{"id":{"repo_id":"tamu","oai_identifier":"oai:oaktrust.library.tamu.edu:1969.1/1600962"},"canonical_url":"https://search.dev.ndltd.org/etd/tamu/oai:oaktrust.library.tamu.edu:1969.1/1600962","repository":{"repo_id":"tamu","name":"Texas A&M University","base_url":"https://oaktrust.library.tamu.edu/server/oai/request"},"display":{"title":"High Frequency Laser Energy Deposition for Hypersonic Active Flow Control on a Flared Cone","abstract":"Active flow control (AFC) in the hypersonic regime offers a promising method for rapid manipulation of the aerodynamic flow field without relying on traditional control surfaces, which can have actuation and flow field responses that are too slow for this high-speed regime. A practical AFC approach involves high-frequency laser energy deposition through the ablation of a metallic surface into the flow. The resulting laser-induced plume generates sustained transient changes downstream of the targeted flow field, effectively altering local high-speed flow parameters. This thesis applies the previously described energy deposition AFC technique to a modified NASA 91-6 flared cone to investigate downstream influence on the well-documented transitory behavior of the cone. Experiments were conducted in the Actively Controlled Expansion (ACE) hypersonic wind tunnel at the National Aerothermochemistry and Hypersonic Flight Laboratory (NAHL). The ACE tunnel variable nozzle enabled the collection of two test conditions per run. For each experiment, a pulse-burst laser (PBL) system, housed within the Aerospace Laboratory for Lasers, Electromagnetics, and Optics (ALLEMO), varied the laser's repetition rate and energy output. The PBL system enabled testing of three laser repetition rates, each of which varied the output energies. Testing conditions included four different Mach numbers at a targeted unit Reynolds number of 3 x 106. The campaign successfully captured flow-field and shock-wave manipulation, as well as amplification of the second mode instability and other transitory indicators within the hypersonic boundary layer. Laser-induced harmonics were observed at higher Mach numbers, consistent with the linear stability theory supporting Mack mode instabilities. Focused laser differential interferometry observed effects of the ablative plume absorbing energy when varying the laser system's output, while the pressure transducers captured ablation-induced transitory behaviors across the parameters of interest.","abstract_html":"Active flow control (AFC) in the hypersonic regime offers a promising method for rapid manipulation of the aerodynamic flow field without relying on traditional control surfaces, which can have actuation and flow field responses that are too slow for this high-speed regime. A practical AFC approach involves high-frequency laser energy deposition through the ablation of a metallic surface into the flow. The resulting laser-induced plume generates sustained transient changes downstream of the targeted flow field, effectively altering local high-speed flow parameters. This thesis applies the previously described energy deposition AFC technique to a modified NASA 91-6 flared cone to investigate downstream influence on the well-documented transitory behavior of the cone. Experiments were conducted in the Actively Controlled Expansion (ACE) hypersonic wind tunnel at the National Aerothermochemistry and Hypersonic Flight Laboratory (NAHL). The ACE tunnel variable nozzle enabled the collection of two test conditions per run. For each experiment, a pulse-burst laser (PBL) system, housed within the Aerospace Laboratory for Lasers, Electromagnetics, and Optics (ALLEMO), varied the laser's repetition rate and energy output. The PBL system enabled testing of three laser repetition rates, each of which varied the output energies. Testing conditions included four different Mach numbers at a targeted unit Reynolds number of 3 x 106. The campaign successfully captured flow-field and shock-wave manipulation, as well as amplification of the second mode instability and other transitory indicators within the hypersonic boundary layer. Laser-induced harmonics were observed at higher Mach numbers, consistent with the linear stability theory supporting Mack mode instabilities. Focused laser differential interferometry observed effects of the ablative plume absorbing energy when varying the laser system's output, while the pressure transducers captured ablation-induced transitory behaviors across the parameters of interest.","abstract_has_math":false,"creators":["Vijayakumar, Jenith 2001-"],"institution":"Texas A&M University","degree_name":"Master of Science","degree_level":null,"degree_discipline":"Aerospace Engineering","degree_department":null,"school":null,"contributors":[],"advisors":["Tichenor, Nathan"],"committee_chairs":[],"committee_members":["Siddiqui, Farhan","Staack, David"],"year":2025,"date_issued":"2025-12","date_published":"2025-12","updated_at":"2026-08-21T16:48:44Z","subjects":["Engineering, Aerospace"],"languages":["English"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/1969.1/1600962","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"source_record":{"url":"https://oaktrust.library.tamu.edu/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Aoaktrust.library.tamu.edu%3A1969.1%2F1600962","prefix":"dim"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Tichenor, Nathan"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Siddiqui, Farhan","Staack, David"]},{"key":"dc:creator","label":"Author","values":["Vijayakumar, Jenith 2001-"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2026-03-05T22:06:18Z"]},{"key":"dc:date.issued","label":"Date","values":["2025-12"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Aerospace Engineering"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Texas A&M University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Engineering, Aerospace"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["English"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/1969.1/1600962"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Active flow control (AFC) in the hypersonic regime offers a promising method for rapid manipulation of the aerodynamic flow field without relying on traditional control surfaces, which can have actuation and flow field responses that are too slow for this high-speed regime. A practical AFC approach involves high-frequency laser energy deposition through the ablation of a metallic surface into the flow. The resulting laser-induced plume generates sustained transient changes downstream of the targeted flow field, effectively altering local high-speed flow parameters. This thesis applies the previously described energy deposition AFC technique to a modified NASA 91-6 flared cone to investigate downstream influence on the well-documented transitory behavior of the cone. Experiments were conducted in the Actively Controlled Expansion (ACE) hypersonic wind tunnel at the National Aerothermochemistry and Hypersonic Flight Laboratory (NAHL). The ACE tunnel variable nozzle enabled the collection of two test conditions per run. For each experiment, a pulse-burst laser (PBL) system, housed within the Aerospace Laboratory for Lasers, Electromagnetics, and Optics (ALLEMO), varied the laser's repetition rate and energy output. The PBL system enabled testing of three laser repetition rates, each of which varied the output energies. Testing conditions included four different Mach numbers at a targeted unit Reynolds number of 3 x 106. The campaign successfully captured flow-field and shock-wave manipulation, as well as amplification of the second mode instability and other transitory indicators within the hypersonic boundary layer. Laser-induced harmonics were observed at higher Mach numbers, consistent with the linear stability theory supporting Mack mode instabilities. Focused laser differential interferometry observed effects of the ablative plume absorbing energy when varying the laser system's output, while the pressure transducers captured ablation-induced transitory behaviors across the parameters of interest."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["High Frequency Laser Energy Deposition for Hypersonic Active Flow Control on a Flared Cone"]}]}],"canonical_facts":{"dc:contributor.advisor":["Tichenor, Nathan"],"dc:contributor.committeemember":["Siddiqui, Farhan","Staack, David"],"dc:creator":["Vijayakumar, Jenith 2001-"],"dc:date.accessioned":["2026-03-05T22:06:18Z"],"dc:date.issued":["2025-12"],"dc:description.abstract":["Active flow control (AFC) in the hypersonic regime offers a promising method for rapid manipulation of the aerodynamic flow field without relying on traditional control surfaces, which can have actuation and flow field responses that are too slow for this high-speed regime. A practical AFC approach involves high-frequency laser energy deposition through the ablation of a metallic surface into the flow. The resulting laser-induced plume generates sustained transient changes downstream of the targeted flow field, effectively altering local high-speed flow parameters. This thesis applies the previously described energy deposition AFC technique to a modified NASA 91-6 flared cone to investigate downstream influence on the well-documented transitory behavior of the cone. Experiments were conducted in the Actively Controlled Expansion (ACE) hypersonic wind tunnel at the National Aerothermochemistry and Hypersonic Flight Laboratory (NAHL). The ACE tunnel variable nozzle enabled the collection of two test conditions per run. For each experiment, a pulse-burst laser (PBL) system, housed within the Aerospace Laboratory for Lasers, Electromagnetics, and Optics (ALLEMO), varied the laser's repetition rate and energy output. The PBL system enabled testing of three laser repetition rates, each of which varied the output energies. Testing conditions included four different Mach numbers at a targeted unit Reynolds number of 3 x 106. The campaign successfully captured flow-field and shock-wave manipulation, as well as amplification of the second mode instability and other transitory indicators within the hypersonic boundary layer. Laser-induced harmonics were observed at higher Mach numbers, consistent with the linear stability theory supporting Mack mode instabilities. Focused laser differential interferometry observed effects of the ablative plume absorbing energy when varying the laser system's output, while the pressure transducers captured ablation-induced transitory behaviors across the parameters of interest."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["https://hdl.handle.net/1969.1/1600962"],"dc:language.iso":["English"],"dc:subject":["Engineering, Aerospace"],"dc:title":["High Frequency Laser Energy Deposition for Hypersonic Active Flow Control on a Flared Cone"],"dc:type":["Thesis"],"thesis:degree_discipline":["Aerospace Engineering"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Texas A&M University"]},"updated_at":"2026-08-21T16:48:44Z"}