{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/99524"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/99524","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Wind tunnel study of wind farms with alternating 2- and 3-bladed wind turbines","abstract":"With offshore wind farms gaining substantial momentum in recent years, 2-bladed turbines (2BT) are increasingly becoming a viable alternative to 3-bladed counterparts (3BT). In this wind tunnel study, model wind farms with alternating rows of 3BT and 2BT were explored for potential benefits associated with enhanced momentum available within the arrays and reduced costs due to the reduction of blades. Two arrays of aligned turbines with streamwise separation of five and ten rotor diameter d (Sx = Δx/d =5 and 10) were operated in a turbulent boundary layer flow. They shared the same transverse turbine spacing of Sy = Δy/d =2.5. High-resolution velocity measurements were made with hotwire anemometry at various locations in the wake and the power output of turbines was measured simultaneously. Comparison of the flow between an array with only 3BT and that with alternating 2BT and 3BT shows enhanced mean velocity and reduced turbulence levels for the latter in Sx = 5 case. The pre-multiplied spectra of the flow at selected locations within the wind farm suggest that large energetic structures at top-tip and hub height are dampened by 2BT, with the potential to reduce turbulent loading on downwind turbines. Although the reduced mixing at top tip height behind 2BT causes the momentum recovery rate to diminish, the available momentum at downstream turbine is still higher than corresponding 3BT in the Sx = 5 case. Overall performance gain from marginally enhanced power statistics of 3BT operating in the wake of 2BT is offset by the diminished performance of 2BT inside the farm, resulting in comparable performance between the two configurations.","abstract_html":"With offshore wind farms gaining substantial momentum in recent years, 2-bladed turbines (2BT) are increasingly becoming a viable alternative to 3-bladed counterparts (3BT). In this wind tunnel study, model wind farms with alternating rows of 3BT and 2BT were explored for potential benefits associated with enhanced momentum available within the arrays and reduced costs due to the reduction of blades. Two arrays of aligned turbines with streamwise separation of five and ten rotor diameter d (Sx = Δx/d =5 and 10) were operated in a turbulent boundary layer flow. They shared the same transverse turbine spacing of Sy = Δy/d =2.5. High-resolution velocity measurements were made with hotwire anemometry at various locations in the wake and the power output of turbines was measured simultaneously. Comparison of the flow between an array with only 3BT and that with alternating 2BT and 3BT shows enhanced mean velocity and reduced turbulence levels for the latter in Sx = 5 case. The pre-multiplied spectra of the flow at selected locations within the wind farm suggest that large energetic structures at top-tip and hub height are dampened by 2BT, with the potential to reduce turbulent loading on downwind turbines. Although the reduced mixing at top tip height behind 2BT causes the momentum recovery rate to diminish, the available momentum at downstream turbine is still higher than corresponding 3BT in the Sx = 5 case. Overall performance gain from marginally enhanced power statistics of 3BT operating in the wake of 2BT is offset by the diminished performance of 2BT inside the farm, resulting in comparable performance between the two configurations.","abstract_has_math":false,"creators":["Hayat, Imran"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Aerospace Engineering","degree_department":null,"school":null,"contributors":["Chamorro, Leonardo P."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2018,"date_issued":"2018-03-13T17:35:53Z","date_published":"2018-03-13T17:35:53Z","updated_at":"2026-07-22T22:24:37Z","subjects":["Two-bladed turbine","Power optimization","Wind farm","Wake"],"languages":["en"],"rights":["Copyright 2017 Imran Hayat"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/99524","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Chamorro, Leonardo P."]},{"key":"dc:creator","label":"Author","values":["Hayat, Imran"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2018-03-13T17:35:53Z","2020-03-14T09:15:25Z","2017-12-11","2017-12"]},{"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":["Two-bladed turbine","Power optimization","Wind farm","Wake"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2017 Imran Hayat"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/99524"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["With offshore wind farms gaining substantial momentum in recent years, 2-bladed turbines (2BT) are increasingly becoming a viable alternative to 3-bladed counterparts (3BT). In this wind tunnel study, model wind farms with alternating rows of 3BT and 2BT were explored for potential benefits associated with enhanced momentum available within the arrays and reduced costs due to the reduction of blades. Two arrays of aligned turbines with streamwise separation of five and ten rotor diameter d (Sx = Δx/d =5 and 10) were operated in a turbulent boundary layer flow. They shared the same transverse turbine spacing of Sy = Δy/d =2.5. High-resolution velocity measurements were made with hotwire anemometry at various locations in the wake and the power output of turbines was measured simultaneously. Comparison of the flow between an array with only 3BT and that with alternating 2BT and 3BT shows enhanced mean velocity and reduced turbulence levels for the latter in Sx = 5 case. The pre-multiplied spectra of the flow at selected locations within the wind farm suggest that large energetic structures at top-tip and hub height are dampened by 2BT, with the potential to reduce turbulent loading on downwind turbines. Although the reduced mixing at top tip height behind 2BT causes the momentum recovery rate to diminish, the available momentum at downstream turbine is still higher than corresponding 3BT in the Sx = 5 case. Overall performance gain from marginally enhanced power statistics of 3BT operating in the wake of 2BT is offset by the diminished performance of 2BT inside the farm, resulting in comparable performance between the two configurations.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2019-12-01","The student, Imran Hayat, accepted the attached license on 2017-12-08 at 16:26.","The student, Imran Hayat, submitted this Thesis for approval on 2017-12-08 at 16:59.","This Thesis was approved for publication on 2017-12-11 at 16:23.","DSpace SAF Submission Ingestion Package generated from Vireo submission #11930 on 2018-03-13 at 10:38:04","Made available in DSpace on 2018-03-13T17:35:53Z (GMT). No. of bitstreams: 2 HAYAT-THESIS-2017.pdf: 5926360 bytes, checksum: aa4085400b32e02967d67c76546098bf (MD5) LICENSE.txt: 4208 bytes, checksum: fbc00b6a3319db257341ca270081bd8c (MD5) Previous issue date: 2017-12-11","Embargo set by: Seth Robbins for item 105493 Lift date: 2020-03-13T17:36:05Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited Restriction Lifted for Item 105493 on 2020-03-14T09:15:25Z."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Wind tunnel study of wind farms with alternating 2- and 3-bladed wind turbines"]}]}],"canonical_facts":{"dc:contributor":["Chamorro, Leonardo P."],"dc:creator":["Hayat, Imran"],"dc:date":["2018-03-13T17:35:53Z","2020-03-14T09:15:25Z","2017-12-11","2017-12"],"dc:description":["With offshore wind farms gaining substantial momentum in recent years, 2-bladed turbines (2BT) are increasingly becoming a viable alternative to 3-bladed counterparts (3BT). In this wind tunnel study, model wind farms with alternating rows of 3BT and 2BT were explored for potential benefits associated with enhanced momentum available within the arrays and reduced costs due to the reduction of blades. Two arrays of aligned turbines with streamwise separation of five and ten rotor diameter d (Sx = Δx/d =5 and 10) were operated in a turbulent boundary layer flow. They shared the same transverse turbine spacing of Sy = Δy/d =2.5. High-resolution velocity measurements were made with hotwire anemometry at various locations in the wake and the power output of turbines was measured simultaneously. Comparison of the flow between an array with only 3BT and that with alternating 2BT and 3BT shows enhanced mean velocity and reduced turbulence levels for the latter in Sx = 5 case. The pre-multiplied spectra of the flow at selected locations within the wind farm suggest that large energetic structures at top-tip and hub height are dampened by 2BT, with the potential to reduce turbulent loading on downwind turbines. Although the reduced mixing at top tip height behind 2BT causes the momentum recovery rate to diminish, the available momentum at downstream turbine is still higher than corresponding 3BT in the Sx = 5 case. Overall performance gain from marginally enhanced power statistics of 3BT operating in the wake of 2BT is offset by the diminished performance of 2BT inside the farm, resulting in comparable performance between the two configurations.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2019-12-01","The student, Imran Hayat, accepted the attached license on 2017-12-08 at 16:26.","The student, Imran Hayat, submitted this Thesis for approval on 2017-12-08 at 16:59.","This Thesis was approved for publication on 2017-12-11 at 16:23.","DSpace SAF Submission Ingestion Package generated from Vireo submission #11930 on 2018-03-13 at 10:38:04","Made available in DSpace on 2018-03-13T17:35:53Z (GMT). No. of bitstreams: 2 HAYAT-THESIS-2017.pdf: 5926360 bytes, checksum: aa4085400b32e02967d67c76546098bf (MD5) LICENSE.txt: 4208 bytes, checksum: fbc00b6a3319db257341ca270081bd8c (MD5) Previous issue date: 2017-12-11","Embargo set by: Seth Robbins for item 105493 Lift date: 2020-03-13T17:36:05Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited Restriction Lifted for Item 105493 on 2020-03-14T09:15:25Z."],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/99524"],"dc:language":["en"],"dc:rights":["Copyright 2017 Imran Hayat"],"dc:subject":["Two-bladed turbine","Power optimization","Wind farm","Wake"],"dc:title":["Wind tunnel study of wind farms with alternating 2- and 3-bladed wind turbines"],"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":"2026-07-22T22:24:37Z"}