[Leoma]

Hello,


I am currently facing the following problem. I have a body with many channels, where air is flowing around/through it. I want to determine the massflow inside the body, hence I made a named selection of the opening of the channels (internal surfaces). Due to the missing symmetry I cannot create a plane in Post. However, I noticed that the massflow was too little and saw that some faces of the named selection had a different face normal vector (1,-1), which resulted into the wrong massflow. I tried the following ways to calculate the massflow:


=areaInt(Density*Velocity u)
=areaInt(Density*Velocity u * step(Normal X))+=areaInt(Density*Velocity u * step(-Normal X))


and a variation where I calculate the Vdot (u*X+v*Y+w*Z) and then again the areaInt.


These calculations are about 3% off from the ideal massflow (which I got from a toycase, where I can just create a plane and calculate the massflow). Can you help me find my error or do you know a way to direct all face normals in a named selection in one direction?


Thanks in advance!
Best,
Leo