Measuring mass flow rate through a surface

- February 27, 2023 at 5:16 pm
  
  Fernando Hernández
  Subscriber
  
  Hi there!
  
  I am currently performing a 3D analysis of a Formula Student car. The objective is to measure the air mass flow rate that passes through the sidepods, so I have created a surface at the sidepod entry and I have defined a Surface -> Mass Flow Rate report on that surface.
  The X velocity contour can be seen in the attached picture (I have assumed that the dark spots are just a visual glitch, but maybe I'm wrong). The area of the surface is around 0.1 m2. So according to my calculations the mass flow rate through it should be around 1 kg/s.
  
  However, as seen in the next picture, the resulting mass flow rate varies between 0.015 and 0.025 kg/s.
  Am I doing something wrong? Is this mass flow rate measuring method incorrect?
  I would appreciate any help. Thank you in advance.
  Kind regards!
- February 28, 2023 at 11:20 am
  
  Rob
  Forum Moderator
  
  You may need to run a few more iterations. Most real models don't converge in 180 iterations. How do the residuals look?
  Please replot the contour with node values off, that's a good way to check the mesh resolution.