Abstract
The present study numerically investigated fluid-physical aspects of the autorotative flight of real maple seeds. The flow field and the motion characteristics of the autorotating maple seed were calculated by simultaneously solving the Navier–Stokes equations for the flow field around the seed and its 6-degree-of-freedom (6DOF) motion. The 6DOF simulation of the autorotative flight of the sample maple seed showed that the seed initially experienced a free-fall and a transient period of motion when all motion parameters of the autorotative flight (spinning rate, descent velocity, coning angle, and pitch angle) fluctuated. The sample maple seed then obtained a high spinning rate within a few seconds and entered into a stable autorotation. The motion parameters at the stable period of the autorotative flight predicted by the 6DOF simulation agreed reasonably well with those measured experimentally for maple seeds of same species and similar geometry. The lift was concentrated at the outer span region of the seed, whereas the drag was distributed relatively evenly over the whole span of the seed. The accelerating spinning moment was produced by the mid-span region of the seed. The flow analysis showed that a compact and attached leading edge vortex (LEV) was developed around the seed, and this LEV was possible by the spanwise transport of vorticity and the consequent spanwise spiraling flow. The compact and attached LEV caused a suction pressure distribution on the leeward surface of the seed, which created the high lift and spinning moment for the autorotative flight of the maple seed.
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References
Arranz G, Moriche M, Uhlmann M, Flores O, Garcia-Villalba M (2018) Kinematics and dynamics of the auto-rotation of a model winged seed. Bioinspiration Biomim 13(036011). https://doi.org/10.1088/1748-3190/aab144
Azuma A, Yasuda K (1989) Flight performance of rotary seeds. J Theor Biol 138:23–53. https://doi.org/10.1016/S0022-5193(89)80176-6
Azzam T, Belmerabet T, Mekadem M, Djellal S, Hanchi S (2011) Numerical simulation of the flow around the helicopter blade in hover using the MRF method and turbulence models. WIT Trans Built Environ 115:307–315. https://doi.org/10.2495/FSI110261
Birch JM, Dickinson MH (2001) Spanwise flow and the attachment of the leading-edge vortex on insect wings. Nature 412:729–733. https://doi.org/10.1038/35089071
Birch JM, Dickson WB, Dickinson MH (2004) Force production and flow structure of the leading edge vortex on flapping wings at high and low Reynolds numbers. J Exp Biol 207:1063–1072. https://doi.org/10.1242/jeb.00848
Ellington CP, van den Berg C, Willmott AP, Thomas ALR (1996) Leading-edge vortices in insect flight. Nature 384:626–630. https://doi.org/10.1038/384626a0
Lee I, Choi H (2017) Flight of a falling maple seed. Phys Rev Fluids 2 (090511). https://doi.org/10.1103/PhysRevFluids.2.090511
Lee E, Lee S (2016) Effect of initial attitude on autorotation flight of maple samaras (Acer palmatum). J Mech Sci Technol 30:741–747. https://doi.org/10.1007/s12206-016-0129-2
Lee SJ, Lee EJ, Sohn MH (2014) Mechanism of autorotation flight of maple samaras (Acer palmatum). Exp Fluids 55:1–9. https://doi.org/10.1007/s00348-014-1718-4
Lentink D, Dickson WB, van Leeuwen JL, Dickinson MH (2009) Leading-edge vortices elevate lift of autorotating plant seeds. Science 324:1438–1440. https://doi.org/10.1126/science.1174196
Minami S, Azuma A (2003) Various flying modes of wind-dispersal seeds. J Theor Biol 225:1–14. https://doi.org/10.1016/s0022-5193(03)00216-9
Norberg R (1973) Autorotation, self-stability, and structure of single-winged fruits and seeds (samaras) with comparative remarks on animal flight. Biol Rev 48:561–596. https://doi.org/10.1111/j.1469-185X.1973.tb01569.x
Seter D, Rosen A (1992) Study of the vertical autorotation of a single-winged samara. Biol Rev 67:175–197. https://doi.org/10.1115/1.2897683
Shyy W, Liu H (2007) Flapping wings and aerodynamic lift: the role of leading-edge vortices. AIAA J 45:2817–2819. https://doi.org/10.2514/1.33205
Varshney K, Chang S, Wang ZJ (2012) The kinematics of falling maple seeds and the initial transition to a helical motion. Nonlinearity 25:C1–C8. https://doi.org/10.1088/0951-7715/25/1/C1
Yasuda K, Azuma A (1997) The autorotation boundary in the flight of samaras. J Theor Biol 185:313–320. https://doi.org/10.1006/jtbi.1996.0299
Acknowledgements
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science (NRF-2016R1A2B1015783), and this work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIT) (No. 2018R1C1B5086435).
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MHS was involved in methodology, writing—review & editing, supervision, and funding acquisition. DKI was involved in software, validation, visualization, and writing—review & editing.
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Sohn, M.H., Im, D.K. Flight characteristics and flow structure of the autorotating maple seeds. J Vis 25, 483–500 (2022). https://doi.org/10.1007/s12650-021-00812-9
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DOI: https://doi.org/10.1007/s12650-021-00812-9