{"id":374790,"date":"2024-08-01T22:13:50","date_gmt":"2024-08-01T22:13:50","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/adaptive-time-step-for-fluent-in-structural-fluent-system-coupling-simulation\/"},"modified":"2024-08-01T22:13:50","modified_gmt":"2024-08-01T22:13:50","slug":"adaptive-time-step-for-fluent-in-structural-fluent-system-coupling-simulation","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/adaptive-time-step-for-fluent-in-structural-fluent-system-coupling-simulation\/","title":{"rendered":"Adaptive time step for fluent in structural &#8211; fluent system coupling simulation"},"content":{"rendered":"<p>Hi,<\/p>\n<p>I am doing a system coupling simulation with Transient Structural and Fluent. I always use the fixed time stepping for system coupling (for example, dt = 0.001). Therefore, the system coupling setting overrides both mechanical and fluent settings.&nbsp;<\/p>\n<p>I often met cases where fluent met negative cell volume, where I needed to decrease dt in system coupling (dt_sc) thereby fluent dt to resolve. I already tried finer mesh resolution in interested region but negative cell volume may happen once FSI interface undergoes quick deformation.&nbsp;<\/p>\n<p>However, in simulation with fixed dt for system coupling, the mechanical solver can adaptively integrate with smaller dt till dt_sc in system coupling is reached, while fluent can only do dt_fluent = dt_sc. I noticed Fluent has an adaptive time stepping option, but my trial always results in a mismatch between fluent time and system coupling time.&nbsp;<\/p>\n<p>Can you tell me if I can do a fixed dt for system coupling, while fluent can do an adaptive dt to avoid negative cell volume issues?<\/p>\n<p>Thank you!<\/p>\n<p>Eric<\/p>\n","protected":false},"template":"","class_list":["post-374790","topic","type-topic","status-publish","hentry","topic-tag-2-way-coupled-fsi","topic-tag-autotimestepping-1","topic-tag-fluent","topic-tag-systemcoupling","topic-tag-transient-structural"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["21343","199"],"_bbp_author_ip":["2607:ea00:117::b6"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["314"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["374790"],"_bbp_forum_id":["27796"],"_bbp_engagement":["199","21343"],"_bbp_voice_count":["2"],"_bbp_reply_count":["4"],"_bbp_last_reply_id":["379241"],"_bbp_last_active_id":["379241"],"_bbp_last_active_time":["2024-08-16 05:41:21"]},"test":"yu272umn-edu"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/374790","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\/374790\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=374790"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}