Is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a boundary to the local speed of sound. It is named after the Czech physicist and philosopher Ernst Mach.<\/p>\n\n\n\n
where:<\/p>\n\n\n\n
M is the local Mach number,<\/p>\n\n\n\n
u<\/em> is the local flow velocity with respect to the boundaries (either internal, such as an object immersed in the flow, or external, like a channel), and<\/p>\n\n\n\n c<\/em> is the speed of sound in the medium, which in air varies with the square root of the thermodynamic temperature.<\/p>\n\n\n\n By definition, at Mach 1, the local flow velocity u<\/em> is equal to the speed of sound. At Mach 0.65, u<\/em> is 65% of the speed of sound (subsonic), and, at Mach 1.35, u<\/em> is 35% faster than the speed of sound (supersonic). Pilots of high-altitude aerospace vehicles use flight Mach number to express a vehicle’s true airspeed, but the flow field around a vehicle varies in three dimensions, with corresponding variations in local Mach number.<\/p>\n","protected":false},"excerpt":{"rendered":" Is a\u00a0dimensionless quantity\u00a0in\u00a0fluid dynamics\u00a0representing the ratio of\u00a0flow velocity\u00a0past a\u00a0boundary\u00a0to the local\u00a0speed of sound.\u00a0It is named after the\u00a0Czech\u00a0physicist and philosopher\u00a0Ernst Mach. where: M is the local Mach number, u is the local flow velocity with respect to the boundaries (either internal, such as an object immersed in the flow, or external, like a channel), and c is the speed…<\/p>\n","protected":false},"author":8,"featured_media":0,"menu_order":0,"template":"","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"class_list":["post-2201","glossary","type-glossary","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.ca-tz.org\/index.php\/wp-json\/wp\/v2\/glossary\/2201"}],"collection":[{"href":"https:\/\/www.ca-tz.org\/index.php\/wp-json\/wp\/v2\/glossary"}],"about":[{"href":"https:\/\/www.ca-tz.org\/index.php\/wp-json\/wp\/v2\/types\/glossary"}],"author":[{"embeddable":true,"href":"https:\/\/www.ca-tz.org\/index.php\/wp-json\/wp\/v2\/users\/8"}],"version-history":[{"count":1,"href":"https:\/\/www.ca-tz.org\/index.php\/wp-json\/wp\/v2\/glossary\/2201\/revisions"}],"predecessor-version":[{"id":2838,"href":"https:\/\/www.ca-tz.org\/index.php\/wp-json\/wp\/v2\/glossary\/2201\/revisions\/2838"}],"wp:attachment":[{"href":"https:\/\/www.ca-tz.org\/index.php\/wp-json\/wp\/v2\/media?parent=2201"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}