Flapping Wing Flight in Turbulence

Bixing Yan, Purdue University

Abstract

Flapping wing flight always interests people, scientists have devoted years trying to figure out the principle of flapping wing flight as well as inventing flapping wing applications. Recently, the flapping wing flight in turbulence has drawn more attention. Some biologists found that the turbulence does have an instability effect on the body posture and flight performance of insects [5], but they can still have a relatively stable and robust flying routes, especially during the migration [29]. How could they fly in the heavy turbulence? Do they have an internal turbulence decoupling mechanism? With the interests to flapping wing flight and hoping to find out how turbulence will affect the flight performance of flapping wing insects, this thesis research was designed and performed. A homogeneous and isotropic turbulence (HIT) was created in the laboratory environment and a mechanical flapper was designed to mimic the flapping motion of insects. The lift and drag coefficients were measured in both steady flow and HIT. Then the flapping experiment with different flapping frequency was also conducted to investigate whether the flapping frequency is related to the potential turbulence decoupling mechanism. There is no significant change in cycle-averaged aerodynamic forces for both steady flow and HIT after carefully reviewing and analyzing the experimental data, Also, both single and dual wing generate the same magnitude of aerodynamic forces either in turbulence or HIT case, in other words, the wing-wing interaction is not obvious. Last, there is no clear changing on the aerodynamic forces when varying the flapping frequency and the potential turbulence decoupling mechanism may not be frequency related. However, the potential turbulence decoupling mechanism still remains unclear and further study is needed.

Degree

M.S.M.E.

Advisors

Deng, Purdue University.

Subject Area

Mechanical engineering

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