Mass flow rate evaluation using Plot Selections Over Time


I use OpenFOAM for simulation of water transport in pipes by VOF method and ParaView for post-processing of the results. I am facing face with the problem in ParaView when I am trying to evaluate water flow rate through custom cross section in the pipe. In my geometry there is small siphon with water in front of desired cross section. Coming air pushes this water downstream of the pipe causing splashing, so in this case water flow through the cross section is not continual. When I try to evaluate flow rate value for each time step it works perfectly with different options (by integration of water velocity field or using Surface Flow filter). But when I try to use filter Plot Selection Over Time to get flow rate evolution in time I get the message that “Input and Output data array do not match” or “Type mismatch: Source: double Dest: idtype”. It seems that for time steps when there is no water passing the cross section ParaView excludes the column from the array instead of putting 0 value. When I was using the 3rd version of ParaView I’ve found that if I multiply flow rate value by 1 in the calculator then ParaView put in the array 0 values. Now I am using 5th version and similar manipulations do not work. I’ve checked all available information in the web regarding this problem but unfortunately haven’t found possible solution. That is the reason why I’m writing to you. I would appreciate any hints or recommendations which could help me to solve this issue.

Thank you very much in advance.