{"id":318728,"date":"2023-11-21T07:32:59","date_gmt":"2023-11-21T07:32:59","guid":{"rendered":"\/forum\/forums\/topic\/how-to-make-my-simulation-converge\/"},"modified":"2023-11-27T16:13:18","modified_gmt":"2023-11-27T16:13:18","slug":"how-to-make-my-simulation-converge","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-to-make-my-simulation-converge\/","title":{"rendered":"How to make my simulation converge?"},"content":{"rendered":"

Hello everyone, <\/p>\n

I’m a master’s student and relatively new to Ansys Fluent. Since September, I have been learning how to use it from scratch by myself.  <\/p>\n

I’m writing this post because I’m struggling to let my simulation for an abrupt expansion pipe converge. <\/p>\n

The geometry of my abrupt expansion pipe is like this: 
\"\"<\/p>\n

Mesh qualities: 
– Minimum Orthogonal Quality: 0.16
– Maximum skewness: 0.39
(According to the manual, these qualities seem to be okay, though it’s not that good.)<\/p>\n

The setup in Fluent that I did is the following: <\/p>\n

Solver setting in General: 
– Type: Pressure-Based
– Velocity Formulation: Absolute
– Time: Steady<\/p>\n

Since the flow is laminar(Re for the thin pipe = 2000, Re for the thick pipe = 666), I choose the Laminar model. <\/p>\n

Boundary conditions: 
– Inlet velocity = 0.172 m\/s
– Outlet pressure: Gauge pressure = 0 Pa<\/p>\n

When I set smaller inlet velocity (0.001 m\/s, 0.003 m\/s, 0.005 m\/s, 0.011 m\/s, 0.021 m\/s, 0.043 m\/s), the simulation successfully converged. However, with a larger inlet velocity like this time (0.172 m\/s), the simulation no longer converges… <\/p>\n

I tried the following solutions, but none worked well:  
– Increase the number of iterations 
– Change fluid time scale
– Change relaxation factors<\/p>\n

I have been trying my best to think about possible solutions by myself, but unfortunately, I have not succeeded. I would appreciate it if some of you could give me possible suggestions. <\/p>\n","protected":false},"template":"","class_list":["post-318728","topic","type-topic","status-closed","hentry","topic-tag-convergence-issue","topic-tag-laminar-flow","topic-tag-laminar-pipe-flow-1"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["45857","199"],"_bbp_author_ip":["23.206.193.146"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_bbp_likes_count":["0"],"_btv_view_count":["1373"],"_bbp_status":["publish"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["318728"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","45857"],"_bbp_voice_count":["2"],"_bbp_reply_count":["8"],"_bbp_last_reply_id":["319608"],"_bbp_last_active_id":["319608"],"_bbp_last_active_time":["2023-11-27 16:06:23"]},"test":"okutsu-t-acm-titech-ac-jp"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/318728","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\/318728\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=318728"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}