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Topics relate to geometry, meshing, and CAD

How to generate prism elements through extrusion on complex surfaces?

    • nkulkar2
      Subscriber

      I have a complex geometry consisting subchannels and grid walls and I want to add prism layers on these walls to capture the near wall effects. I have tried using the prism generation after tet-mesh generation but it always results in generation of pyramid elements and my finals mesh has to be only tets and prisms.

      Before this I have used mesh extrusion to create boundary layers but that was for singular surfaces. In the present geometry the surfaces are very complex and often meet each other at different angles so I don't know how well this method will work.

      Is there a way to mesh this geometry? I have attached the screenshots below. The pink part is the grid wall (which has a lot of indents and sharp corners) and the red part has solid cylindrical rods. Both these parts need prism layers. The green lines surrounding them is the fluid domain around these parts.


    • Keyur Kanade
      Ansys Employee
      You can create prisms in ICEM. This would require defining surface mesh size and correct prism controls. nJust looking at one image it is difficult to tell what modifications are required. So first please check if you have defined correct surface mesh sizes and get good quality tet mesh. Next you will have to define correct prsim parameters. Make sure that prism ends at appropriate faces to avoid any quad surface mesh elements. nYou also mentioned that you have sharp corners. It is recommended that you remove those sharp corners in SpaceClaim before proceeding to mesh. Also consider meshing it in Ansys Meshing if you are using tet plus prism. nPlease go through help manual for more details nRegards,nKeyurnHow to access Ansys Online Help DocumentnHow to show full resolution imagenGuidelines on the Student CommunitynHow to use Google to search within Ansys Student Communityn
    • nkulkar2
      Subscriber
      Hi Keyur,nI made changes in Advanced prism meshing parameters by turning off refine boundary and stop column and turning on auto reduction. And by the sharp corners I meant there are a lot of faces that meet at 90 degrees and creates a lot of tight areas where the edge length needs to be small (~0.5-0.7mm) to capture the geometry accurately. These are the areas which need the prism layers. nI have not yet tried to refine the tet mesh as much. Is there a specific quality metric that I need to check, and below what value are the pyramids formed? n
    • Keyur Kanade
      Ansys Employee
      Please check orthogonal quality. I would suggest you take only small portion of the geometry. Then test with all parameters with prisms etc. Then apply that strategy to full model. nRegards,nKeyurnHow to access Ansys Online Help DocumentnHow to show full resolution imagenGuidelines on the Student CommunitynHow to use Google to search within Ansys Student Communityn
    • nkulkar2
      Subscriber
      I did mesh individual sections and I can get a mesh without pyramids. But when clubbed together I get pyramids.nI will look out for the orthogonal quality.n
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