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Flow Structure and Force Generation on Flapping Wings at Low Reynolds Numbers Relevant to the Flight of Tiny Insects

Santhanakrishnan, Arvind and Jones, Shannon K. and Dickson, William B. and Peek, Martin and Kasoju, Vishwa T. and Dickinson, Michael H. and Miller, Laura A. (2018) Flow Structure and Force Generation on Flapping Wings at Low Reynolds Numbers Relevant to the Flight of Tiny Insects. Fluids, 3 (3). Art. No. 45. ISSN 2311-5521. doi:10.3390/fluids3030045.

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In contrast to larger species, little is known about the flight of the smallest flying insects, such as thrips and fairyflies. These tiny animals range from 300 to 1000 microns in length and fly at Reynolds numbers ranging from about 4 to 60. Previous work with numerical and physical models have shown that the aerodynamics of these diminutive insects is significantly different from that of larger animals, but most of these studies have relied on two-dimensional approximations. There can, however, be significant differences between two- and three-dimensional flows, as has been found for larger insects. To better understand the flight of the smallest insects, we have performed a systematic study of the forces and flow structures around a three-dimensional revolving elliptical wing. We used both a dynamically scaled physical model and a three-dimensional computational model at Reynolds numbers ranging from 1 to 130 and angles of attacks ranging from 0° to 90°. The results of the physical and computational models were in good agreement and showed that dimensionless drag, aerodynamic efficiency, and spanwise flow all decrease with decreasing Reynolds number. In addition, both the leading and trailing edge vortices remain attached to the wing over the scales relevant to the smallest flying insects. Overall, these observations suggest that there are drastic differences in the aerodynamics of flight at the scale of the smallest flying animals.

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Dickinson, Michael H.0000-0002-8587-9936
Additional Information:© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( Received: 12 May 2018; Accepted: 13 June 2018; Published: 22 June 2018. We would like to thank Charles Peskin and Boyce Griffith for their advice on the numerical simulations and the use of IBAMR. We would also like to thank Ty Hedrick for his continued support and assistance with filming thrips and other tiny insects. This research was funded by an NSF (IBN-0217229) and DARPA (N00014-98-1-0855) grants to M.H.D, NSF (CBET-1511427) to L.A.M, NSF (CBET-1512071) to A.S., a National Science Foundation Graduate Research Fellowship (NSF GRFP Grant No. DGE-1144081) to S.K.J., and a graduate fellowship from the Statistical and Applied Mathematics Institute to S.K.J. Author Contributions: Conceptualization, L.A.M. and M.H.D.; Methodology, M.H.D., W.B.D., A.S. and L.A.M.; Software, L.A.M., W.B.D., and S.K.J.; Validation S.K.J. and A.S.; Formal Analysis, A.S. and S.K.J.; Investigation, W.B.D., M.P., A.S., V.T.K. and S.K.J.; Resources, M.H.D. and L.A.M.; Data Curation, A.S., V.T.K. and S.K.J.; Writing-Original Draft Preparation, L.A.M., A.S. and S.K.J.; Writing-Review & Editing, L.A.M., M.H.D., S.K.J., and A.S.; Visualization, A.S. and S.K.J.; Supervision, L.A.M. and M.H.D.; Project Administration, L.A.M. and M.H.D.; Funding Acquisition, L.A.M. and M.H.D. The authors declare no conflict of interest.
Funding AgencyGrant Number
Defense Advanced Research Projects Agency (DARPA)N00014-98-1-0855
NSF Graduate Research FellowshipDGE-1144081
Statistical and Applied Mathematics InstituteUNSPECIFIED
Subject Keywords:insect flight; aerodynamics; low Reynolds number; flow visualization; immersed boundary method
Issue or Number:3
Record Number:CaltechAUTHORS:20190129-073741342
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Official Citation:Santhanakrishnan, A.; Jones, S.K.; Dickson, W.B.; Peek, M.; Kasoju, V.T.; Dickinson, M.H.; Miller, L.A. Flow Structure and Force Generation on Flapping Wings at Low Reynolds Numbers Relevant to the Flight of Tiny Insects. Fluids 2018, 3, 45; doi: 10.3390/fluids3030045
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:92506
Deposited By: Tony Diaz
Deposited On:29 Jan 2019 16:00
Last Modified:16 Nov 2021 03:51

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