{"id":23235,"date":"2025-10-26T11:38:06","date_gmt":"2025-10-26T11:38:06","guid":{"rendered":"https:\/\/aerospacerepository.org\/?p=23235"},"modified":"2025-10-26T11:38:07","modified_gmt":"2025-10-26T11:38:07","slug":"sound-generation-by-entropy-inhomogeneity-within-thermally-choked-flow-nozzle","status":"publish","type":"post","link":"https:\/\/aerospacerepository.org\/index.php\/2025\/10\/26\/sound-generation-by-entropy-inhomogeneity-within-thermally-choked-flow-nozzle\/","title":{"rendered":"Sound generation by entropy inhomogeneity within thermally-choked-flow nozzle"},"content":{"rendered":"\n<p><strong>Fr\u00e9d\u00e9ric OLIVON, Antoine CH\u00c9DIN, Jean-Etienne DURAND, Aur\u00e9lien GENOT, Estelle PIOT<\/strong><\/p>\n\n\n\n<p><strong>DOI Number: N\/A<\/strong><\/p>\n\n\n\n<p><strong>Conference number: HiSST-2025-042<\/strong><\/p>\n\n\n\n<p>The indirect entropy noise generation in a thermally choked flow nozzle, induced by the convection of 2D circular entropy spots, is investigated. Two configurations are examined: a thermal throat formed by non-uniform volumetric heat addition, and an equivalent isentropic nozzle with a geometric throat. Both are designed to produce the same steady Mach number distribution, in order to isolate the influence of heat addition on the acoustic response. The analysis combines two-dimensional CFD simulations with two asymptotic one-dimensional models: the quasi-steady (QSS) model, adapted for large spots, and the point-mass (PM) inertial model, for small spots. For the geometric-throat case, the CFD results<br>show fair agreement with both the QSS and PM predictions in their respective asymptotic regimes. For the thermal-throat case, the QSS regime is reached for spots larger than 100 throat radius, which is a value lower than that of the geometric configuration. Then, the acoustic response exceeds QSS predictions (\u223c 20%), which is certainly due to the invalidity of the assumption of no Mach fluctuations at the throat. In the small-spot limit, the PM model predicts the inertial regime with reasonable accuracy for both configurations, but at different spot radii. The thermal-throat case, however, deviates from the PM prediction, highlighting fundamental differences between heated and isentropic nozzles and the need to<br>extend asymptotic models to non-isentropic base flows.<\/p>\n\n\n\n<p><a href=\"https:\/\/aerospacerepository.org\/wp-content\/uploads\/2025\/10\/HISST2025_42_paper.pdf\">Read the full paper here<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p><b>Fr\u00e9d\u00e9ric OLIVON, Antoine CH\u00c9DIN, Jean-Etienne DURAND, Aur\u00e9lien GENOT, Estelle PIOT<\/b><\/p>\n<p>DOI Number: N\/A<\/p>\n<p>Conference number: HiSST-2025-042<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[993,3361,3363],"tags":[3731,1884,3732,1615],"class_list":["post-23235","post","type-post","status-publish","format-standard","hentry","category-events","category-1-hisst-2025","category-propulsion-systems-components","tag-combustion-instabilities","tag-dual-mode-ramjet","tag-indirect-entropy-noise","tag-thermal-throat","category-993","category-3361","category-3363","description-off"],"_links":{"self":[{"href":"https:\/\/aerospacerepository.org\/index.php\/wp-json\/wp\/v2\/posts\/23235","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=23235"}],"version-history":[{"count":1,"href":"https:\/\/aerospacerepository.org\/index.php\/wp-json\/wp\/v2\/posts\/23235\/revisions"}],"predecessor-version":[{"id":23237,"href":"https:\/\/aerospacerepository.org\/index.php\/wp-json\/wp\/v2\/posts\/23235\/revisions\/23237"}],"wp:attachment":[{"href":"https:\/\/aerospacerepository.org\/index.php\/wp-json\/wp\/v2\/media?parent=23235"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/aerospacerepository.org\/index.php\/wp-json\/wp\/v2\/categories?post=23235"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/aerospacerepository.org\/index.php\/wp-json\/wp\/v2\/tags?post=23235"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}