{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/21683"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/21683","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Aerodynamics of a chined forebody oscillating in pitch","abstract":"A low-speed experimental study of the effects of an oscillatory pitching motion on the flowfield of a chined forebody has been performed. These tests were conducted in the University of Illinois low-speed (0-240 ft/sec), low-turbulence ($<$0.1%), 3 by 4 ft, open circuit wind tunnel. The high fidelity, NC machined aluminum model was sting mounted and oscillated sinusoidally in pitch from 0$\\sp\\circ$ to 52$\\sp\\circ$ angle of attack without sideslip. The effects of reduced frequency as well as free-stream Reynolds number were investigated by running a range of tunnel velocity/model oscillation frequency combinations. Reynolds numbers, based on the 3-inch base diameter of the forebody, of 1.4 x 10$\\sp5$ to 2.8 x 10$\\sp5$ were tested. The experiments cover a range of oscillation frequencies from 0 to 1 Hz, corresponding to reduced frequencies, based on the 10.5-inch length, of 0 to 0.0275. Surface pressures were measured at all conditions using an array of 91 static pressure taps. Normal force and pitching moment were determined by integrating these data. Surface oil and smoke flow visualization were utilized to determine the vortex system and help interpret the surface pressure data.","abstract_html":"A low-speed experimental study of the effects of an oscillatory pitching motion on the flowfield of a chined forebody has been performed. These tests were conducted in the University of Illinois low-speed (0-240 ft/sec), low-turbulence ($&lt;$0.1%), 3 by 4 ft, open circuit wind tunnel. The high fidelity, NC machined aluminum model was sting mounted and oscillated sinusoidally in pitch from 0$\\sp\\circ$ to 52$\\sp\\circ$ angle of attack without sideslip. The effects of reduced frequency as well as free-stream Reynolds number were investigated by running a range of tunnel velocity/model oscillation frequency combinations. Reynolds numbers, based on the 3-inch base diameter of the forebody, of 1.4 x 10$\\sp5$ to 2.8 x 10$\\sp5$ were tested. The experiments cover a range of oscillation frequencies from 0 to 1 Hz, corresponding to reduced frequencies, based on the 10.5-inch length, of 0 to 0.0275. Surface pressures were measured at all conditions using an array of 91 static pressure taps. Normal force and pitching moment were determined by integrating these data. Surface oil and smoke flow visualization were utilized to determine the vortex system and help interpret the surface pressure data.","abstract_has_math":true,"creators":["Mange, Richard Lewis"],"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":2011,"date_issued":"2011-05-07T13:16:01Z","date_published":"2011-05-07T13:16:01Z","updated_at":"2026-07-22T22:25:18Z","subjects":["Engineering, Aerospace","Engineering, Mechanical"],"languages":["eng"],"rights":["Copyright 1996 Mange, Richard Lewis"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9625163","(UMI)AAI9625163"],"render_values":[{"text":"AAI9625163","href":null,"code":true},{"text":"(UMI)AAI9625163","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/21683","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":["Mange, Richard Lewis"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T13:16:01Z","10000-01-01","1996"]},{"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","Engineering, Mechanical"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1996 Mange, Richard Lewis"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9625163","(UMI)AAI9625163","http://hdl.handle.net/2142/21683"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["A low-speed experimental study of the effects of an oscillatory pitching motion on the flowfield of a chined forebody has been performed. These tests were conducted in the University of Illinois low-speed (0-240 ft/sec), low-turbulence ($<$0.1%), 3 by 4 ft, open circuit wind tunnel. The high fidelity, NC machined aluminum model was sting mounted and oscillated sinusoidally in pitch from 0$\\sp\\circ$ to 52$\\sp\\circ$ angle of attack without sideslip. The effects of reduced frequency as well as free-stream Reynolds number were investigated by running a range of tunnel velocity/model oscillation frequency combinations. Reynolds numbers, based on the 3-inch base diameter of the forebody, of 1.4 x 10$\\sp5$ to 2.8 x 10$\\sp5$ were tested. The experiments cover a range of oscillation frequencies from 0 to 1 Hz, corresponding to reduced frequencies, based on the 10.5-inch length, of 0 to 0.0275. Surface pressures were measured at all conditions using an array of 91 static pressure taps. Normal force and pitching moment were determined by integrating these data. Surface oil and smoke flow visualization were utilized to determine the vortex system and help interpret the surface pressure data.","Steady flow visualization revealed the importance of secondary boundary-layer separation on the leeward surface of the chined forebody. This separation was caused by a steep spanwise surface pressure gradient between the chine edge and the suction pressure peak associated with the primary vortex. Surface static pressure data indicated a hysteresis effect in the unsteady flowfield. Leeward surface static suction pressures built-up at lower angles-of-attack in the dynamic upstroke than in the steady case. The opposite was true in the dynamic downstroke. This hysteresis in leeward surface static pressures also resulted in a hysteresis in secondary boundary-layer separation, secondary vortex formation and the integrated forces and moments. These data showed increased lift in the upstroke and decreased lift in the downstroke, with negligible effects on the center-of-pressure.","Made available in DSpace on 2011-05-07T13:16:01Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9625163.pdf: 11702031 bytes, checksum: 6bd809b375686b3cf17da90e07e80787 (MD5) Previous issue date: 1996","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:52:30Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:24:11-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["Aerodynamics of a chined forebody oscillating in pitch"]}]}],"canonical_facts":{"dc:contributor":["Bragg, Michael B."],"dc:creator":["Mange, Richard Lewis"],"dc:date":["2011-05-07T13:16:01Z","10000-01-01","1996"],"dc:description":["A low-speed experimental study of the effects of an oscillatory pitching motion on the flowfield of a chined forebody has been performed. These tests were conducted in the University of Illinois low-speed (0-240 ft/sec), low-turbulence ($<$0.1%), 3 by 4 ft, open circuit wind tunnel. The high fidelity, NC machined aluminum model was sting mounted and oscillated sinusoidally in pitch from 0$\\sp\\circ$ to 52$\\sp\\circ$ angle of attack without sideslip. The effects of reduced frequency as well as free-stream Reynolds number were investigated by running a range of tunnel velocity/model oscillation frequency combinations. Reynolds numbers, based on the 3-inch base diameter of the forebody, of 1.4 x 10$\\sp5$ to 2.8 x 10$\\sp5$ were tested. The experiments cover a range of oscillation frequencies from 0 to 1 Hz, corresponding to reduced frequencies, based on the 10.5-inch length, of 0 to 0.0275. Surface pressures were measured at all conditions using an array of 91 static pressure taps. Normal force and pitching moment were determined by integrating these data. Surface oil and smoke flow visualization were utilized to determine the vortex system and help interpret the surface pressure data.","Steady flow visualization revealed the importance of secondary boundary-layer separation on the leeward surface of the chined forebody. This separation was caused by a steep spanwise surface pressure gradient between the chine edge and the suction pressure peak associated with the primary vortex. Surface static pressure data indicated a hysteresis effect in the unsteady flowfield. Leeward surface static suction pressures built-up at lower angles-of-attack in the dynamic upstroke than in the steady case. The opposite was true in the dynamic downstroke. This hysteresis in leeward surface static pressures also resulted in a hysteresis in secondary boundary-layer separation, secondary vortex formation and the integrated forces and moments. These data showed increased lift in the upstroke and decreased lift in the downstroke, with negligible effects on the center-of-pressure.","Made available in DSpace on 2011-05-07T13:16:01Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9625163.pdf: 11702031 bytes, checksum: 6bd809b375686b3cf17da90e07e80787 (MD5) Previous issue date: 1996","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:52:30Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:24:11-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"],"dc:identifier":["AAI9625163","(UMI)AAI9625163","http://hdl.handle.net/2142/21683"],"dc:language":["eng"],"dc:rights":["Copyright 1996 Mange, Richard Lewis"],"dc:subject":["Engineering, Aerospace","Engineering, Mechanical"],"dc:title":["Aerodynamics of a chined forebody oscillating in pitch"],"dc:type":["text"],"thesis:degree_discipline":["Aerospace Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:18Z"}