Shedding of vortices is a common phenomenon in the atmosphere over a wide range of spatial and temporal scales. However, it is unclear how these vortices of varying scales affect the flight performance of flying animals. In order to examine these interactions, we trained seven hawkmoths (Manduca sexta) (wingspan ~9 cm) to fly and feed in a wind tunnel under steady flow (controls) and in the von...

Numerical simulations are employed to study the hydrodynamics of self-propelled thunniform swimming. The swimmer is modeled as a tuna-like flexible body undulating with kinematics of thunniform type. The wake evolution follows the vortex structures arranged nearly vertical to the forward direction, vortex dipole formation resulting in the propulsion motion, and finally a reverse Kármán vortex s...

1 Lagrangian analysis is capable of revealing the underlying structure and complex phenomena in unsteady flows. We present Particle-Image Velocimetry measurements of the wake of a cylinder undergoing streamwise vortex-induced vibrations and calculate the Finite-Time Lyapunov Exponents (FTLE) in backward-and forward-time. The FTLE fields are compared to the phase-averaged vorticity fields for th...

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