{"id":309549,"date":"2023-09-30T17:54:13","date_gmt":"2023-09-30T17:54:13","guid":{"rendered":"\/forum\/forums\/topic\/what-are-the-bcs-of-this-problemproblem-with-reversed-flow-or-initialization\/"},"modified":"2023-09-30T18:03:02","modified_gmt":"2023-09-30T18:03:02","slug":"what-are-the-bcs-of-this-problemproblem-with-reversed-flow-or-initialization","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/what-are-the-bcs-of-this-problemproblem-with-reversed-flow-or-initialization\/","title":{"rendered":"What are the BCs of this problem?(Problem with reversed flow or  initialization)"},"content":{"rendered":"<p>So I have a problem like this (actually it&#8217;s 3D):<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/09\/30-09-2023-1696096974-mceclip0.png\"><\/p>\n<p>The black box sucks the air in (with a fan) and transports it to the output, where it gets out. I am not interested of the simulation of the air inside the black box, I only want to simulate the air around it \/ infront of it. So I want to know, how the surrounding air is sucked inside the box.&nbsp;<\/p>\n<p>I started learning fluid simulation only because of this, so I don&#8217;t know alot and I am a beginner to this topic.<\/p>\n<p>I think I managed the BCs of the black box corret (all walls except the input\/output areas where the mass flow leaves\/enters the box). But I have struggle with the enclosure..<\/p>\n<p>First, I put the &#8220;sides&#8221; of the <strong>enclosure<\/strong> <strong>to wall <\/strong>and only the area infront <strong>and <\/strong>behinde the input\/output <strong>to pressure inlet and pressure outlet<\/strong>. But then I get <strong>problems with reversed flow<\/strong>. I think the enclosure is big enough, but I&#8217;m not completly sure. It seems already huge to me.<\/p>\n<p>Then I thought it is more correct to put <strong>all the side of the enclosure to pressure inlet or pressure outlet<\/strong>, since the air is able to leave or enter the part of any side of the enclosure. If I try that, I get <strong>problems with the initialization<\/strong> and I can&#8217;t run the simulation at all..<\/p>\n<p>Can anyone help me?&nbsp;<\/p>\n","protected":false},"template":"","class_list":["post-309549","topic","type-topic","status-closed","hentry","topic-tag-bcs","topic-tag-boundary-conditions","topic-tag-enclosure","topic-tag-hybrid-initialization","topic-tag-initialization","topic-tag-reverse-flow-2","topic-tag-reversed-flow"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["292260","13659"],"_bbp_author_ip":["96.7.218.223"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["437"],"_edit_lock":["1696096964:229002"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["309549"],"_bbp_forum_id":["27792"],"_bbp_engagement":["13659","292260"],"_bbp_voice_count":["2"],"_bbp_reply_count":["1"],"_bbp_last_reply_id":["309673"],"_bbp_last_active_id":["309673"],"_bbp_last_active_time":["2023-10-02 14:50:23"]},"test":"j-sprengeltu-bs-de"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/309549","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\/309549\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=309549"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}