{"id":326627,"date":"2023-12-06T12:48:32","date_gmt":"2023-12-06T12:48:32","guid":{"rendered":"\/forum\/forums\/topic\/modifiying-governing-equations-in-ansys-fluent-for-a-case-2-diffusion-model\/"},"modified":"2023-12-06T12:48:32","modified_gmt":"2023-12-06T12:48:32","slug":"modifiying-governing-equations-in-ansys-fluent-for-a-case-2-diffusion-model","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/modifiying-governing-equations-in-ansys-fluent-for-a-case-2-diffusion-model\/","title":{"rendered":"Modifiying governing equations in Ansys Fluent for a case 2 diffusion model"},"content":{"rendered":"<p>Hello!<\/p>\n<p>I am new to Ansys Fluent and I have a question regarding UDFs and UDSs.<\/p>\n<p>I&#8217;d like to model a special case of diffusion governed by non-conventional equations, provided below.<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/12\/06-12-2023-1701865991-governing eqs.png\" alt=\"\"><\/p>\n<p>The first equation is the diffusion equation and well known.<\/p>\n<p>The second equation is an alterted version of Ficks&#8217;s first law, including a term taking the conformational changes of a material the species diffuses through into account.&nbsp;<\/p>\n<p>The third equation describes the time-evolution of the material&#8217;s changes.<\/p>\n<p>All variables will be scalars as I will model the diffusion only in 1-D.<\/p>\n<p>As far as I can tell, simple cases of Fickian diffusion are modelled analogously via heat conduction.<\/p>\n<p>I would like to know if it is even possible to adapt the default equations and add necessary ones to include the full model I want to implement, via UDFs and UDSs.<\/p>\n<p>If so, which UDFs would I need to use?<\/p>\n<p>Thanks in advance,<\/p>\n<p>Tino<\/p>\n","protected":false},"template":"","class_list":["post-326627","topic","type-topic","status-closed","hentry","topic-tag-diffusion","topic-tag-fluent-uds-udf-1","topic-tag-governing-equations","topic-tag-permeability-2"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["303799","199"],"_bbp_author_ip":["23.206.193.146"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["484"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["326627"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","303799"],"_bbp_voice_count":["2"],"_bbp_reply_count":["3"],"_bbp_last_reply_id":["326689"],"_bbp_last_active_id":["326689"],"_bbp_last_active_time":["2023-12-06 15:07:11"]},"test":"e11713116student-tuwien-ac-at"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/326627","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\/326627\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=326627"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}