{"id":383066,"date":"2024-09-19T03:55:08","date_gmt":"2024-09-19T03:55:08","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/definition-of-specified-flux-boundary-condition-for-a-uds-on-a-wall\/"},"modified":"2024-09-19T03:57:36","modified_gmt":"2024-09-19T03:57:36","slug":"definition-of-specified-flux-boundary-condition-for-a-uds-on-a-wall","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/definition-of-specified-flux-boundary-condition-for-a-uds-on-a-wall\/","title":{"rendered":"Definition of specified flux boundary condition for a UDS on a wall"},"content":{"rendered":"

<p><p>Hi, <\/p><p>I have set-up a user defined scalar to be solve in fluent. It uses the default unsteady function and mass flow rate as the flux function. In other words, I have implemented a scalar transport equation with the scalar having the units of #\/kg. <\/p><p>In my case, the scalar is actually space charge and have the unit Coulombs\/kg (C\/kg).<\/p><p>Hence, with mass flow rate as the flux function (density*velocity = (kg\/(m^2.s))), the units of the advection terms are C\/(m^2.s). <\/p><p>My questions are:<\/p><\/p><\/p>\n

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  1. If I specify the BC of this UDS as “specified value”, I assume the unit would be in C\/kg. Is this correct?<\/li>\n
  2. If I specify the BC of this UDS as “specified flux”, is the unit C\/(m^2.s) or something else?<\/li>\n
  3. If I specify the BC as “specified flux = 0”, on a wall (where no flow can go through), it means the wall is insulating the charge correct? But does it mean zero gradient on the charge near the wall?<\/li>\n
  4. If I specify the BC as “specified flux = 0”, on an outlet (where flow can go through), it means that charge is still advected out, but the gradient of charge is set to zero correct?<\/li>\n
  5. If I specify the BC on a wall as “specified flux”, and set it not equal to zero, say x, does the wall then act like a source\/sink, where charge is being inserted\/deleted to at a rate of x C\/(m^2.s)? If so, does that then mean +x is act as sink and -x act as source?<\/li>\n<\/ol>\n

    <p><p> <\/p><p> <\/p><\/p><\/p>\n","protected":false},"template":"","class_list":["post-383066","topic","type-topic","status-publish","hentry","topic-tag-boundary-conditions","topic-tag-fluent-uds","topic-tag-fluent-uds-udf-1"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["451626","199"],"_bbp_author_ip":["193.114.139.226"],"_btv_view_count":["1052"],"_bbp_topic_status":["unanswered"],"_edit_last":["451626"],"_bbp_likes_count":["1"],"_bbp_topic_id":["383066"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","451626"],"_bbp_voice_count":["2"],"_bbp_reply_count":["2"],"_bbp_last_reply_id":["383202"],"_bbp_last_active_id":["383202"],"_bbp_last_active_time":["2024-09-19 14:35:52"]},"test":"adi959719gmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/383066","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\/383066\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=383066"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}