{"id":34195,"date":"2019-03-25T14:43:14","date_gmt":"2019-03-25T14:43:14","guid":{"rendered":"\/forum\/forums\/topic\/system-coupling-rms-convergence-criteria\/"},"modified":"2019-03-25T14:43:14","modified_gmt":"2019-03-25T14:43:14","slug":"system-coupling-rms-convergence-criteria","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/system-coupling-rms-convergence-criteria\/","title":{"rendered":"System coupling RMS convergence criteria"},"content":{"rendered":"<p>Dear reader,<\/p>\n<p><\/p>\n<p>I am simulating a blood vessel in using system coupling between Fluent and tMechanical for two-way FSI coupling.<br \/>During my simulation interface forces and displacements match perfectly after the chosen coupling iterations. In the contrary the RMS used for determening if a system coupling step is stable\/converged is not reaching it&#8217;s limit. After plotting the seperate components of the force transfer and displacement transfer i came to the conclusion that both sides produced a stable and matching solution (figures below). But i saw some kind of cyclic behaviour between the x and y components. The z-component was overal fairly stable during the coupling step.<\/p>\n<p><\/p>\n<p>Therefore my question: What causes this cyclic behaviour (it seems as a common problem)&nbsp;or is there fix\/mistake to this model?<\/p>\n<p><\/p>\n<p>Furthermore since the forces and displacements on the interface match and the behaviour is kind of cyclical could i conclude that the RMS is not a suitable measure for convergence of a coupling step in my model?<\/p>\n<p>Thank you for your advice.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/a7d9e2ef-7fc3-4cdf-96e3-a90300aec483\/5fe7f9b0-5448-46fe-90f0-aa1b00f154a0_forcex.jpg?width=690&amp;upscale=false\" alt=\"force transfer x\"><\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/a7d9e2ef-7fc3-4cdf-96e3-a90300aec483\/4dd664a8-d4dd-413f-a700-aa1b00f16827_forcey.jpg?width=690&amp;upscale=false\" alt=\"force transfer y\"><\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/a7d9e2ef-7fc3-4cdf-96e3-a90300aec483\/b8ea2226-5491-44c0-ad07-aa1b00f17ad4_force-z.jpg?width=690&amp;upscale=false\" alt=\"force transfer z\"><\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/a7d9e2ef-7fc3-4cdf-96e3-a90300aec483\/60626222-af68-429a-a198-aa1b00f2376a_dx.jpg?width=690&amp;upscale=false\" alt=\"\"><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/a7d9e2ef-7fc3-4cdf-96e3-a90300aec483\/cf1f6a65-bead-4945-804a-aa1b00f23f6c_dy.jpg?width=690&amp;upscale=false\" alt=\"\"><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/a7d9e2ef-7fc3-4cdf-96e3-a90300aec483\/af12e75b-fa0c-4ec8-830c-aa1b00f247b1_dz.jpg?width=690&amp;upscale=false\" alt=\"\"><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/a7d9e2ef-7fc3-4cdf-96e3-a90300aec483\/0aa29f0e-382e-4c02-b251-aa1b00f2755f_rms.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n","protected":false},"template":"","class_list":["post-34195","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["6367"],"_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","0"],"_btv_view_count":["831"],"_bbp_subscription":["236345"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["34195"],"_bbp_forum_id":["27792"],"_bbp_engagement":["157321","184521"],"_bbp_voice_count":["2"],"_bbp_reply_count":["1"],"_bbp_last_reply_id":["138185"],"_bbp_last_active_id":["138185"],"_bbp_last_active_time":["2021-01-08 23:52:18"]},"test":"jurjen"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/34195","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\/34195\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=34195"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}