{"id":165232,"date":"2022-01-03T14:13:44","date_gmt":"2022-01-03T14:13:44","guid":{"rendered":"\/forum\/forums\/topic\/time-step-selection-after-convergence\/"},"modified":"2022-01-04T14:09:53","modified_gmt":"2022-01-04T14:09:53","slug":"time-step-selection-after-convergence","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/time-step-selection-after-convergence\/","title":{"rendered":"time step selection after convergence"},"content":{"rendered":"
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Hi,<\/p>\n

I am running transient simulation and implicit formulation of vof model. I have selected adaptive time advancement method. I set the global courant number as 0.5,initail time step size 0.00001 s , number of time step 10,000 , max iteration 60. when i run , it says , 230 solution has been converged in fourth time step . I have been running my simulation since yesterday and its progressing very very slowly and its only 3 % in 8 hrs. My questions are:<\/p>\n

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  1. once its says after some iteration like it says 230 solutions has been converged, what is the meaning of physical time step in range of 10^-4 in between the iteration and also what is the meaning of global courant number 0.1 while running simulation in console ? <\/li>\n
  2. Based on what and after which time we will know that we can increase the initial time step size which in my case is set to 0.00001. I want to increase the time step size because it will take too long time for complete simulation and I have very limited time.<\/li>\n
  3. Once the solution has reached convergence ,can we also decrease number of iteration ? (Suggestion with explanation on this please)<\/li>\n
  4. Is it based on the courant number and the physical time step , we can increase the initial time step?<\/li>\n
  5. Also , what is the reason behind not getting very low value of residual for continuity ?<\/li>\n<\/ol>\n

    Thank You in advance.<\/p>\n","protected":false},"template":"","class_list":["post-165232","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_author_ip":[""],"_bbp_old_reply_author_name_id":["Anonymous"],"_bbp_old_is_reply_anonymous_id":["false"],"_btv_view_count":["1204"],"_bbp_likes_count":["0"],"_bbp_subscription":["242444"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["165232"],"_bbp_forum_id":["27792"],"_bbp_engagement":["25","242444"],"_bbp_voice_count":["2"],"_bbp_reply_count":["1"],"_bbp_last_reply_id":["201691"],"_bbp_last_active_id":["201691"],"_bbp_last_active_time":["2022-01-04 14:09:53"]},"test":"spo001un-ihe-org"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/165232","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\/165232\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=165232"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}