Stabilizing effect of flexibility in the wake of a flapping foil

flex_vs_rig_jetStabilizing effect of flexibility in the wake of a flapping foil
C. Marais; B Thiria; Wesfreid, J. E. & R. Godoy-Diana.
Journal of Fluid Mechanics, 710 : 659-669 (2012).

Abstract: The wake of a flexible foil undergoing pitching oscillations in a low-speed hydrodynamic tunnel is used to examine the effect of chordwise 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 analysing the vortex dynamics in the very near wake.

BibTeX:

@article{marais2012,
  author = {{M}arais, C. and {T}hiria, {B} and {W}esfreid, {J}. {E}., and {G}odoy-{D}iana, {R}.},
  title = {Stabilizing effect of flexibility in the wake of a flapping foil},
  journal = {Journal of Fluid Mechanics},
  year = {2012},
  volume = {710},
  pages = {659-669}
}

Article in the publisher site: [doi:10.1017/jfm.2012.390]
Article here: [PDF file]

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