Three-dimensional effects on the aerodynamic performance of flapping wings in tandem configuration Articles uri icon

publication date

  • April 2020

start page

  • 1

end page

  • 16


  • 102893


  • 94

International Standard Serial Number (ISSN)

  • 0889-9746

Electronic International Standard Serial Number (EISSN)

  • 1095-8622


  • Direct numerical simulations have been performed to analyze how three-dimensional
    effects influence the performance of wings in tandem configuration undergoing a two-
    dimensional optimal kinematics. This optimal motion is a combination of heaving and
    pitching of the airfoils in a uniform free-stream at a Reynolds number Re = 1000
    and Strouhal number Stc = 0.7. Wings of two different aspect ratios, AR = 2 and 4,
    undergoing the 2D motion have been considered. It has been found that the interactions
    between the vortical structures of the fore- and the hind-wings are qualitatively similar
    to the two-dimensional case for both AR. However, the ratio between the mean thrust
    of the hind-wing and the fore-wing decreases from 80% in 2D to 70% in 3D, implying
    that the 3D effects are detrimental for the vortical interactions between the wings in
    terms of thrust production. Nonetheless, the propulsive efficiency remains constant both
    in 2D and 3D, for both AR. A more realistic flapping motion has also been analyzed and
    compared to the heaving motion. It has been found that the aerodynamic forces decrease
    when the wings are in flapping motion. This detrimental behavior has been linked to a
    sub-optimal motion of the inboard region of the wings. This sub-optimal region of the
    wings entails a decrease of the mean thrust and of the propulsive efficiency


  • Aeronautics


  • wings; aerodynamic forces; reynolds number; strouhal number; direct numerical simulation