{"id":40327,"date":"2020-01-22T17:46:05","date_gmt":"2020-01-22T17:46:05","guid":{"rendered":"\/forum\/forums\/topic\/gap-occurs-in-velocity-in-stn-frame-contour-fluent-3d-transient-mesh-motion\/"},"modified":"2020-01-22T17:46:05","modified_gmt":"2020-01-22T17:46:05","slug":"gap-occurs-in-velocity-in-stn-frame-contour-fluent-3d-transient-mesh-motion","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/gap-occurs-in-velocity-in-stn-frame-contour-fluent-3d-transient-mesh-motion\/","title":{"rendered":"Gap occurs in Velocity in Stn Frame contour – Fluent 3D, Transient, Mesh motion"},"content":{"rendered":"

Greetings!<\/p>\n

<\/p>\n

I am facing an issue when simulating a rotating fluid body within a fluid channel body. Here is a description of the situation and problem; along with an attached image and my questions.<\/p>\n

<\/p>\n

Situation:<\/strong><\/h3>\n

<\/p>\n

A 3D, Transient simulation involving 2 bodies was setup in FLUENT, as shown in attached image.<\/p>\n

<\/p>\n

In ‘DesignModeler’, a 3D bluff body was drawn. A sphere ‘enclosure’ was made around the bluff body, and the bluff body was removed (deleted\/suppressed). Then, a box ‘enclosure’ was made around this sphere. Both bodies were set to ‘Fluid’ condition. In ‘Meshing’, the default meshing conditions was taken; and mesh generated.<\/p>\n

<\/p>\n

In Setup, ‘Transient’ mode was selected. ‘Air’ is the material given. In ‘Setup>Cell Zone Conditions’, the sphere was made rotating with ‘mesh motion’ selected, with a rotational speed of 2 rad\/s. In ‘Boundary Conditions’, inlet velocity was given as 25 m\/s. Outer walls was given a specified shear value of 0 units. Outlet is ‘pressure outlet’. The inner walls of the bluff body shape is made ‘rotating wall’ with no rotational velocity specified.<\/p>\n

<\/p>\n

In ‘Solution’ section, ‘initialisation’ was done & simulation done for a time step of 0.001 second, for 1000 time steps, and 6 iterations\/time step.<\/p>\n

<\/p>\n

Problem:<\/h3>\n

<\/p>\n

A separate ‘Results’ component was pulled in, and the ‘.cdat’ results loaded. I created a plane along XY axis, and plotted the contour of “Velocity in Stn Frame’. The result is shown in the attached image. A gap occurs in the flow domain, which is unintended.<\/p>\n

<\/p>\n

Questions:<\/h3>\n

<\/p>\n

    <\/p>\n
  • Could you tell me why it occurs? <\/li>\n

    <\/p>\n

  • Will the simulation be accurate, even if I get that gap?<\/li>\n

    <\/p>\n

  • Any way to close that gap? Or, how to prevent it from occuring?<\/li>\n

    \n<\/ul>\n

    <\/p>\n

     <\/p>\n

    <\/p>\n

    If you can help me, please help me. Should you need additional info, please reply. Thanks in advance, for your time and help.<\/p>\n

    <\/p>\n

      <\/p>\n
    • Regards,<\/em><\/li>\n

      <\/p>\n

    • A Paul<\/em><\/li>\n

      <\/p>\n

    • (Post graduate student, Aerospace Engg)<\/em><\/li>\n

      \n<\/ul>\n

      <\/p>\n

      #EDIT_IN_ORIGINAL_POST<\/em><\/p>\n

      <\/p>\n

      Picture:<\/h3>\n

      <\/p>\n

      \"\"\"A<\/p>\n","protected":false},"template":"","class_list":["post-40327","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["12507"],"_bbp_old_topic_author_name_id":["Anonymous"],"_bbp_old_is_topic_anonymous_id":["false"],"_bbp_old_closed_status_id":["publish"],"_bbp_author_ip":[null],"_bbp_old_sticky_status_id":["normal"],"_bbp_likes_count":["0"],"_btv_view_count":["837"],"_bbp_subscription":["246756"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["40327"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","172469"],"_bbp_voice_count":["2"],"_bbp_reply_count":["4"],"_bbp_last_reply_id":["103467"],"_bbp_last_active_id":["103467"],"_bbp_last_active_time":["2020-01-26 09:17:55"]},"test":"apaul"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/40327","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\/40327\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=40327"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}