Wave-riding and wave-passing by ducklings in formation swimming
Yuan, Zhi-Ming and Chen, Minglu and Jia, Laibing and Ji, Chunyan and Incecik, Atilla (2021) Wave-riding and wave-passing by ducklings in formation swimming. Journal of Fluid Mechanics, 928. R2. ISSN 1469-7645 (https://doi.org/10.1017/jfm.2021.820)
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Abstract
It has been commonly observed on open waters that ducklings/goslings follow their mothers in a highly organized formation. The questions arise: (1) why are they swimming in formation? (2) what is the best swimming formation? (3) how much energy can be preserved by each individual in formation swimming? To address these questions, we established a simplified mathematical and numerical model and calculated the wave drag on a group of waterfowl in a swimming formation. We observed two new and interesting findings: wave-riding and wave-passing. By riding the waves generated by a mother duck, a trailing duckling can obtain a significant wave-drag reduction. When a duckling swims at the ‘sweet point’ behind its mother, a destructive wave interference phenomenon occurs and the wave drag of the duckling turns positive, pushing the duckling forward. More interestingly, this wave-riding benefit could be sustained by the rest of the ducklings in a single-file line formation. Starting from the third one in a queue, the wave drag of individuals gradually tended towards zero, and a delicate dynamic equilibrium was achieved. Each individual under that equilibrium acted as a wave passer, passing the waves’ energy to its trailing one without any energy losses. Wave-riding and wave-passing are probably the principal reasons for the evolution of swimming formation by waterfowl. This study is the first to reveal the reasons why the formation movement of waterfowl can preserve individuals’ energy expenditure. Our calculations provide new insights into the mechanisms of formation swimming.
ORCID iDs
Yuan, Zhi-Ming ORCID: https://orcid.org/0000-0001-9908-1813, Chen, Minglu, Jia, Laibing ORCID: https://orcid.org/0000-0003-1327-5516, Ji, Chunyan and Incecik, Atilla;-
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Item type: Article ID code: 78035 Dates: DateEvent10 December 2021Published5 October 2021Published Online17 September 2021AcceptedSubjects: Technology > Hydraulic engineering. Ocean engineering Department: Faculty of Engineering > Naval Architecture, Ocean & Marine Engineering
Faculty of EngineeringDepositing user: Pure Administrator Date deposited: 06 Oct 2021 14:00 Last modified: 01 Sep 2024 01:31 URI: https://strathprints.strath.ac.uk/id/eprint/78035