{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/104909"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/104909","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Aerodynamic characterization of a Griffith-type transonic, laminar-flow airfoil","abstract":"An experimental investigation was conducted at the University of Illinois’ Transonic Wind Tunnel Facility on a Griffith-type transonic airfoil to evaluate the effectiveness of its laminar flow qualities and boundary-layer flow-control characteristics in the transonic regime. Airfoil surface and wake pressure data were acquired to characterize the aerodynamic performance across a range of α = -2˚ to 2˚ and M = 0.3 to 0.7. In addition, surface-oil flow visualization, PIV, and Schlieren imaging were performed to identify the suction influence on boundary-layer transition, momemtum deficit alleviation in the wake, and stability of transonic shocks. It was observed from the pressure distributions that the flow control application had a beneficial influence, allowing for a more aggressive pressure recovery downstream of the suction slot resulting in higher recovery pressure values at the trailing edge. At the design conditions of M = 0.7 and α = 0˚, a net profile drag reduction of 10.70% and an increase in the lift-to-drag ratio of 14.68% were observed when compared to no-suction conditions. Velocity flow field contours obtained from the PIV data showed an increase in the wake velocity magnitude for all Mach numbers at α = 0˚, displaying excellent agreement for the drag data at these conditions. Surface-oil flow visualization experiments revealed that the airfoil experienced extensive laminar flow runs regardless of suction application due to the low-Reynolds number test condition. The laminar flow was found to be shock limited followed by a laminar separation bubble in most cases. From the Schlieren experiments, a characteristic frequency of 22.38 Hz for the shock oscillatory process was identified at the design conditions which also was observed to stabilize under the influence of suction. In general, the improvements in aerodynamic efficiency and stability of the shock resulting from suction were observed to be greatest at higher angles of attack where the boundary layer was subjected to stronger-unforced pressure gradients.","abstract_html":"An experimental investigation was conducted at the University of Illinois’ Transonic Wind Tunnel Facility on a Griffith-type transonic airfoil to evaluate the effectiveness of its laminar flow qualities and boundary-layer flow-control characteristics in the transonic regime. Airfoil surface and wake pressure data were acquired to characterize the aerodynamic performance across a range of α = -2˚ to 2˚ and M = 0.3 to 0.7. In addition, surface-oil flow visualization, PIV, and Schlieren imaging were performed to identify the suction influence on boundary-layer transition, momemtum deficit alleviation in the wake, and stability of transonic shocks. It was observed from the pressure distributions that the flow control application had a beneficial influence, allowing for a more aggressive pressure recovery downstream of the suction slot resulting in higher recovery pressure values at the trailing edge. At the design conditions of M = 0.7 and α = 0˚, a net profile drag reduction of 10.70% and an increase in the lift-to-drag ratio of 14.68% were observed when compared to no-suction conditions. Velocity flow field contours obtained from the PIV data showed an increase in the wake velocity magnitude for all Mach numbers at α = 0˚, displaying excellent agreement for the drag data at these conditions. Surface-oil flow visualization experiments revealed that the airfoil experienced extensive laminar flow runs regardless of suction application due to the low-Reynolds number test condition. The laminar flow was found to be shock limited followed by a laminar separation bubble in most cases. From the Schlieren experiments, a characteristic frequency of 22.38 Hz for the shock oscillatory process was identified at the design conditions which also was observed to stabilize under the influence of suction. In general, the improvements in aerodynamic efficiency and stability of the shock resulting from suction were observed to be greatest at higher angles of attack where the boundary layer was subjected to stronger-unforced pressure gradients.","abstract_has_math":false,"creators":["Collazo Garcia III, Armando Rafael"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Aerospace Engineering","degree_department":null,"school":null,"contributors":["Ansell, Phillip J."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2019,"date_issued":"2019-08-23T20:01:14Z","date_published":"2019-08-23T20:01:14Z","updated_at":"2026-07-22T22:24:42Z","subjects":["transonic, laminar flow, flow control, airfoil, wind tunnel"],"languages":["en"],"rights":["© 2019 by Armando R. Collazo Garcia III. All rights reserved."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/104909","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Ansell, Phillip J."]},{"key":"dc:creator","label":"Author","values":["Collazo Garcia III, Armando Rafael"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2019-08-23T20:01:14Z","2019-04-23","2019-05"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Aerospace Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["transonic, laminar flow, flow control, airfoil, wind tunnel"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["© 2019 by Armando R. Collazo Garcia III. All rights reserved."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/104909"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["An experimental investigation was conducted at the University of Illinois’ Transonic Wind Tunnel Facility on a Griffith-type transonic airfoil to evaluate the effectiveness of its laminar flow qualities and boundary-layer flow-control characteristics in the transonic regime. Airfoil surface and wake pressure data were acquired to characterize the aerodynamic performance across a range of α = -2˚ to 2˚ and M = 0.3 to 0.7. In addition, surface-oil flow visualization, PIV, and Schlieren imaging were performed to identify the suction influence on boundary-layer transition, momemtum deficit alleviation in the wake, and stability of transonic shocks. It was observed from the pressure distributions that the flow control application had a beneficial influence, allowing for a more aggressive pressure recovery downstream of the suction slot resulting in higher recovery pressure values at the trailing edge. At the design conditions of M = 0.7 and α = 0˚, a net profile drag reduction of 10.70% and an increase in the lift-to-drag ratio of 14.68% were observed when compared to no-suction conditions. Velocity flow field contours obtained from the PIV data showed an increase in the wake velocity magnitude for all Mach numbers at α = 0˚, displaying excellent agreement for the drag data at these conditions. Surface-oil flow visualization experiments revealed that the airfoil experienced extensive laminar flow runs regardless of suction application due to the low-Reynolds number test condition. The laminar flow was found to be shock limited followed by a laminar separation bubble in most cases. From the Schlieren experiments, a characteristic frequency of 22.38 Hz for the shock oscillatory process was identified at the design conditions which also was observed to stabilize under the influence of suction. In general, the improvements in aerodynamic efficiency and stability of the shock resulting from suction were observed to be greatest at higher angles of attack where the boundary layer was subjected to stronger-unforced pressure gradients.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2019-08-22 without embargo terms","The student, Armando Collazo Garcia III, accepted the attached license on 2019-04-23 at 13:49.","The student, Armando Collazo Garcia III, submitted this Thesis for approval on 2019-04-23 at 14:04.","This Thesis was approved for publication on 2019-04-23 at 16:59.","DSpace SAF Submission Ingestion Package generated from Vireo submission #13843 on 2019-08-22 at 14:46:06","Made available in DSpace on 2019-08-23T20:01:14Z (GMT). No. of bitstreams: 2 COLLAZOGARCIAIII-THESIS-2019.pdf: 63832821 bytes, checksum: 51e298f612c1afb17a62c0c2e38eeaa5 (MD5) LICENSE.txt: 4219 bytes, checksum: 8fc6e212bde6e99a4489a0ec696a9f34 (MD5) Previous issue date: 2019-04-23"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Aerodynamic characterization of a Griffith-type transonic, laminar-flow airfoil"]}]}],"canonical_facts":{"dc:contributor":["Ansell, Phillip J."],"dc:creator":["Collazo Garcia III, Armando Rafael"],"dc:date":["2019-08-23T20:01:14Z","2019-04-23","2019-05"],"dc:description":["An experimental investigation was conducted at the University of Illinois’ Transonic Wind Tunnel Facility on a Griffith-type transonic airfoil to evaluate the effectiveness of its laminar flow qualities and boundary-layer flow-control characteristics in the transonic regime. Airfoil surface and wake pressure data were acquired to characterize the aerodynamic performance across a range of α = -2˚ to 2˚ and M = 0.3 to 0.7. In addition, surface-oil flow visualization, PIV, and Schlieren imaging were performed to identify the suction influence on boundary-layer transition, momemtum deficit alleviation in the wake, and stability of transonic shocks. It was observed from the pressure distributions that the flow control application had a beneficial influence, allowing for a more aggressive pressure recovery downstream of the suction slot resulting in higher recovery pressure values at the trailing edge. At the design conditions of M = 0.7 and α = 0˚, a net profile drag reduction of 10.70% and an increase in the lift-to-drag ratio of 14.68% were observed when compared to no-suction conditions. Velocity flow field contours obtained from the PIV data showed an increase in the wake velocity magnitude for all Mach numbers at α = 0˚, displaying excellent agreement for the drag data at these conditions. Surface-oil flow visualization experiments revealed that the airfoil experienced extensive laminar flow runs regardless of suction application due to the low-Reynolds number test condition. The laminar flow was found to be shock limited followed by a laminar separation bubble in most cases. From the Schlieren experiments, a characteristic frequency of 22.38 Hz for the shock oscillatory process was identified at the design conditions which also was observed to stabilize under the influence of suction. In general, the improvements in aerodynamic efficiency and stability of the shock resulting from suction were observed to be greatest at higher angles of attack where the boundary layer was subjected to stronger-unforced pressure gradients.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2019-08-22 without embargo terms","The student, Armando Collazo Garcia III, accepted the attached license on 2019-04-23 at 13:49.","The student, Armando Collazo Garcia III, submitted this Thesis for approval on 2019-04-23 at 14:04.","This Thesis was approved for publication on 2019-04-23 at 16:59.","DSpace SAF Submission Ingestion Package generated from Vireo submission #13843 on 2019-08-22 at 14:46:06","Made available in DSpace on 2019-08-23T20:01:14Z (GMT). No. of bitstreams: 2 COLLAZOGARCIAIII-THESIS-2019.pdf: 63832821 bytes, checksum: 51e298f612c1afb17a62c0c2e38eeaa5 (MD5) LICENSE.txt: 4219 bytes, checksum: 8fc6e212bde6e99a4489a0ec696a9f34 (MD5) Previous issue date: 2019-04-23"],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/104909"],"dc:language":["en"],"dc:rights":["© 2019 by Armando R. Collazo Garcia III. All rights reserved."],"dc:subject":["transonic, laminar flow, flow control, airfoil, wind tunnel"],"dc:title":["Aerodynamic characterization of a Griffith-type transonic, laminar-flow airfoil"],"dc:type":["text"],"thesis:degree_discipline":["Aerospace Engineering"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:42Z"}