https://peertube.dngr.us/videos/watch/89f899a6-169d-4248-8cbe-cdbcc72c23d1 Classic tonal screech noise created by under-expanded supersonic jets; Long Penetration Mode (LPM) supersonic phenomenon -Under-expanded counter-flowing jet in supersonic free stream -Demonstrated in several wind tunnel tests -Modeled in several computational fluid dynamics (CFD) simulations; Discussion of LPM acoustics feedback and fluid interactions -Analogous to the aero-acoustics interactions seen in screech jets; Lessons Learned: Applying certain methodologies to LPM -Developed and successfully demonstrated in the study of screech jets -Discussion of mechanically induced excitation in fluid oscillators in general; Conclusions -Large body of work done on jet screech, other aero-acoustic phenomenacan have direct application to the study and applications of LPM cold flow jets. For the Oral/Visual Presentation in which this video was presented, please see the following link in the NASA Technical Reports Server (NTRS, http://ntrs.nasa.gov): http://hdl.handle.net/2060/20150016244 Mirrored from YouTube: https://youtu.be/afL8mZwFwMI Original channel: NASA STI Program Wed, 15 Jul 2026 12:49:57 GMT https://validator.w3.org/feed/docs/rss2.html PeerTube - https://peertube.dngr.us https://peertube.dngr.us/lazy-static/avatars/ec5edb1e-3795-4978-be4f-c67e98fbc992.png https://peertube.dngr.us/videos/watch/89f899a6-169d-4248-8cbe-cdbcc72c23d1 All rights reserved, unless otherwise specified in the terms specified at https://peertube.dngr.us/about and potential licenses granted by each content's rightholder.