I am trying to calculate the flow rate of oil in a 3-phase flow from OpenFOAM at the outlet. It is not correct so I tried it at the inlet where I know the flow rate of water. I used the following filters:
Cell size ==> Calculator ==> Integrate variables
The calculator formula is areaU_water.xalpha.water
The actual flow rate is 1.2 E-3 m3/s
The flow rate calculated following integration is 1.83 E-7.
If I sum the column in the spreadsheet from the Calculator filter I get 1.16 E-3 (close to the known value, 3.3% different), so it appears that the Calculator filter is correct but the Integrate Variables filter is not.
Any suggestions?