{"id":317826,"date":"2023-11-15T15:14:42","date_gmt":"2023-11-15T15:14:42","guid":{"rendered":"\/forum\/forums\/reply\/317826\/"},"modified":"2023-11-15T15:14:42","modified_gmt":"2023-11-15T15:14:42","slug":"317826","status":"publish","type":"reply","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/317826\/","title":{"rendered":"Reply To: High Mach number and Linear solver overflow fatal error"},"content":{"rendered":"<p>&lt;p&gt;Thanks for the answer.&lt;\/p&gt;&lt;p&gt;Yes I am using MRF, where volute and ported shroud are statinoary, and backspace, impeller and inlet region are rotating, which I connected with mixing plane interface. I tried different physical time step upto low as 2e-6 sec. but it is not working. on the other hand if I dont include backspace then it works, so now I am initialising &#8216;the complete model&#8217; with converge &#8216;without backspace model&#8217; and this time I am using local time scale value of 3, as it allows different physical time in different region depending on the speed of the flow. I will update if it works.&lt;\/p&gt;&lt;p&gt;By the way I use this speed ramping method and it works for this &#8216;without backspace model&#8217; but not for &#8216;with backspace model&#8217;, but in this study i used fixed physical time step.&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-317826","reply","type-reply","status-publish","hentry"],"aioseo_notices":[],"acf":[],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/replies\/317826","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/replies"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/reply"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/replies\/317826\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=317826"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}