{"id":342962,"date":"2024-01-03T15:27:31","date_gmt":"2024-01-03T15:27:31","guid":{"rendered":"\/forum\/forums\/topic\/question-about-lesson-6-of-ansys-learning-courses-method-of-characteristics\/"},"modified":"2024-01-03T15:27:31","modified_gmt":"2024-01-03T15:27:31","slug":"question-about-lesson-6-of-ansys-learning-courses-method-of-characteristics","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/question-about-lesson-6-of-ansys-learning-courses-method-of-characteristics\/","title":{"rendered":"Question about lesson 6 of Ansys learning courses (Method of characteristics)"},"content":{"rendered":"<p>Hi everyone,<\/p>\n<p>I have a question concerning the example in lesson 6 (<a href=\"https:\/\/www.youtube.com\/watch?v=k4RNsTLpbng&amp;t=670s\">(288) Method of Characteristics &mdash; Lesson 6 &#8211; YouTube<\/a>) on how to calculate the flow field of a CD nozzle with MOC. The lecturer starts in this example with point 2 that is situated in the throat of the CD nozzle. When I try to start my calculation at this point it fails, as the characteristic line is perpendicular to the flow. In the example the characteristitc line is not perpendicular but has a certain angle. How can I find this angle?&nbsp;<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/01\/03-01-2024-1704294714-mceclip0.png\"><\/p>\n<p>In the further course nu of point 5 is calculated by using the characteristic line C+ of point 3 and theta 5 of the expansion arc. I would assume, that theta and nu are already known on the expansion arc as they have the same value. I&#8217;ve also found this assumption in an open source NASA code<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/01\/03-01-2024-1704295426-mceclip1.png\"><\/p>\n<p>If this assumption is correct wouldn&#8217;t it be much easier to start the calculation with the characteristic lines on the expansion arc?<\/p>\n<p>I hope this makes any sense and somebody could help me out on this topic.<\/p>\n<p>Best regards<\/p>\n<p>Andreas Gebhardt<\/p>\n","protected":false},"template":"","class_list":["post-342962","topic","type-topic","status-closed","hentry","topic-tag-cd-nozzle","topic-tag-supersonic-flow-1","topic-tag-SupersonicNozzleFlow-1"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["336297","246845","348562"],"_bbp_author_ip":["96.7.74.173"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["558"],"_bbp_topic_status":["unanswered"],"_edit_lock":["1704296163:283129"],"_bbp_topic_id":["342962"],"_bbp_forum_id":["27825"],"_bbp_engagement":["246845","336297"],"_bbp_voice_count":["2"],"_bbp_reply_count":["1"],"_bbp_reply_count_hidden":["1"],"_bbp_last_reply_id":["349211"],"_bbp_last_active_id":["349211"],"_bbp_last_active_time":["2024-02-05 19:01:44"]},"test":"andreas-gebhardthowden-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/342962","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\/342962\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=342962"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}