{"id":44171,"date":"2020-05-19T19:27:20","date_gmt":"2020-05-19T19:27:20","guid":{"rendered":"\/forum\/forums\/topic\/getting-a-plug-flow-when-implementing-a-parabolic-velocity-profile-udf-in-a-3d-pipe\/"},"modified":"2020-05-19T19:27:20","modified_gmt":"2020-05-19T19:27:20","slug":"getting-a-plug-flow-when-implementing-a-parabolic-velocity-profile-udf-in-a-3d-pipe","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/getting-a-plug-flow-when-implementing-a-parabolic-velocity-profile-udf-in-a-3d-pipe\/","title":{"rendered":"getting a plug flow when implementing a parabolic velocity profile UDF in a 3D pipe"},"content":{"rendered":"<p>Hi everyone,<\/p>\n<p><\/p>\n<p>I&#8217;m trying to implement a parabolic velocity profile at the inlet of a 3D pipe (for a steady flow case), the inlet itself is not perpendicular to any of the primary axes.<\/p>\n<p><\/p>\n<p>I used the following UDF:<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/b5917bdf-62e6-4146-9fd7-abc00133c67d\/4de1a4d3-59a8-4109-9c89-abc0013ae963_capture.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n<p><\/p>\n<p>After running the simulation,&nbsp;the result was a plug flow at the inlet of 7.07[m\/s] as I implemented instead of parabolic profile. Furthermore, changing the radius units to [m]&nbsp;led to non-converged solution.&nbsp;I also tried implementing the UDF as a velocity magnitude (which gave a plug flow that developed to parabolic at the outlet) and as an axial velocity in cylindrical coordinates (gave reversed flow for all iterations).&nbsp;<\/p>\n<p><\/p>\n<p>I&#8217;ve tried other manipulations but nothing worked.<\/p>\n<p><\/p>\n<p>Finally, the easiest way to deal with this situation is to elongate the pipe and insert a constant velocity, then get the profile to develop, but in this case, the profile I get is not precise enough, Not to mention that it takes additional computational time which I&#8217;m trying to avoid due the complex geometry.&nbsp;<\/p>\n<p><\/p>\n<p>I&#8217;d appreciate your help,<\/p>\n<p><\/p>\n<p>Thanks,<\/p>\n","protected":false},"template":"","class_list":["post-44171","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["16352"],"_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":["969"],"_bbp_subscription":["251569","288658","199"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["44171"],"_bbp_forum_id":["27792"],"_bbp_engagement":["59","199","177418","288658"],"_bbp_voice_count":["4"],"_bbp_reply_count":["9"],"_bbp_last_reply_id":["292327"],"_bbp_last_active_id":["292327"],"_bbp_last_active_time":["2023-07-10 13:59:53"]},"test":"leen"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/44171","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\/44171\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=44171"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}