{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,18]],"date-time":"2026-01-18T03:00:12Z","timestamp":1768705212690,"version":"3.49.0"},"reference-count":21,"publisher":"Springer Science and Business Media LLC","issue":"3","license":[{"start":{"date-parts":[[2020,3,31]],"date-time":"2020-03-31T00:00:00Z","timestamp":1585612800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2020,3,31]],"date-time":"2020-03-31T00:00:00Z","timestamp":1585612800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["J Vis"],"published-print":{"date-parts":[[2020,6]]},"abstract":"<jats:sec><jats:title>Abstract<\/jats:title><jats:p>This experimental work studied the flow characteristics in the near wake region behind dual-rotor wind turbines using two-dimensional particle image velocimetry. Two auxiliary rotors of 50% and 80% scale of the main rotor were installed upwind and operated in counter-rotating condition, which are compared to the conventional single-rotor turbine. In all the three configurations, a constant Reynolds number<jats:inline-formula><jats:alternatives><jats:tex-math>$$9.5\\times 10^4$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mrow><mml:mn>9.5<\/mml:mn><mml:mo>\u00d7<\/mml:mo><mml:msup><mml:mn>10<\/mml:mn><mml:mn>4<\/mml:mn><\/mml:msup><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula>was applied, and all the rotors operated at a fixed tip speed ratio of 3.46. The mean and phase-averaged velocity fields were investigated together with the turbulence kinetic energy. It was found that the two auxiliary rotors do not result in a significantly different wake flow property. The configuration implementing the<jats:inline-formula><jats:alternatives><jats:tex-math>$$50\\%$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mrow><mml:mn>50<\/mml:mn><mml:mo>%<\/mml:mo><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula>auxiliary rotor sees a slightly better wake characteristics, in terms of weaker main rotor tip vortices and a counter-rotating swirling shear region at the mid-span behind the main rotor. The decay rates of the peak vorticity of the main rotor tip vortices and their circulation are found to follow an exponential manner.<\/jats:p><\/jats:sec><jats:sec><jats:title>Graphic abstract<\/jats:title><\/jats:sec>","DOI":"10.1007\/s12650-020-00643-0","type":"journal-article","created":{"date-parts":[[2020,3,31]],"date-time":"2020-03-31T10:02:58Z","timestamp":1585648978000},"page":"425-435","update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["A particle image velocimetry study of dual-rotor counter-rotating wind turbine near wake"],"prefix":"10.1007","volume":"23","author":[{"given":"Eloise O.","family":"Hollands","sequence":"first","affiliation":[]},{"given":"Chuangxin","family":"He","sequence":"additional","affiliation":[]},{"given":"Lian","family":"Gan","sequence":"additional","affiliation":[]}],"member":"297","published-online":{"date-parts":[[2020,3,31]]},"reference":[{"key":"643_CR1","doi-asserted-by":"crossref","unstructured":"Bartl J (2011) Wake measurements behind an array of two model wind turbines. 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