somewhere, does OpenFOAM use anything similar? If not, can somebody explain why the negative pressure shows up?

same problem...
 

I need to simulate the cavitation in an injector. To get more familiar with the code dedicated to the cavitation in openFoam, I try to run the throttle tutorials case.
I also got some negative value for the pressure. Moreover I can observe some backflow from the outlet and a kind of pressure wave... I don´t know how to solve the problem. If you have any idea, would be great!
thx