{"id":163963,"date":"2021-11-15T04:07:16","date_gmt":"2021-11-15T04:07:16","guid":{"rendered":"\/forum\/forums\/topic\/oscillating-residuals-after-creating-finer-mesh-or-is-this-the-solution\/"},"modified":"2021-11-16T11:27:00","modified_gmt":"2021-11-16T11:27:00","slug":"oscillating-residuals-after-creating-finer-mesh-or-is-this-the-solution","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/oscillating-residuals-after-creating-finer-mesh-or-is-this-the-solution\/","title":{"rendered":"Oscillating residuals after creating finer mesh &#8211; or is this the solution?"},"content":{"rendered":"<div class=\"Item-Body\">\n<div class=\"Message userContent\">\n<p>Hello, new fluent user here. One of my course assignments was to model the flow around a NACA 0015 at 12 degrees aoa in fluent, using three different c grid meshes, with both inviscid and viscid (transition k-kl omega) using the density based solver. The coarsest mesh worked just fine for both viscid and inviscid. I then reduced the average cell size by around 1.5, and inviscid worked fine. When I tried to run the viscid, the residuals got stuck in this cycle and would not go down. I tried messing with the courant number (currently set at 5), and tried anything from 0.5 to 50. No dice. I am trying to get the continuity residual below 1e-5.<\/p>\n<p>I tried lowering the URF&#039;s for the k, kl, and omega, but that did not help either. I can&#039;t seem to find an answer from anywhere online, as most have oscillations, but they change in magnitude, and here, they are exactly the same for 10000+ iterations. I also heard that these oscillations could be indicating convergence of the solution, but when I look at the generated force coefficients, they are steadily increasing with more iterations, so I am not sure if it is really converged here. I attached a picture of the residuals here, hoping someone can help me out. Thanks!<\/p>\n<div class=\"embedExternal embedImage\">\n<div class=\"embedExternal-content\">\n<a class=\"embedImage-link\" href=\"\/forum\/wp-content\/uploads\/forum-uploads\/339\/ELF7V42MYWIW.png\" rel=\"nofollow noopener\" target=\"_blank\"><br \/>\n<img decoding=\"async\" class=\"embedImage-img\" src=\"\/forum\/wp-content\/uploads\/forum-uploads\/339\/ELF7V42MYWIW.png\" alt=\"image (1).png\" \/><br \/>\n<\/a><\/p>\n","protected":false},"template":"","class_list":["post-163963","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":["3521"],"_bbp_likes_count":["0"],"_bbp_subscription":["240568"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["163963"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","240568"],"_bbp_voice_count":["2"],"_bbp_reply_count":["3"],"_bbp_last_reply_id":["197702"],"_bbp_last_active_id":["197702"],"_bbp_last_active_time":["2021-11-16 11:27:00"]},"test":"aloshadavydenkohotmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/163963","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\/163963\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=163963"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}