{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/104908"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/104908","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"High lift configuration of a slotted natural laminar flow airfoil","abstract":"Experiments were performed on a slotted natural laminar flow airfoil, the S414. The slotted natural laminar flow airfoil concept was developed to satisfy design constraints of high maximum lift and low profile drag. A two-element natural laminar flow configuration allows the typical rapid trailing-edge pressure recovery associated with NLF airfoils to be greatly reduced on the fore element, allowing for laminar flow across the entire airfoil upper surface. The slot provides a favorable injection of momentum to the flow over the aft-element upper surface, improving lift generation. However, an unfortunate side effect of the S414 is an abrupt, leading-edge stall type. This investigation focused on the development of a high-lift configuration of the S414 by altering the position of the aft element in order to characterize the feasibility of utilizing the aft element as a high-lift device. Computational analysis was performed on the S414 to determine suitable aft-element positions for high lift. Two basic repositioning approaches were used; one that deflected the aft element to increase the airfoil camber while maintaining the slot width of the original airfoil, and one that targeted the utilization of the fore-element dumping velocity. In addition, a plain flap was incorporated into the aft element. Performance predictions for the new aft-element configurations were generated using the computational flow solver MSES, and four alternative aft-element riggings were selected for experimental testing. Tests were performed in the University of Illinois 2.8 ft × 4 ft wind tunnel at Re = 1.8 × 10^6, M = 0.18. Using knowledge gained from the experimental tests, a fifth, empirically-derived configuration was developed. Both computational and experimental results indicated that effective utilization of the fore-element dumping velocity results in the largest increase in Cl. Orienting the aft element such that the flow off the fore element was discharged into a region of low pressure over the aft-element upper surface reduced the pressure recovery requirements at the fore-element trailing edge, allowing for enhanced lift production. In addition, a momentum injection was provided to the flow over the aft-element upper surface, promoting increased lift generation by the aft element as well. These techniques coupled with the deflection of the aft-element plain flap resulted in a 34% increase in Cl,max.","abstract_html":"Experiments were performed on a slotted natural laminar flow airfoil, the S414. The slotted natural laminar flow airfoil concept was developed to satisfy design constraints of high maximum lift and low profile drag. A two-element natural laminar flow configuration allows the typical rapid trailing-edge pressure recovery associated with NLF airfoils to be greatly reduced on the fore element, allowing for laminar flow across the entire airfoil upper surface. The slot provides a favorable injection of momentum to the flow over the aft-element upper surface, improving lift generation. However, an unfortunate side effect of the S414 is an abrupt, leading-edge stall type. This investigation focused on the development of a high-lift configuration of the S414 by altering the position of the aft element in order to characterize the feasibility of utilizing the aft element as a high-lift device. Computational analysis was performed on the S414 to determine suitable aft-element positions for high lift. Two basic repositioning approaches were used; one that deflected the aft element to increase the airfoil camber while maintaining the slot width of the original airfoil, and one that targeted the utilization of the fore-element dumping velocity. In addition, a plain flap was incorporated into the aft element. Performance predictions for the new aft-element configurations were generated using the computational flow solver MSES, and four alternative aft-element riggings were selected for experimental testing. Tests were performed in the University of Illinois 2.8 ft × 4 ft wind tunnel at Re = 1.8 × 10^6, M = 0.18. Using knowledge gained from the experimental tests, a fifth, empirically-derived configuration was developed. Both computational and experimental results indicated that effective utilization of the fore-element dumping velocity results in the largest increase in Cl. Orienting the aft element such that the flow off the fore element was discharged into a region of low pressure over the aft-element upper surface reduced the pressure recovery requirements at the fore-element trailing edge, allowing for enhanced lift production. In addition, a momentum injection was provided to the flow over the aft-element upper surface, promoting increased lift generation by the aft element as well. These techniques coupled with the deflection of the aft-element plain flap resulted in a 34% increase in Cl,max.","abstract_has_math":false,"creators":["Twiss, Daniel C."],"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":["High Lift","Aerodynamics","MSES","Laminar Flow","Multi-Element Airfoil"],"languages":["en"],"rights":["Copyright 2019 by Daniel Twiss"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/104908","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":["Twiss, Daniel C."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2019-08-23T20:01:14Z","2019-04-24","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":["High Lift","Aerodynamics","MSES","Laminar Flow","Multi-Element Airfoil"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2019 by Daniel Twiss"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/104908"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Experiments were performed on a slotted natural laminar flow airfoil, the S414. The slotted natural laminar flow airfoil concept was developed to satisfy design constraints of high maximum lift and low profile drag. A two-element natural laminar flow configuration allows the typical rapid trailing-edge pressure recovery associated with NLF airfoils to be greatly reduced on the fore element, allowing for laminar flow across the entire airfoil upper surface. The slot provides a favorable injection of momentum to the flow over the aft-element upper surface, improving lift generation. However, an unfortunate side effect of the S414 is an abrupt, leading-edge stall type. This investigation focused on the development of a high-lift configuration of the S414 by altering the position of the aft element in order to characterize the feasibility of utilizing the aft element as a high-lift device. Computational analysis was performed on the S414 to determine suitable aft-element positions for high lift. Two basic repositioning approaches were used; one that deflected the aft element to increase the airfoil camber while maintaining the slot width of the original airfoil, and one that targeted the utilization of the fore-element dumping velocity. In addition, a plain flap was incorporated into the aft element. Performance predictions for the new aft-element configurations were generated using the computational flow solver MSES, and four alternative aft-element riggings were selected for experimental testing. Tests were performed in the University of Illinois 2.8 ft × 4 ft wind tunnel at Re = 1.8 × 10^6, M = 0.18. Using knowledge gained from the experimental tests, a fifth, empirically-derived configuration was developed. Both computational and experimental results indicated that effective utilization of the fore-element dumping velocity results in the largest increase in Cl. Orienting the aft element such that the flow off the fore element was discharged into a region of low pressure over the aft-element upper surface reduced the pressure recovery requirements at the fore-element trailing edge, allowing for enhanced lift production. In addition, a momentum injection was provided to the flow over the aft-element upper surface, promoting increased lift generation by the aft element as well. These techniques coupled with the deflection of the aft-element plain flap resulted in a 34% increase in Cl,max.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2019-08-22 without embargo terms","The student, Daniel Twiss, accepted the attached license on 2019-04-23 at 12:53.","The student, Daniel Twiss, submitted this Thesis for approval on 2019-04-23 at 13:19.","This Thesis was approved for publication on 2019-04-24 at 14:57.","DSpace SAF Submission Ingestion Package generated from Vireo submission #13842 on 2019-08-22 at 14:46:05","Made available in DSpace on 2019-08-23T20:01:14Z (GMT). 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A two-element natural laminar flow configuration allows the typical rapid trailing-edge pressure recovery associated with NLF airfoils to be greatly reduced on the fore element, allowing for laminar flow across the entire airfoil upper surface. The slot provides a favorable injection of momentum to the flow over the aft-element upper surface, improving lift generation. However, an unfortunate side effect of the S414 is an abrupt, leading-edge stall type. This investigation focused on the development of a high-lift configuration of the S414 by altering the position of the aft element in order to characterize the feasibility of utilizing the aft element as a high-lift device. Computational analysis was performed on the S414 to determine suitable aft-element positions for high lift. Two basic repositioning approaches were used; one that deflected the aft element to increase the airfoil camber while maintaining the slot width of the original airfoil, and one that targeted the utilization of the fore-element dumping velocity. In addition, a plain flap was incorporated into the aft element. Performance predictions for the new aft-element configurations were generated using the computational flow solver MSES, and four alternative aft-element riggings were selected for experimental testing. Tests were performed in the University of Illinois 2.8 ft × 4 ft wind tunnel at Re = 1.8 × 10^6, M = 0.18. Using knowledge gained from the experimental tests, a fifth, empirically-derived configuration was developed. Both computational and experimental results indicated that effective utilization of the fore-element dumping velocity results in the largest increase in Cl. Orienting the aft element such that the flow off the fore element was discharged into a region of low pressure over the aft-element upper surface reduced the pressure recovery requirements at the fore-element trailing edge, allowing for enhanced lift production. In addition, a momentum injection was provided to the flow over the aft-element upper surface, promoting increased lift generation by the aft element as well. These techniques coupled with the deflection of the aft-element plain flap resulted in a 34% increase in Cl,max.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2019-08-22 without embargo terms","The student, Daniel Twiss, accepted the attached license on 2019-04-23 at 12:53.","The student, Daniel Twiss, submitted this Thesis for approval on 2019-04-23 at 13:19.","This Thesis was approved for publication on 2019-04-24 at 14:57.","DSpace SAF Submission Ingestion Package generated from Vireo submission #13842 on 2019-08-22 at 14:46:05","Made available in DSpace on 2019-08-23T20:01:14Z (GMT). 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