Following the method used by these people: https:\/\/tfaws.nasa.gov\/TFAWS11\/Proceedings\/TFAWS2011-AE-001.pdf?fbclid=IwAR28cKI5Ghk_hSVQ5ckgZiXs3ibXEyAWBguCsy7cCUrd8aXHURRLa3gRX1E<\/a><\/p>\n
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I went from a simulation where I wasn’t satisfied about the results I got regarding the pressure coefficient results and the flow separation position. So I came back to my mesh and refined it nicely, with y+ consideration. My new results with a pressure-based method are way better than before, the target y+ is good and the pressure coefficient near the wall finally fits the experimental one.<\/p>\n
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BUT, when I switch to Density-based method, things go wrong. Simulation fails to start well and diverges very quickly. I tried everything : CFL number variation, changing from AUSM to FDS, using standard or hybrid initialization etc.<\/p>\n
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The methods used are:<\/span><\/p>\n <\/p>\n – Pressure Based Coupled Solver (PBCS) with 1\/ 2nd order for all equations<\/p>\n <\/p>\n – Density Based Solver (DBNS) with 2nd order for all equations<\/p>\n <\/p>\n Input parameters:<\/span><\/p>\n <\/p>\n Material:<\/strong> Air (ideal-gas)<\/p>\n <\/p>\n Model:<\/strong> SST k-omega (2 equ.)<\/p>\n <\/p>\n Boundary conditions:<\/strong> 1 pressure inlet (2.5 atm), 1 pressure outlet (1 atm)<\/p>\n <\/p>\n Solution method:<\/strong> AUSM – Least square – 2nd order<\/p>\n <\/p>\n Initialization method:<\/strong> Hybrid or Standard<\/p>\n <\/p>\n <\/p>\n <\/p>\n It seems like a shock wave is created at the first iteration (ignoring the initialization) and is at the origin of the divergence.<\/p>\n <\/p>\n I screened the first iterations :<\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n Do you have any idea what could be the origin of this failure?<\/p>\n <\/p>\n <\/p>\n <\/p>\n Best regards.<\/p>\n","protected":false},"template":"","class_list":["post-44461","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["16642"],"_bbp_old_topic_author_name_id":["Anonymous"],"_bbp_old_is_topic_anonymous_id":["false"],"_bbp_old_closed_status_id":["publish"],"_bbp_author_ip":[null],"_bbp_old_sticky_status_id":["normal"],"_bbp_likes_count":["0"],"_btv_view_count":["1762"],"_bbp_subscription":["240687"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["44461"],"_bbp_forum_id":["27792"],"_bbp_engagement":["59","118","166009"],"_bbp_voice_count":["3"],"_bbp_reply_count":["13"],"_bbp_last_reply_id":["116923"],"_bbp_last_active_id":["116923"],"_bbp_last_active_time":["2020-06-06 20:10:23"]},"test":"killian153"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/44461","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\/44461\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=44461"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/b45dcc9b-650f-48b5-bed2-aa6b007b5399\/791f24e9-c943-423a-82f6-abc8014c6116_first-shock.jpg?width=690&upscale=false\")
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