{"557871":{"#nid":"557871","#data":{"type":"event","title":"PhD Defense by Aharon Karon","body":[{"value":"\u003Cp align=\u0022center\u0022\u003E\u003Cstrong\u003EPh.D. Thesis Defense\u003C\/strong\u003E\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003EBy\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003EAharon Z. Karon\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003EAdvisor: Prof. Krishan K. Ahuja\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003Cstrong\u003EPotential Factors Responsible for Discrepancies in Jet Noise Measurements of Different Studies\u003C\/strong\u003E\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E10:30 AM, Tuesday, August 16, 2016\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003Cem\u003EMontgomery Knight Building \u003C\/em\u003E\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003Cem\u003ERoom 317\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EABSTRACT:\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EJet noise measurements have been acquired at many anechoic jet-facilities around the world.\u0026nbsp; These measurements have been used to form the basis for prediction schemes and to understand the generation and radiation of jet noise.\u0026nbsp; Often, when jet noise measurements from different jet-facilities that are thought to be acquired at or corrected to similar conditions are compared, differences are observed in the spectra.\u0026nbsp; These comparisons are typically performed on the basis of the same nozzle-exit diameter, jet velocity, microphone distance from the jet flow, and ambient conditions.\u0026nbsp; This phenomenon has spurred much discussion in the aeroacoustics community, with some even claiming that some of the measurements are contaminated with rig-noise.\u0026nbsp; This study investigates following four factors that can be responsible for the differences in jet noise measurements: (1) rig noise contamination, (2) the jet\u2019s Reynolds number, (3) the nozzle-exit boundary layer of the jet, and (4) reflections and shielding from surfaces inside the anechoic jet-facility.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EFirst, the Doubling-Diameter Method, a scheme used to detect rig-noise contamination in jet-noise measurements, is verified and used on jet noise measurements acquired in the Georgia Tech Research Institute (GTRI) Anechoic Jet-Facility to verify the cleanliness of the jet noise measurements.\u0026nbsp; Second, the effect of Reynolds number of the jet is investigated qualitatively and quantitatively for its effect on jet noise measurements.\u0026nbsp; Third, the effect of the nozzle-exit boundary layer on jet noise measurements is categorized qualitatively and quantitatively.\u0026nbsp; In addition, a potential correction is developed that can be used to account for the differences in jet noise measurements from jets with different nozzle-exit boundary layer states.\u0026nbsp; Finally, surfaces inside the anechoic chamber itself, such as, the plenum chamber, and a secondary nozzle are investigated as potential reflectors and shields that can cause waviness and modifications in the jet noise spectra, respectively.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECommittee:\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EProf. Krishan K. Ahuja, School of Aerospace Engineering\u003C\/p\u003E\u003Cp\u003EProf. Jechiel Jagoda, School of Aerospace Engineering\u003C\/p\u003E\u003Cp\u003EProf. Lakshmi Sankar, School of Aerospace Engineering\u003C\/p\u003E\u003Cp\u003EDr. Donald K. Nance, NASA Marshall Space Flight Center\u003C\/p\u003E\u003Cp\u003EDr. Joseph Gavin, Gulfstream\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E \u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":"","field_summary_sentence":[{"value":"Potential Factors Responsible for Discrepancies in Jet Noise Measurements of Different Studies"}],"uid":"27707","created_gmt":"2016-08-02 11:48:06","changed_gmt":"2016-10-08 02:18:33","author":"Tatianna Richardson","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2016-08-16T11:30:00-04:00","event_time_end":"2016-08-16T13:30:00-04:00","event_time_end_last":"2016-08-16T13:30:00-04:00","gmt_time_start":"2016-08-16 15:30:00","gmt_time_end":"2016-08-16 17:30:00","gmt_time_end_last":"2016-08-16 17:30:00","rrule":null,"timezone":"America\/New_York"},"extras":[],"groups":[{"id":"221981","name":"Graduate Studies"}],"categories":[],"keywords":[{"id":"100811","name":"Phd Defense"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1788","name":"Other\/Miscellaneous"}],"invited_audience":[{"id":"78771","name":"Public"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}