{"id":37340,"date":"2019-08-26T21:13:26","date_gmt":"2019-08-26T21:13:26","guid":{"rendered":"\/forum\/forums\/topic\/dynamic-pressure-higher-than-total-pressure\/"},"modified":"2019-08-26T21:13:26","modified_gmt":"2019-08-26T21:13:26","slug":"dynamic-pressure-higher-than-total-pressure","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/dynamic-pressure-higher-than-total-pressure\/","title":{"rendered":"Dynamic pressure higher than total pressure?"},"content":{"rendered":"<p>Hi,<\/p>\n<p><\/p>\n<p>Any help would be hugely appreciated on this confusing issue.<\/p>\n<p><\/p>\n<p>I&#8217;m modelling an external supersonic flow of M=2 around an aircraft. The boundary conditions are a pressure far field.<\/p>\n<p><\/p>\n<p>Using the isentropic flow relations, for my altitude (18,300m) the static pressure is 7,158 Pa, which using the isentropic flow relations gives a total pressure as 56,008 pa. I input this as the gauge pressure in the far field boundary condition.<\/p>\n<p><\/p>\n<p>Operating pressure is set to zero.<\/p>\n<p><\/p>\n<p>I set the simulation to provide me with dynamic pressure as I need to calculate a drag coefficient, however upon viewing it in Post, the dynamic pressure in the far field is ~3x higher than the total pressure I input??<\/p>\n<p><\/p>\n<p>Is there something I&#8217;m missing here? I&#8217;ve gone over my setup over and over and it seems fine.<\/p>\n<p><\/p>\n<p>Thanks very much in advance.<\/p>\n<p><\/p>\n<p>Ed.<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/49295d78-a446-41d0-a256-aab5015b0b70\/7f23fc21-7ee9-4b3e-9395-aab5015d9e0d_total-pressure.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/49295d78-a446-41d0-a256-aab5015b0b70\/0d311ed5-a5c0-461b-8e0c-aab5015d7f49_dynamic-pressure.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n","protected":false},"template":"","class_list":["post-37340","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["9516"],"_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","0"],"_btv_view_count":["1353"],"_bbp_subscription":["242389"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["37340"],"_bbp_forum_id":["27792"],"_bbp_engagement":["22555","167928"],"_bbp_voice_count":["2"],"_bbp_reply_count":["3"],"_bbp_last_reply_id":["92987"],"_bbp_last_active_id":["92987"],"_bbp_last_active_time":["2019-08-27 12:21:07"]},"test":"aerofrost"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/37340","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\/37340\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=37340"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}