how to get the right pressure value in the backflow domain?
The 3D model i finished is as following figure.The water flows into a pipe with different diameters.Inlet boundary type:velocity inlet(2m/s), outlet boundary type: 0pening(0Pa).
In CFXPost,i got the presssure values of several faces as follows[areaAve(pressure)@plane]: INLET PLANE1 PLANE2 PLANE3 OUTLET static (79 ) (170 )(153 )(1.56) (0.00019) pressure total (1343 )(79 )(70)( 7.36)( 5.6) pressure the question: 1)why is the total pressure on plane1 and plane2 negative? 2)How to get the right pressure value on the plane located in the backflow domain in CFXPost? http://forum.simwe.com/data/attachme....jpg.thumb.jpg 
anyone can give me an answer?Thanks very much.

The recirculations at plane 1 and 2 are low pressure, low velocity regions where a lot of energy is lost, so the pressure is low.

why is the total pressure on plane1 and plane2 negative?(the reference pressure is setted as 0Pa or 1atm,and the value is the same.)
The plane 1 and 2 is in the backflow domain,and I get the pressure value using areaAve(total pressure)@plane1,is it right? The pressure drop between inlet and plane1 is equal to areaAve(total pressure)@inletareaAve(total pressure)@plane1? 
The value is caculated using areaAve()@.
this following table gives the values using ave()@ INLET PLANE1 PLANE2 PLANE3 OUTLET static (80 ) (164 )(168 )(1.46) (0.0008) pressure total (1342)(393)(338)( 8.95)( 5.07) pressure This following tabe gives the values using massFlowAve()@ INLET PLANE1 PLANE2 PLANE3 OUTLET static (79 ) (156 )(165)(1.52) (0.00022) pressure total (1343 )(1269)(1171)( 7.79)( 5.7) pressure There are big different for total pressure value between the three tables in backfow domain,but the static pressure is approximately same.which is right for the case? Thanks in advance for your answer. 
Before wondering about what a result means, have you checked it it accurate? See this FAQ for tips:
http://www.cfdonline.com/Wiki/Ansys..._inaccurate.3F ave(), areaave() and massFlowAve() all integrate different quantities, so the mesh size and mass flow rates are skewing the results. 
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