{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/85103"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/85103","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Iced Airfoil Separation Bubble Measurements by Particle Image Velocimetry","abstract":"Previous iced airfoil investigations have demonstrated somewhat reduced aerodynamic penalties resulting from a three-dimensional ice simulation, compared to those of a two-dimensional ice simulation of a representative cross section. Correspondingly, the current measurements revealed accelerated transition of the separated shear layer emanating from a three-dimensional ice simulation and therefore enhanced pressure recovery and reduced mean separation bubble length, each relative to the flowfield of a representative two-dimensional ice simulation. These effects appeared to result from the quasi-steady distribution of discrete, streamwise vortices which aided the turbulent entrainment of fluid from the recirculation region of the three-dimensional ice simulation separation bubble flowfield. These vortices were generated by a streamwise-vortex instability excited by roughness along the three-dimensional ice simulation and produced spanwise-cell structures throughout this flowfield, as well as significant spanwise variation in peak turbulence statistics. However, these variations were strongly correlated to the local degree of flowfield three-dimensionality observed from surface oil-flow visualization, indicating a three-dimensional relieving effect, such that measurements within a quasi-two-dimensional spanwise region were both qualitatively and quantitatively similar to those of the two-dimensional ice simulation separation bubble flowfield.","abstract_html":"Previous iced airfoil investigations have demonstrated somewhat reduced aerodynamic penalties resulting from a three-dimensional ice simulation, compared to those of a two-dimensional ice simulation of a representative cross section. Correspondingly, the current measurements revealed accelerated transition of the separated shear layer emanating from a three-dimensional ice simulation and therefore enhanced pressure recovery and reduced mean separation bubble length, each relative to the flowfield of a representative two-dimensional ice simulation. These effects appeared to result from the quasi-steady distribution of discrete, streamwise vortices which aided the turbulent entrainment of fluid from the recirculation region of the three-dimensional ice simulation separation bubble flowfield. These vortices were generated by a streamwise-vortex instability excited by roughness along the three-dimensional ice simulation and produced spanwise-cell structures throughout this flowfield, as well as significant spanwise variation in peak turbulence statistics. However, these variations were strongly correlated to the local degree of flowfield three-dimensionality observed from surface oil-flow visualization, indicating a three-dimensional relieving effect, such that measurements within a quasi-two-dimensional spanwise region were both qualitatively and quantitatively similar to those of the two-dimensional ice simulation separation bubble flowfield.","abstract_has_math":false,"creators":["Jacobs, Jason J."],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Aerospace Engineering","degree_department":null,"school":null,"contributors":["Bragg, Michael B."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-25T22:34:26Z","date_published":"2015-09-25T22:34:26Z","updated_at":"2026-07-22T22:26:24Z","subjects":["Engineering, Aerospace"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(MiAaPQ)AAI3290256"],"render_values":[{"text":"(MiAaPQ)AAI3290256","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/85103","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Bragg, Michael B."]},{"key":"dc:creator","label":"Author","values":["Jacobs, Jason J."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-09-25T22:34:26Z","10000-01-01","2007"]},{"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":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"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":["Engineering, Aerospace"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/85103","(MiAaPQ)AAI3290256"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Previous iced airfoil investigations have demonstrated somewhat reduced aerodynamic penalties resulting from a three-dimensional ice simulation, compared to those of a two-dimensional ice simulation of a representative cross section. Correspondingly, the current measurements revealed accelerated transition of the separated shear layer emanating from a three-dimensional ice simulation and therefore enhanced pressure recovery and reduced mean separation bubble length, each relative to the flowfield of a representative two-dimensional ice simulation. These effects appeared to result from the quasi-steady distribution of discrete, streamwise vortices which aided the turbulent entrainment of fluid from the recirculation region of the three-dimensional ice simulation separation bubble flowfield. These vortices were generated by a streamwise-vortex instability excited by roughness along the three-dimensional ice simulation and produced spanwise-cell structures throughout this flowfield, as well as significant spanwise variation in peak turbulence statistics. However, these variations were strongly correlated to the local degree of flowfield three-dimensionality observed from surface oil-flow visualization, indicating a three-dimensional relieving effect, such that measurements within a quasi-two-dimensional spanwise region were both qualitatively and quantitatively similar to those of the two-dimensional ice simulation separation bubble flowfield.","Made available in DSpace on 2015-09-25T22:34:26Z (GMT). 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However, these variations were strongly correlated to the local degree of flowfield three-dimensionality observed from surface oil-flow visualization, indicating a three-dimensional relieving effect, such that measurements within a quasi-two-dimensional spanwise region were both qualitatively and quantitatively similar to those of the two-dimensional ice simulation separation bubble flowfield.","Made available in DSpace on 2015-09-25T22:34:26Z (GMT). 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