{"id":159419,"date":"2021-06-12T08:35:42","date_gmt":"2021-06-12T08:35:42","guid":{"rendered":"\/forum\/forums\/topic\/question-about-steady-state-and-transient-simulation\/"},"modified":"2021-06-15T13:42:53","modified_gmt":"2021-06-15T13:42:53","slug":"question-about-steady-state-and-transient-simulation","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/question-about-steady-state-and-transient-simulation\/","title":{"rendered":"Question about steady-state and transient simulation"},"content":{"rendered":"
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Hi,<\/p>\n

I have a question about steady-state and transient simulation. <\/p>\n

I am simulating a heat problem with natural convection in a closed domain with the aim on the stationary solution.<\/p>\n

Since my temperature differences are high (between 850°C in the inside of the simulated ofen, and 20°C on the outside of the closed domain with simulated free stream convection), so I can not use bousinessq. The Ansys-Fluent user guide says, I have to use transient simulation, to simulate the right mass inside the closed domain.<\/p>\n

<\/p>\n<\/p>\n

Fluent user's guide:<\/p>\n

When you model natural convection inside a closed domain, the solution will depend on the mass inside the domain. Since this mass will not be known unless the density is known, you must model the flow in one of the following ways:<\/p>\n

Perform a transient calculation. In this approach, the initial density will be computed from the initial pressure and temperature, so the initial mass is known. As the solution progresses over time, this mass will be properly conserved. If the temperature differences in your domain are large, you must follow this approach.<\/p>\n

<\/p>\n<\/p>\n

The thing is, in reality the closed domain is not air-tight. So the mass and density don't have to be conserved. In fact, it would be wrong. <\/p>\n

<\/p>\n<\/p>\n

So the thing is, I tried both transient and steady-state simulation and obviously get different solutions. I have learned from almost all the discussions, it is up to the person in front of the simulation to decide, whether it is a good solution or not. <\/p>\n

<\/p>\n<\/p>\n

But I just don't know, which is the right choice. <\/p>\n

<\/p>\n<\/p>\n

Help is very much appreciated and thanks in advance<\/p>\n","protected":false},"template":"","class_list":["post-159419","topic","type-topic","status-closed","hentry","topic-tag-fluent","topic-tag-steady-state","topic-tag-transient-simulation"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_author_ip":[""],"_bbp_old_reply_author_name_id":["Anonymous"],"_bbp_old_is_reply_anonymous_id":["false"],"_btv_view_count":["2567"],"_bbp_likes_count":["0"],"_bbp_subscription":["241886"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["159419"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","202288"],"_bbp_voice_count":["2"],"_bbp_reply_count":["8"],"_bbp_last_reply_id":["181936"],"_bbp_last_active_id":["181936"],"_bbp_last_active_time":["2021-06-15 13:42:53"]},"test":"konrad-boeckergmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/159419","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\/159419\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=159419"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}