{"id":41833,"date":"2020-03-16T15:44:19","date_gmt":"2020-03-16T15:44:19","guid":{"rendered":"\/forum\/forums\/topic\/cfl-number-in-eulerian-multiphase-flow\/"},"modified":"2020-03-16T15:44:19","modified_gmt":"2020-03-16T15:44:19","slug":"cfl-number-in-eulerian-multiphase-flow","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/cfl-number-in-eulerian-multiphase-flow\/","title":{"rendered":"CFL Number in Eulerian Multiphase Flow"},"content":{"rendered":"<p>Hi all,<\/p>\n<p><\/p>\n<p>I am calculating an instationous water-air two-phase-flow with the eulerian-multi-phase model. The Volume Fraction Formulation is explicit and the time stepping method is calculated variable with a global Courant Number (CFL) of 1. While fluent is calculating the solution i can read in the Console: &#8220;Global Courant Number [variable Time Step Criteria]&#8221; (with the value of 1) and &#8220;Global Courant Number [Explicit VOF Criteria]&#8221; (with a value around 0.4). What is the difference between theses two CFL-Numbers?<\/p>\n<p><\/p>\n<p>Moreover I have read in the Fluent User-Guide that it is recommended to choose the CFL-Number as 2 and I am wondering if the Solution is even physical? I thought we need for a accurate time discetisation a cfl number equal or less than one?<\/p>\n<p><\/p>\n<p>Thank you so much for your help!<\/p>\n","protected":false},"template":"","class_list":["post-41833","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["14013"],"_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":["1555"],"_bbp_subscription":["248621"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["41833"],"_bbp_forum_id":["27792"],"_bbp_engagement":["22555","174401"],"_bbp_voice_count":["2"],"_bbp_reply_count":["3"],"_bbp_last_reply_id":["108050"],"_bbp_last_active_id":["108050"],"_bbp_last_active_time":["2020-03-17 13:17:07"]},"test":"fs2020"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/41833","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\/41833\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=41833"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}