2 Replies Latest reply on Jun 27, 2017 9:54 AM by Bill McEachern

    Flow Simulation Trajectories vs Surface Parameters

    Millen Anand

      I am looking for even volume flow through my part, but seem to be getting conflicting results from the visual flow trajectories and the numerical results from surface parameters in my flow simulations.



      Here is a photo of the flow trajectory. There is a single inlet (in this photo, at the back) set to an inlet volume flow, and 6 outlets set to environmental pressure. However, as you can see, the flow is visually only through 5 out of 6 outlets, and is certainly not even. I originally thought this was a rendering issue, and attempted to run the simulation again with higher global and local mesh values, which didn't help.


      Yet, when I open Surface Parameter Results for the lids of the inlet and 6 outlets, the outlets are more or less even in terms of volume flow rates.


      What is happening here? Should I trust the flow trajectories or surface parameters?

        • Re: Flow Simulation Trajectories vs Surface Parameters
          Amit Katz

          I would trust the surface parameters over the trajectories.


          The flow trajectories are back-calculated from the mesh through points picked out by the software on the chosen face. There are also a limited number of trajectories, so that's why you're only seeing them from certain inlets.


          If you want to see how the trajectories interact, you could do 6 studies (one for each inlet) and color each one of them a different solid color. Pick ones that will stand out from each other: red blue yellow etc... Make sure you pick the same number of trajectories for each calculation. That will allow you to see how the six inlets mix and flow through your manifold.

          • Re: Flow Simulation Trajectories vs Surface Parameters
            Bill McEachern

            what you get in a flow trajectories plot depend on what you pick for the source and its mesh properties amongst other things... You can get really good looking ones if you put in an pick surfaces at each outlet and ask for the same number of low trajectories from each. This would look  even you the flow were vastly different. Hopefully you get the point.