{"id":398209,"date":"2024-12-22T13:22:51","date_gmt":"2024-12-22T13:22:51","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/udf-compiles-the-air-equation-of-state\/"},"modified":"2024-12-22T13:22:51","modified_gmt":"2024-12-22T13:22:51","slug":"udf-compiles-the-air-equation-of-state","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/udf-compiles-the-air-equation-of-state\/","title":{"rendered":"udf compiles the air equation of state"},"content":{"rendered":"<p>&lt;p&gt;I am using VOF to calculate two-phase flow and I need to simulate a situation where there is negative pressure in compressible liquid liquid water. After I use udf to change the equation of state of air to Tait&#8217;s equation, and derive the sound velocity equation according to Tait&#8217;s equation, both imported as compiled udf, I can&#8217;t calculate the velocity of compressible liquid liquid water over 20m\/s, where is the error that needs to be modified?&lt;\/p&gt;&lt;p&gt;Thank you.&lt;\/p&gt;&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/12\/22-12-2024-1734873650-mceclip0.png\" \/>&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-398209","topic","type-topic","status-publish","hentry","topic-tag-fluent-cfd-ansys-1","topic-tag-multiphase_models-1","topic-tag-2021-r1-1","topic-tag-udf"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27792"],"_bbp_topic_id":["398209"],"_bbp_subscription":["495803","199"],"_bbp_author_ip":["223.99.16.36"],"_bbp_last_reply_id":["398385"],"_bbp_last_active_id":["398385"],"_bbp_last_active_time":["2024-12-24 02:21:47"],"_bbp_reply_count":["12"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["2"],"_bbp_engagement":["495803","199"],"_btv_view_count":["288"],"_bbp_topic_status":["unanswered"],"_bbp_likes_count":["1"]},"test":"ntwy88126-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/398209","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\/398209\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=398209"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}