Preprocessing

Preprocessing

Quality Issue

    • Elfster85
      Subscriber

      Hi,


      So I'm trying to mesh my model C02 powered car in Ansys for a CFD simulation but it will only mesh successfully when the quality of the curve is very bad (as seen in the "no mesh error")..


      When I try to decrease the element size I keep getting an error but the curve is actually of high quality  ( as seen in the section plane on "failed mesh").



       


      Would really appreciate it if someone could help


      Thank you


      //Elvin Tiagi


      Mesh settings:




       

    • Keyur Kanade
      Ansys Employee

      Hi, 


      As ANSYS employee, I am not allowed to download attachments. 


      As per the images you have inserted, I can see a cut section of the mesh. But I can not see entire geometry or where mesh is failing. 


      If you are getting error in meshing, please use right click on the message and use go to problematic geometry. It may give location of problematic geometry. You may want to modify geometry at this location in DM or SpaceClaim. At the same time, you can use virtual topology if required. You can use local edge or face sizing as well. 


      Regards,


      Keyur

    • Keyur Kanade
      Ansys Employee

      Also you may want to look at 


      https://caeai.com/resources/tips-tricks-hex-brick-meshing-ansys-e-learning


      Regards,


      Keyur

    • Elfster85
      Subscriber

      Hi,


      Thanks for taking the time to reply! I've looked at the problematic geometry and it seems to be this:



      I actually use Autodesk Fusion 360 for CAD and I import in the .step file into ansys. This is how the geometry looks like (highlighted is the part ansys gives an error for):



       


      Do you think the hex meshing in the video will help me here or is it something else?


       


      Thank you


      //Elvin Tiagi

    • Rob
      Ansys Employee

      Have you split/subtracted the car volume from the outer zone? It's hard to tell from the images. Assuming that's the case is a cm scale mesh fine enough to capture the details of the car? 

    • Elfster85
      Subscriber

      Yes, I have subtracted the car from the outer zone. I don't really get what you mean by cm scale mesh.


      Thank You


      //Elvin Tiagi

    • Keyur Kanade
      Ansys Employee

      Hello, 


      The highlighted face may be the problem. From image it looks like it is a single curved surface. Can you please open geometry in SpaceClaim. Then split this face into more no. of faces, may be 3 or 4 faces. You can use Design -- Split command. Then check the geometry by selecting bodies in tree -- right click -- check geometry. 


      Following videos may help you. 




      Regards,


      Keyur

    • Rob
      Ansys Employee

      If you read through the settings you've used the minimum cell size is 1cm: as I don't know how big your object is I was checking that was suitable. The CO2 powered cars I've seen run off a soda siphon cylinder so are typically 5-10cm long.  

    • Elfster85
      Subscriber

      Hi,


      Its worked now! Thank you so much for helping me!


      //Elvin Tiagi

    • Keyur Kanade
      Ansys Employee

      Glad that it worked out!


      Regards,


      Keyur

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