{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/34022"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/34022","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Improvement In Acoustic Liner Attenuation In Turbofan Engines By Means Of Plasma Synthetic Jet Actuator","abstract":"Despite many advances in aviation noise control over the past 50 years, the industry is continually striving to reduce noise emissions. Turbofan engine acoustic liners are efficient attenuators of engine noise. Plasma actuators have been used as flow control devices in other settings and will now be studied as an enhancement for acoustic liners. A plasma actuator can excite oscillatory flow or a single direction (bias flow). Both flow types are studied as possible means to excite turbofan liners in order to improve the acoustic performance. Experiments revealed the oscillatory flow as the dominant factor in controlling resonator performance. The phase control of the actuator signal is an important parameter when dealing with the oscillatory flow. The actuator is first applied to a single resonator and then a set of six resonators. The experiments show that with the correct phase, the actuators improved the performance of a single resonator by 3 dB to 5 dB. The results for the array of actuators/resonators mirror the results of a single device. Beyond the improvements in performance, a number of other factors affect the usefulness of the plasma actuator technology in a turbofan environment. The ability of the actuator to produce plasma is susceptible to small imperfections in the device, and this property will likely be amplified in a perforated sheet with embedded actuators. Additional weight and energy consumed by the actuators is another factor to consider. Finally, plasma actuator operation produces ozone, so environmental effects deserve consideration as well.","abstract_html":"Despite many advances in aviation noise control over the past 50 years, the industry is continually striving to reduce noise emissions. Turbofan engine acoustic liners are efficient attenuators of engine noise. Plasma actuators have been used as flow control devices in other settings and will now be studied as an enhancement for acoustic liners. A plasma actuator can excite oscillatory flow or a single direction (bias flow). Both flow types are studied as possible means to excite turbofan liners in order to improve the acoustic performance. Experiments revealed the oscillatory flow as the dominant factor in controlling resonator performance. The phase control of the actuator signal is an important parameter when dealing with the oscillatory flow. The actuator is first applied to a single resonator and then a set of six resonators. The experiments show that with the correct phase, the actuators improved the performance of a single resonator by 3 dB to 5 dB. The results for the array of actuators/resonators mirror the results of a single device. Beyond the improvements in performance, a number of other factors affect the usefulness of the plasma actuator technology in a turbofan environment. The ability of the actuator to produce plasma is susceptible to small imperfections in the device, and this property will likely be amplified in a perforated sheet with embedded actuators. Additional weight and energy consumed by the actuators is another factor to consider. Finally, plasma actuator operation produces ozone, so environmental effects deserve consideration as well.","abstract_has_math":false,"creators":["Barnobi, Christopher Louis"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Mechanical Engineering","degree_department":"Mechanical Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["Fuller, Christopher R."],"committee_members":["Wicks, Alfred L.","Papenfuss, Cory M."],"year":2010,"date_issued":"2010-07-02","date_published":"2010-07-02","updated_at":"2026-07-22T22:18:53Z","subjects":["noise control","acoustic liner","turbofan","plasma synthetic jet actuator"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-07152010-120817"],"render_values":[{"text":"etd-07152010-120817","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/34022","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Fuller, Christopher R."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Wicks, Alfred L.","Papenfuss, Cory M."]},{"key":"dc:contributor.department","label":"Department","values":["Mechanical Engineering"]},{"key":"dc:creator","label":"Author","values":["Barnobi, Christopher Louis"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:41:31Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:41:31Z","2010-07-29"]},{"key":"dc:date.issued","label":"Date","values":["2010-07-02"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["noise control","acoustic liner","turbofan","plasma synthetic jet actuator"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-07152010-120817"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/34022"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Despite many advances in aviation noise control over the past 50 years, the industry is continually striving to reduce noise emissions. Turbofan engine acoustic liners are efficient attenuators of engine noise. Plasma actuators have been used as flow control devices in other settings and will now be studied as an enhancement for acoustic liners. A plasma actuator can excite oscillatory flow or a single direction (bias flow). Both flow types are studied as possible means to excite turbofan liners in order to improve the acoustic performance. Experiments revealed the oscillatory flow as the dominant factor in controlling resonator performance. The phase control of the actuator signal is an important parameter when dealing with the oscillatory flow. The actuator is first applied to a single resonator and then a set of six resonators. The experiments show that with the correct phase, the actuators improved the performance of a single resonator by 3 dB to 5 dB. The results for the array of actuators/resonators mirror the results of a single device. Beyond the improvements in performance, a number of other factors affect the usefulness of the plasma actuator technology in a turbofan environment. The ability of the actuator to produce plasma is susceptible to small imperfections in the device, and this property will likely be amplified in a perforated sheet with embedded actuators. Additional weight and energy consumed by the actuators is another factor to consider. Finally, plasma actuator operation produces ozone, so environmental effects deserve consideration as well."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["Improvement In Acoustic Liner Attenuation In Turbofan Engines By Means Of Plasma Synthetic Jet Actuator"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Fuller, Christopher R."],"dc:contributor.committeemember":["Wicks, Alfred L.","Papenfuss, Cory M."],"dc:contributor.department":["Mechanical Engineering"],"dc:creator":["Barnobi, Christopher Louis"],"dc:date.accessioned":["2014-03-14T20:41:31Z"],"dc:date.available":["2014-03-14T20:41:31Z","2010-07-29"],"dc:date.issued":["2010-07-02"],"dc:description.abstract":["Despite many advances in aviation noise control over the past 50 years, the industry is continually striving to reduce noise emissions. Turbofan engine acoustic liners are efficient attenuators of engine noise. Plasma actuators have been used as flow control devices in other settings and will now be studied as an enhancement for acoustic liners. A plasma actuator can excite oscillatory flow or a single direction (bias flow). Both flow types are studied as possible means to excite turbofan liners in order to improve the acoustic performance. Experiments revealed the oscillatory flow as the dominant factor in controlling resonator performance. The phase control of the actuator signal is an important parameter when dealing with the oscillatory flow. The actuator is first applied to a single resonator and then a set of six resonators. The experiments show that with the correct phase, the actuators improved the performance of a single resonator by 3 dB to 5 dB. The results for the array of actuators/resonators mirror the results of a single device. Beyond the improvements in performance, a number of other factors affect the usefulness of the plasma actuator technology in a turbofan environment. The ability of the actuator to produce plasma is susceptible to small imperfections in the device, and this property will likely be amplified in a perforated sheet with embedded actuators. Additional weight and energy consumed by the actuators is another factor to consider. Finally, plasma actuator operation produces ozone, so environmental effects deserve consideration as well."],"dc:description.degree":["Master of Science"],"dc:identifier.other":["etd-07152010-120817"],"dc:identifier.uri":["http://hdl.handle.net/10919/34022"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["noise control","acoustic liner","turbofan","plasma synthetic jet actuator"],"dc:title":["Improvement In Acoustic Liner Attenuation In Turbofan Engines By Means Of Plasma Synthetic Jet Actuator"],"dc:type":["Thesis"],"thesis:degree_discipline":["Mechanical Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:18:53Z"}