Flapping Wing Aerodynamics

Dynamic analysis of near-field and far-field wake patterns

The nature of wake patterns behind flapping wings holds the key to aerodynamic load generation. The manifestation of chaos in the flow-field behind periodically flapping foils is an interesting phenomenon that, 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, sustained by the frequent and spontaneous formation of the vortex couples and the subsequent vortex interactions. A dynamic interlinking is established between the near and far-field wake in terms of the underlying transition routes to chaos. The Jet-switching phenomenon is found to play a crucial role as the precursor to chaos.

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2. Bose, C., & Sarkar, S. (2018). Investigating chaotic wake dynamics past a flapping airfoil and the role of vortex interactions behind the chaotic transition. Physics of Fluids, 30(4), 047101.
3. Majumdar, D., Bose, C., & Sarkar, S. (2020). Capturing the dynamical transitions in the flow-field of a flapping foil using Immersed Boundary Method. Journal of Fluids and Structures, 95, 102999.
4. Majumdar, D., Bose, C., & Sarkar, S. (2020). Effect of gusty inflow on the jet-switching characteristics of a plunging foil. Physics of Fluids, 32(11), 117105.
5. Bose, C., Gupta, S., & Sarkar, S. (2021). Dynamic interlinking between near-and far-field wakes behind a pitching–heaving airfoil. Journal of Fluid Mechanics, 911.