{"id":397059,"date":"2024-12-11T09:34:24","date_gmt":"2024-12-11T09:34:24","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/generating-non-conformal-mesh-for-sliding-mesh-when-moving-domain-is-a-sphere\/"},"modified":"2024-12-12T10:14:51","modified_gmt":"2024-12-12T10:14:51","slug":"generating-non-conformal-mesh-for-sliding-mesh-when-moving-domain-is-a-sphere","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/generating-non-conformal-mesh-for-sliding-mesh-when-moving-domain-is-a-sphere\/","title":{"rendered":"Generating non-conformal mesh for sliding mesh when moving domain is a sphere"},"content":{"rendered":"

<p>Hi, I am trying to perform an external flow analysis of a rocket. To find the damping, I need to run transient pitching and rolling simulations. I am using a sliding mesh approach. However, I cannot get Ansys fluent meshing to detect the face zones properly and create a non-conformal mesh, specifically when the moving domain is a sphere. Everything works correctly when the moving domain is a cylinder.<\/p><p>My method for generating the geometry consists of the following:<\/p><\/p>\n

    \n
  1. Use create enclosure on rocket body to create spherical or cylindrical moving domain.<\/li>\n
  2. Move the solid out of the enclosure component and rename to movingDomain and delete the empty component.<\/li>\n
  3. Use create enclosure on ‘movingDomain’ solid to create staticDomain.<\/li>\n
  4. Move the solid out of the enclosure component and rename to ‘staticDomain’ and delete the empty component.<\/li>\n
  5. Delete\/hide and suppress the original rocket body<\/li>\n
  6. Create named selections:\n
      \n
    1. Outside faces: ‘far-field’<\/li>\n
    2. ‘staticDomain’ inner face(s): ‘interface-static’<\/li>\n
    3. ‘movingDomain’ outer face(s): ‘interface-moving’<\/li>\n
    4. ‘movingDomain’ object faces: ‘wall-xxx’<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n

      <p>Below are the results of this process when using a sphere as the internal sliding mesh interface or a cylinder as the interface.<\/p><p><\/p><p><\/p><p><\/p><\/p>\n

        \n
      1. Next I use the workbench->fluent 2024 R2->watertight workflow button to move to fluent meshing.<\/li>\n
      2. The difference between the two cases appears when running the ‘generate the surface mesh’ task. \n
          \n
        1. For the sphere case, a new face zone is auto-created called far-field:xxxx, and no ‘generate non-conformal mesh’ option is available under describe geometry task<\/li>\n
        2. This far-field:xxxx face zone remains throughout the rest of the process and then causes issues when switching to solution mode as far-field:xxx face zone is the same as the ‘interface-static’ zone. Basically, somehow, an extra face or face selection is created on the sliding mesh interface. Which results in an extra boundary.<\/li>\n
        3. This also happens when selecting the share topology option in fluent meshing OR selecting share topology in SpaceClaim or Discovery before importing. (I tried this even though I need a non-conformal mesh for the sliding mesh analysis)<\/li>\n
        4. <\/li>\n<\/ol>\n<\/li>\n
        5. When clicking generate surface mesh task in the cylinder case:\n
            \n
          1. This works as intended: No new ‘fair-field:xxx’ face zone is created.<\/li>\n
          2. Non-conformal mesh between objects is available in describe geometry<\/li>\n
          3. Finishing meshing and switching to solution mode shows that all the boundaries are generated properly and that a sliding mesh analysis can be run.<\/li>\n
          4. <\/li>\n<\/ol>\n<\/li>\n<\/ol>\n

            <p>If anyone has an idea why there might be a difference between these two cases, please let me know. It seems like a bug or error to me. The only difference I can think of is that in the case of the cylinder interface, there are a number of edges present, while in the case of the sphere, there are no edges. While waiting for a reply, I will try imprinting an edge on the sphere to see if that changes the results. <\/p><p>Using a sphere as an interface is rather important for me as I need to be able to rotate the inner sphere in arbitrary directions. Generating a new mesh with a cylinder perfectly matching each angle would be basically impossible. <\/p><p>Please note that I have also tried several different ways of generating the same input geometry. For example, I created the whole enclosure and sphere and then used the combine tool, or I manually created every solid.  Either way, the results are the same.<\/p><\/p>\n","protected":false},"template":"","class_list":["post-397059","topic","type-topic","status-closed","hentry","topic-tag-ansys-fluent-meshing-1","topic-tag-cad-import","topic-tag-cell-zone","topic-tag-sliding-mesh","topic-tag-sphere"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27796"],"_bbp_topic_id":["397059"],"_bbp_subscription":["458034","199"],"_bbp_author_ip":["145.94.147.76"],"_bbp_last_reply_id":["397227"],"_bbp_last_active_id":["397227"],"_bbp_last_active_time":["2024-12-12 10:14:43"],"_bbp_reply_count":["1"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["2"],"_bbp_engagement":["458034","199"],"_btv_view_count":["392"],"_bbp_topic_status":["unanswered"],"_bbp_likes_count":["1"],"_bbp_notification_enabled":["458034"],"_bbp_status":["publish"]},"test":"24536951c2fe7299be98f49975278ee5bfbc813e"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/397059","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/397059\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=397059"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}