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CFD FSAE Meshing errors/fail – How to search for coordinates – MRF issue

    • kelvin.k.kong
      Subscriber


      EDIT 2: Solved surface mesh issue! I did not subtract the car body from the enclosure, and I did named selections on solids instead of under the Enclosure surfaces (with Enclosure hidden).
      I still would like to know how to search for coordinates of issues. Another issue is that I have is with the MRF zones. (See below)

      Dear Staff and fellow forum users,

      I'm trying to following this Ansys learning CFD Learning series.
      Importing PMDB file from Discovery to Fluent.
      I cleaned up my model using repair and prepare tabs.

      2 Question of mine:

      Q1) How to search up the coordinates in Fluent/Discovery to locate the areas of the parts that are causing the issue?
      Or any other way to see the issues on the car model?
      Example:

      Error: Failed to project bn3211 bn3211 (front-edges) onto face (-24.218202 289.260000 425.452949) .

      Following the video series, I've created local refinement regions for the front and rear wheels, and three body of influences, created a local sizing for the 'chassis' of the car (everything minus the wheels).

      Understandly, error object #f is a meshing problem.


      EDIT:
      I think I might know what went wrong. 
      At ~12:45min of this video , the lecturer did 'hide all suppressed' to hide the body of the car, to be subtracted from the enclosure (I guess?). Which I didn't do previously. 

      Question - Regarding MRF Zones:

      Regarding MRF zones made in Discovery, and Following this part of this video:
      This part of the previous video from above shows the front and rear MRFs as solids, and included in simulation, which I had done.
      But my MRF zones does not automatically pop up under 'update regions'. 

      From video:


      My screenshot:

      Instead, apart from the enclosure, I have parts called fluid, which are my suspension arms and brake components. (I'm confused!).
      Any reason why this is happening for me?

      Also in Discovery, my MRFs are inferencing with my rims, via (interference and duplicate tools).
      I reckon my overlapping error messages is regarding this! What can I do about this?



      Many thanks!

    • Hemantg_17
      Ansys Employee

      To search for coordinates in Fluent, you can use the following method: In Fluent, click on "File > Write > Profile" and write the coordinates on the surfaces you want to compare. This allows you to export the node locations to a text file, which can be useful for comparing meshes or locating specific areas - https://ansyskm.ansys.com/forums/topic/is-there-any-easy-way-to-check-the-mesh-in-the-fluent-same-as-the-mesh-in-meshing/

      While , In Discovery, you can enter the coordinates directly or define the point's origin by clicking "Set remote point location" and selecting a geometry. This feature allows you to specify a point in space for various operations, such as applying displacement or force.Also you can define a point at given coordinates and check the planes for example, check planes at  (-24.218202 289.260000 425.452949) .

    • Hemantg_17
      Ansys Employee

      Regarding the duplicates, use the duplicate tool in discovery and remove the duplicate solid part. Ensure that you have removed the rims from MRF regions (this might have been mentioned in the video). Assign the MRF regions properly and check it again.This will solve your issue.

       

      • kelvin.k.kong
        Subscriber

         

         

         

        Hi Hemantg,

        thanks for the quick replies.

        About the MRF Regions, I am confused what is the difference between MRF and interfaces for the named selections? 
        (From ~12:06min in this vid)
        I don’t know how to obtain the faces for the interfaces. It’s not clear in the video. 
        Is the Solid MRFs named Interfaces or MRFs in the named selections?

        EDIT: Managed to use duplicate tool to form the correct mrf!

         

         

         

    • Hemantg_17
      Ansys Employee

      You can download the geometry provided with the course and check the difference between MRF and Interfaces in this case. And yes, you can use/put them under your named selections. Please follow the course link to get the geometries: Aerodynamics of an FSAE Car | Ansys Innovation Courses

      • kelvin.k.kong
        Subscriber

         

         

         

        Oh, I had forgotten about that! Thanks!

        Question – About Surface Mesh

        After I tried to improve surface mesh,  I always been getting this license issue.

         

        About Volume mesh

        Tried with poly-hexcore, this error message appeared:

         

         

         

        Error: Exiting due to license issue
        Cannot grow prisms.
        Mesh object "...solid-body-half-model-test" has no valid Scoped Prisms.
        Auto mesh failed.

         

         

         

        Tried with polyhedra:

        After the failed mesh, Fluent won't let me retry Volume mesh again.

        I achieved max skewness of 0.79 prior after improving surface mesh (which is by best so far, as 0.95 seems to be my current best surface mesh (without mesh improvement/or failed improved mesh), of those two volume meshes.

        Is it due to my student license?
        My uni’s FSAE team just as of last week got sponsored by Ansys! Will that version of Ansys Fluent unlock more meshing power or solve my error issues?

         

        Thanks again! :)

         

         

         

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