{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,22]],"date-time":"2025-10-22T18:13:50Z","timestamp":1761156830141,"version":"build-2065373602"},"reference-count":28,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2020,1,29]],"date-time":"2020-01-29T00:00:00Z","timestamp":1580256000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["51806181"],"award-info":[{"award-number":["51806181"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Rotor Aerodynamics Key Laboratory","award":["RAL20180202-2"],"award-info":[{"award-number":["RAL20180202-2"]}]},{"name":"the open fund from State Key Laboratory of Aerodynamics","award":["SKLA20180104"],"award-info":[{"award-number":["SKLA20180104"]}]},{"name":"Sichuan Provincial Department of Education","award":["18ZA0458"],"award-info":[{"award-number":["18ZA0458"]}]},{"name":"Key Laboratory of Aeroengine Pneumatic and Thermal Defence Science and Technology","award":["6142702180101"],"award-info":[{"award-number":["6142702180101"]}]},{"name":"&quot;Young Scholars&quot; Program of Xihua University","award":["17"],"award-info":[{"award-number":["17"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>The rotorcraft blade tip vortex rolled up by the blade tip when the rotor rotates at high speed will produce a complex induced velocity field, which will have an important impact on the aerodynamic load and performance of the rotor. For this reason, this paper carries out the research on the identification of blade tip vortex and the motion characteristics of the vortex. Through the time-resolved particle image velocimetry (TR-PIV) experiment, the flow field of the rotor at a fixed rotate speed (2100 r\/min) with a collective pitch of 6\u00b0 and 9\u00b0 was obtained. Based on the vorticity field, Q criterion, and \u03a9 criterion, the research on vortex identification and vortex motion characteristics are realized. The results show that with the increase of blade motion azimuth, the radial position of blade tip vortex gradually contracts inward and the axial position moves downward in hovering state. As the collective pitch of the rotor increases, the radial contraction becomes more obvious, and the axial displacement increases, at the same time, the blade tip vortex intensity increases. Comparative study results show that different vortex identification methods have obtained certain deviations in the vortex center. Compared with other vortex identification methods, the \u03a9 criterion method has a smaller deviation and can accurately identify the vortex core radius and vortex boundary.<\/jats:p>","DOI":"10.3390\/sym12020196","type":"journal-article","created":{"date-parts":[[2020,1,29]],"date-time":"2020-01-29T10:51:07Z","timestamp":1580295067000},"page":"196","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Research on Rotorcraft Blade Tip Vortex Identification and Motion Characteristics in Hovering State"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2282-8987","authenticated-orcid":false,"given":"Hai","family":"Du","sequence":"first","affiliation":[{"name":"School of Energy and Power Engineering, Xihua University, Chengdu 610039, China"},{"name":"Key Laboratory of Fluid and Power Machinery, Ministry of Education, Xihua University, Chengdu 610039, China"},{"name":"Rotor Aerodynamics Key Laboratory, China Aerodynamics Research and Development Center, Mianyang 621000, China"}]},{"given":"Wenjie","family":"Kong","sequence":"additional","affiliation":[{"name":"School of Energy and Power Engineering, Xihua University, Chengdu 610039, China"}]},{"given":"Yan","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Energy and Power Engineering, Xihua University, Chengdu 610039, China"}]},{"given":"Wenjing","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Energy and Power Engineering, Xihua University, Chengdu 610039, China"}]},{"given":"Mingqi","family":"Huang","sequence":"additional","affiliation":[{"name":"Rotor Aerodynamics Key Laboratory, China Aerodynamics Research and Development Center, Mianyang 621000, China"}]},{"given":"Weiguo","family":"Zhang","sequence":"additional","affiliation":[{"name":"Rotor Aerodynamics Key Laboratory, China Aerodynamics Research and Development Center, Mianyang 621000, China"}]},{"given":"Min","family":"Tang","sequence":"additional","affiliation":[{"name":"Rotor Aerodynamics Key Laboratory, China Aerodynamics Research and Development Center, Mianyang 621000, China"}]}],"member":"1968","published-online":{"date-parts":[[2020,1,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Ebrahimpour, M., Shafaghat, R., Alamian, R., and Safdari Shadloo, M. 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