{"id":372749,"date":"2024-07-19T13:26:08","date_gmt":"2024-07-19T13:26:08","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/suddenly-divergence-in-transient-simulation-with-vof\/"},"modified":"2024-07-19T13:26:08","modified_gmt":"2024-07-19T13:26:08","slug":"suddenly-divergence-in-transient-simulation-with-vof","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/suddenly-divergence-in-transient-simulation-with-vof\/","title":{"rendered":"Suddenly divergence in transient simulation with VOF"},"content":{"rendered":"<p>Hi,<\/p>\n<p>I have model below and simulating natural convection. Two phases, namely water-liquid and water-vapor, are considered. The lower piper on the right is heating wall. At initial condition, whole pipe was filled with water except that upper half of water tank was filled with water-vapor. Water was heated and would boil in rising section because saturation temperature decrease with decreasing water pressure. Therefore, a natural circulation is formed.&nbsp;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/07\/19-07-2024-1721393793-mceclip5.png\" width=\"249\" height=\"246\"><\/p>\n<p>In the case, saturation temperature used in Lee model is specified as pressure dependent. At initial few seconds, all seems run well. But residual suddenly ascended and diverged.&nbsp; Fluent console shown turbulent viscosity turbulent viscosity limited to viscosity ratio of 1.000000e+05 and limited temperature of 5K.&nbsp;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/07\/19-07-2024-1721394000-mceclip6.png\" width=\"250\" height=\"161\"><\/p>\n<p>It&#8217;s temperature before divergence. The strange situation keep exsiting with increasing flow time. The vapor in upper tank will be affected by heated water due to decreasing density and boiling. Therefore adverse flow warning keep existing during simulation. But the high temperature is unanticipated. I don&#8217;t know if solution diverged because of vapor temperature in upper tank.&nbsp;<\/p>\n<p>What&#8217;s happending during simulation?&nbsp; Any suggestions given is highly appreciated!!<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/07\/19-07-2024-1721394670-mceclip10.png\"><\/p>\n","protected":false},"template":"","class_list":["post-372749","topic","type-topic","status-closed","hentry","topic-tag-fluent","topic-tag-ImplicitVOF-1","topic-tag-natural-convection"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["51510","199"],"_bbp_author_ip":["2001:250:3002:3270:7f84:d980:f12:d1e5"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_bbp_likes_count":["1"],"_btv_view_count":["583"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["372749"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","51510"],"_bbp_voice_count":["2"],"_bbp_reply_count":["6"],"_bbp_last_reply_id":["373173"],"_bbp_last_active_id":["373173"],"_bbp_last_active_time":["2024-07-23 08:26:50"]},"test":"bfdef4e41fe840e99014e0c0ef18055b3cd7380f"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/372749","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\/372749\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=372749"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}