71th Annual Meeting of the APS Division of Fluid Dynamics (November 18, 2018 — November 20, 2018)

P0011: Chaotic Manifolds behind a Flapping Foil

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Authors

• CHANDAN BOSE, Ph.D. Scholar, Dept. of Applied Mechanics, IIT Madras, Chennai 600036, India.
• SAYAN GUPTA, Professor, Dept. of Applied Mechanics, IIT Madras, Chennai 600036, India.
• SUNETRA SARKAR, Professor, Dept. of Aerospace Engineering, IIT Madras, Chennai 600036, India.

DOI: https://doi.org/10.1103/APS.DFD.2018.GFM.P0011

Natural flyers flap their wings periodically to generate desired aerodynamic loads to fly by leaving a variety of wake patterns in the trail. The nature of these vortex shedding patterns holds the key to the aerodynamic load generation. The manifestation of chaos in the flow-field behind periodically flapping foils is an interesting phenomenon which, in turn, results in chaotic force generation. The leading-edge vortex is found to be the primary trigger behind the transition from order to chaos in the flow topology. Even a small erratic behavior in the leading-edge vortex could spell a complete eventual breakdown of a regular wake, which is sustained by the frequent and spontaneous formation of the vortex couples and the subsequent vortex interactions.