3 Replies Latest reply on Oct 15, 2015 9:45 AM by David Flemming

    Flow seems to be going through thin wall

    David Flemming

      Hello Everyone,

       

      I'm running a simple CFD analysis on a thin walled component. It's an internal analysis and the component has some thin sheet metal parts in it. The analysis runs ok but when I look at a trajectory plot I see that some of the trajectory lines are going through the thin sheet metal walls of the component.

       

      Is this normal or is there a parameter that I have to adjust to take care of this?

       

      The Small solid feature refinement level is set to 6 and Cell refinement is on 4.

       

      Thanks,

      David

        • Re: Flow seems to be going through thin wall
          Chris Michalski

          Likely your mesh is too coarse and the particles are moving so fast that they jump from one side to the other without being calculated as in the solid first (at which point they would stop).  Does your mesh resolve those thin walls?  If not you could try adding planes in the mesh that are in those walls so that it recognizes them as partial cells and improves the accuracy of the trajectories.

          • Re: Flow seems to be going through thin wall
            Amit Katz

            I have seen this issue before as well, it only shows up in the trajectory calculations. When I check the velocity magnitudes and the vectors I see that the flow and the walls interact in expected ways. I'm not sure what exactly causes the issue, I usually just ignore it.

              • Re: Flow seems to be going through thin wall
                David Flemming

                Thanks for the response guys...I refined the mesh some more and increased the solid/fluid interface level as well and there was some improvement. Went from about 200,000 cells to 550,000 cells.

                 

                As Amit says, the flow is reacting as expected, I believe the problem is that the wall are so thin that it only appears that the flow is crossing the wall but it actually isn't. It's just running along side the wall. I think it is just a matter of the trajectory position accuracy.