Stabilizing effect of flexibility in the wake of a flapping foil

Abstract

The wake of a flexible foil undergoing pitching oscillations in a low-speed hydrodynamic tunnel is used to examine the effect of chord-wise foil flexibility in the dynamical features of flapping-based propulsion. We compare the regime transitions in the wake with respect to the case of a rigid foil and show that foil flexibility inhibits the symmetry breaking of the reverse Bénard-von Kármán wake reported in the literature. A momentum balance calculation shows the average thrust to be up to three times greater for the flexible foil than for the rigid foil. We explain both of these observations by analyzing the vortex dynamics in the very near wake.

arXiv comment10 pages

References in corpus (5)

• Transitions in the wake of a flapping foil
• Rather than resonance, flapping wing flyers may play on aerodynamics to improve performance
• Resonance and propulsion performance of a heaving flexible wing
• A model for the symmetry breaking of the reverse Benard-von Karman vortex street produced by a flapping foil
• How wing compliance drives the efficiency of self-propelled flapping flyers

Cited by in corpus (8)

• Unsteady Propulsion by an Intermittent Swimming Gait
• Deflected Wake Interaction of Tandem Flapping Foils
• Classification of vortex patterns of oscillating foils in side-by-side configurations
• A high-fidelity numerical study on the propulsive performance of pitching flexible plates
• Intermittent Unsteady Propulsion with a Combined Heaving and Pitching Foil
• How shape and flapping rate affect the distribution of fluid forces on flexible hydrofoils
• Wake and aeroelasticity of a flexible pitching foil
• Vortex transition and thermal mixing by pitching a perforated flexible panel