{"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":"

So I have a problem like this (actually it’s 3D):<\/p>\n

<\/p>\n

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. <\/p>\n

I started learning fluid simulation only because of this, so I don’t know alot and I am a beginner to this topic.<\/p>\n

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

First, I put the “sides” of the enclosure<\/strong> to wall <\/strong>and only the area infront and <\/strong>behinde the input\/output to pressure inlet and pressure outlet<\/strong>. But then I get problems with reversed flow<\/strong>. I think the enclosure is big enough, but I’m not completly sure. It seems already huge to me.<\/p>\n

Then I thought it is more correct to put 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 problems with the initialization<\/strong> and I can’t run the simulation at all..<\/p>\n

Can anyone help me? <\/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":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t