{"id":343833,"date":"2024-01-10T08:46:45","date_gmt":"2024-01-10T08:46:45","guid":{"rendered":"\/forum\/?post_type=topic&#038;p=343833"},"modified":"2024-01-10T08:46:45","modified_gmt":"2024-01-10T08:46:45","slug":"external-gear-pump-analysis-w-udf-negative-cell-volume","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/external-gear-pump-analysis-w-udf-negative-cell-volume\/","title":{"rendered":"External Gear Pump Analysis w\/ UDF (Negative Cell Volume)"},"content":{"rendered":"<p>Hello<\/p>\n<p>I&#8217;m working on 3D gear pump analysis. In the original model, two gears rotate by contacting each other, but since it will be easir to understand dynamic mesh logic, I reduce the model to a single gear and add it here.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/01\/09-01-2024-1704814095-mceclip0.png\" width=\"1259\" height=\"708\"><\/p>\n<p>&nbsp;<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/01\/09-01-2024-1704814197-mceclip2.png\"><\/p>\n<p>&nbsp;<\/p>\n<p>I wrote a simple udf for the analysis model and named the inner surface of the gear. Then I turned on smoothing and remeshing for dynamic mesh, and defined rotational motion for the inner surface of the gear. I see the movement of the walls via Zone Motion without getting any problem, but when I run the analysis I get negative cell volume error. Also I get this error when trying to see mesh motion. I tried reducing the time step size and add dynamic mesh deformation to the side surface of gear, but no matter how much I reduced it or add deformation to the walls, the problem was not solved. In addition, after each error, the meshes appear to be corrupted as follows.<\/p>\n<p>&nbsp;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/01\/09-01-2024-1704814158-mceclip1.png\" width=\"1059\" height=\"596\"><\/p>\n<p><span style=\"font-size: 14pt\">Can someone show me where I make mistake or help me understand how I can perform this 3D gear pump analysis with UDF?<\/span><\/p>\n","protected":false},"template":"","class_list":["post-343833","topic","type-topic","status-closed","hentry","topic-tag-externalgearpump-1","topic-tag-udf"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_author_ip":["96.7.74.173"],"_bbp_subscription":["292772","13659"],"_wp_old_date":["2024-01-09"],"_btv_view_count":["675"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["343833"],"_bbp_forum_id":["27792"],"_bbp_engagement":["13659","292772"],"_bbp_voice_count":["2"],"_bbp_reply_count":["4"],"_bbp_last_reply_id":["344716"],"_bbp_last_active_id":["344716"],"_bbp_last_active_time":["2024-01-15 12:47:12"]},"test":"akndnzmngmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/343833","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":1,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/343833\/revisions"}],"predecessor-version":[{"id":343943,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/343833\/revisions\/343943"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=343833"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}