{"id":22882,"date":"2025-10-24T12:06:06","date_gmt":"2025-10-24T12:06:06","guid":{"rendered":"https:\/\/aerospacerepository.org\/?p=22882"},"modified":"2025-10-24T12:06:38","modified_gmt":"2025-10-24T12:06:38","slug":"flow-characteristics-verification-experiments-of-circular-to-obround-shape-transition-nozzle","status":"publish","type":"post","link":"https:\/\/aerospacerepository.org\/index.php\/2025\/10\/24\/flow-characteristics-verification-experiments-of-circular-to-obround-shape-transition-nozzle\/","title":{"rendered":"Flow characteristics verification experiments of circular to obround shape transition nozzle"},"content":{"rendered":"\n<p><strong>Su-Wan CHOI, Min-Seon JO, Bu-Kyeng SUNG, Si-Yoon KANG, Jeong-Yeol CHOI<\/strong><\/p>\n\n\n\n<p><strong>DOI Number: N\/A<\/strong><\/p>\n\n\n\n<p><strong>Conference number: HiSST-2025-150<\/strong><\/p>\n\n\n\n<p>This study presents the design and experimental verification of a Circular-to-Obround Shape Transition (COST) nozzle, proposed as a candidate configuration for scramjet combustors. Conventional scramjets are generally based on either axisymmetric or rectangular cross-sections, each with distinct advantages and drawbacks. Axisymmetric geometries provide structural efficiency and stable pseudo-shock behavior, while rectangular geometries facilitate effective mixing, visualization, and injector placement<br>but suffer from stronger boundary-layer effects and higher total pressure losses. To combine these advantages, an obround cross-section, composed of semicircular arcs and flat walls, was introduced as a novel alternative. The COST nozzle was designed to simulate high-altitude flight conditions, with exit Mach number 2 and static pressure 3 bar at the isolator entrance. Boundary-layer corrections were incorporated using Sivell\u2019s method. Experimental validation was performed by connecting the nozzle to the Vitiated Air Heater (VAH) facility at Pusan National University. Cold-flow wedge tests with high-speed Schlieren imaging confirmed uniform exit flow, with measured Mach numbers slightly above the<br>design value due to boundary-layer effects. The results demonstrate the feasibility of the COST nozzle and provide reference data for future investigations of obround scramjet isolator and combustor flow characteristics.<\/p>\n\n\n\n<p><a href=\"https:\/\/aerospacerepository.org\/wp-content\/uploads\/2025\/10\/HISST2025_150_paper.pdf\">Read the full paper here<\/a><\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p><b>Su-Wan CHOI, Min-Seon JO, Bu-Kyeng SUNG, Si-Yoon KANG, Jeong-Yeol CHOI<\/b><\/p>\n<p>DOI Number: N\/A<\/p>\n<p>Conference number: HiSST-2025-150<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[993,3367,3361],"tags":[1050,614,3624,744],"class_list":["post-22882","post","type-post","status-publish","format-standard","hentry","category-events","category-high-speed-aerodynamics-and-aerothermodynamics-with-application-to-hypersonic-regimes","category-1-hisst-2025","tag-nozzle-design","tag-scramjet","tag-shape-transition-nozzle","tag-supersonic-flow","category-993","category-3367","category-3361","description-off"],"_links":{"self":[{"href":"https:\/\/aerospacerepository.org\/index.php\/wp-json\/wp\/v2\/posts\/22882","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/aerospacerepository.org\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/aerospacerepository.org\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/aerospacerepository.org\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/aerospacerepository.org\/index.php\/wp-json\/wp\/v2\/comments?post=22882"}],"version-history":[{"count":1,"href":"https:\/\/aerospacerepository.org\/index.php\/wp-json\/wp\/v2\/posts\/22882\/revisions"}],"predecessor-version":[{"id":22885,"href":"https:\/\/aerospacerepository.org\/index.php\/wp-json\/wp\/v2\/posts\/22882\/revisions\/22885"}],"wp:attachment":[{"href":"https:\/\/aerospacerepository.org\/index.php\/wp-json\/wp\/v2\/media?parent=22882"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/aerospacerepository.org\/index.php\/wp-json\/wp\/v2\/categories?post=22882"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/aerospacerepository.org\/index.php\/wp-json\/wp\/v2\/tags?post=22882"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}