{"id":292617,"date":"2023-07-11T22:38:42","date_gmt":"2023-07-11T22:38:42","guid":{"rendered":"\/forum\/forums\/topic\/negative-cell-volume-occuring-when-using-a-quarter-model\/"},"modified":"2023-07-11T22:38:42","modified_gmt":"2023-07-11T22:38:42","slug":"negative-cell-volume-occuring-when-using-a-quarter-model","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/negative-cell-volume-occuring-when-using-a-quarter-model\/","title":{"rendered":"Negative cell volume occuring when using a quarter model"},"content":{"rendered":"<p>Dear fluent users,<\/p>\n<p>I have an entire model running well. Based on the reference paper, i need to mesh the model with mesh size of 10 &micro;m which means more than 50 000 000 elements. I reduced the model to a quarter to save computational time but i have negative cell volume occuring during the simulation. I tried solutions provide on research gate for the same issue&nbsp; :<\/p>\n<p>&#8211; try PISO method<\/p>\n<p>&#8211; Timesteps less than 0.005<\/p>\n<p>&#8211; reduce the relaxation energy value from 1.0 to 0.6<\/p>\n<p>but the issue still occurs.<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/07\/11-07-2023-1689115020-mceclip1.png\"><\/p>\n<p>The quarter model<br \/><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/07\/11-07-2023-1689114182-mceclip0.png\"><\/p>\n<p>I&#8217;m trying to simulate a wall moving normal to a stationary wall with an amplitude ratio of 0.8 of the initial air gap (200&micro;m)<br \/>Mesh elements are tetrahedrals, mesh size 100 &micro;m<br \/>Dynamic mesh is set to layering and unified remeshing, cell height 20 &micro;m<br \/>The model is laminar with air &#8211; ideal gas<br \/>Time step size =&nbsp; 5e-5 s<\/p>\n","protected":false},"template":"","class_list":["post-292617","topic","type-topic","status-closed","hentry","topic-tag-moving-deforming-mesh-2","topic-tag-negative-cell-volume"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["237303","18096"],"_bbp_author_ip":["23.33.28.199"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["615"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["292617"],"_bbp_forum_id":["27792"],"_bbp_engagement":["18096","237303"],"_bbp_voice_count":["2"],"_bbp_reply_count":["5"],"_bbp_last_reply_id":["295335"],"_bbp_last_active_id":["295335"],"_bbp_last_active_time":["2023-07-28 10:13:59"]},"test":"loic-macaire-sidjou-nzali-1ens-etsmtl-ca"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/292617","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\/292617\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=292617"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}