{"id":369428,"date":"2024-05-31T15:38:50","date_gmt":"2024-05-31T15:38:50","guid":{"rendered":"\/forum\/forums\/topic\/vof-experiencing-convergence-difficulties\/"},"modified":"2024-05-31T15:38:50","modified_gmt":"2024-05-31T15:38:50","slug":"vof-experiencing-convergence-difficulties","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/vof-experiencing-convergence-difficulties\/","title":{"rendered":"VOF &#8211; Experiencing convergence difficulties"},"content":{"rendered":"<p>Hello together<\/p>\n<p>I am trying to simulate a liquid free jet in a gas. &nbsp;The goal is to model the amplitude of the free surface. In real test the phenomenon is stationary.<\/p>\n<p>In the following principle sketch my boundary conditions are shown.<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/05\/31-05-2024-1717169301-mceclip0.png\"><\/p>\n<p>I use an ICEM CFD mesh with 12 million cells. The quality of the mesh is as follows:<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/05\/31-05-2024-1717169352-mceclip1.png\"><\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/05\/31-05-2024-1717169465-mceclip2.png\"><\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/05\/31-05-2024-1717169496-mceclip3.png\"><\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/05\/31-05-2024-1717169532-mceclip4.png\"><\/p>\n<p>I calculate with the following settings:<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/05\/31-05-2024-1717169562-mceclip5.png\"><\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/05\/31-05-2024-1717169582-mceclip6.png\"><\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/05\/31-05-2024-1717169896-mceclip12.png\"><\/p>\n<p>The residuals look like this:<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/05\/31-05-2024-1717169623-mceclip7.png\"><\/p>\n<p>The monitor of the mass flow at the outlet looks like this:<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/05\/31-05-2024-1717169651-mceclip8.png\"><\/p>\n<p>Monitor points with the pigginess look like this:<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/05\/31-05-2024-1717169672-mceclip9.png\"><br \/>I always get the following message:<\/p>\n<p>&#8220;Experiencing convergence difficulties &#8211; temporarily relaxing and trying again&#8230;&#8221;<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/05\/31-05-2024-1717169695-mceclip10.png\"><\/p>\n<p>What could be the reason for this message? The simulation takes an extremely long time for one iteration.<br \/>Is it possibly due to the mesh?<br \/>Are there ways to speed up the convergence?&nbsp;<br \/>If I compare the inlet and outlet I get this:&nbsp;<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/05\/31-05-2024-1717169809-mceclip11.png\"><br \/>Why is the residual of the mass balance still so bad?<\/p>\n<p>Thank you very much<br \/>Greetings<\/p>\n","protected":false},"template":"","class_list":["post-369428","topic","type-topic","status-closed","hentry","topic-tag-twophase","topic-tag-vof"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["341799","199"],"_bbp_author_ip":["184.24.96.177"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["541"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["369428"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","341799"],"_bbp_voice_count":["2"],"_bbp_reply_count":["1"],"_bbp_last_reply_id":["369571"],"_bbp_last_active_id":["369571"],"_bbp_last_active_time":["2024-06-03 12:48:11"]},"test":"claudedavid-spirgifhnw-ch"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/369428","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\/369428\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=369428"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}