Kinematics and inertial effects in locust flapping wings

Sergey V Shkarayev, Rajeev Kumar

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations

Abstract

Instantaneous aerodynamic forces on flapping wings are influenced by inertia of the moving masses of the wings. In the present study, the inertial forces and kinematics of wings of the locust Schistocerca americana were investigated experimentally. The developed experimental setup includes freshly extracted hindwings and forewings, mechanical transmission producing active pitching and flapping, a vacuum chamber, and a high-speed video system. Masses and locations of mass centers were measured and averaged based on data collected for four locusts. Videos were taken and time-resolved displacements of a set of point markers on the surface of flapping-pitching wings were obtained. Flapping angle amplitudes, determined at the middle section, are practically the same in air and in vacuum in both forewings and hindwings. Pitching amplitudes at the root and midsection of hindwing differ by up to 50% due to torsional deformation or twist. In the air, the average twist angles are 3 degrees and 18 degrees in forewings and hindwings, respectively. This is due to higher torsional stiffness of the forewings as compared to hindwings. Substantial increase of the twist deformations of the forewings in vacuum was observed and attributed to the removal of aerodynamic damping. Also, in air, the high frequency components are damped out, indicating increased aerodynamic damping at higher flow accelerations. Inertial forces are calculated based on a rigid-body model of a wing with prescribed displacements. The segmentation of a wing into meshes of different topology affects the results of calculations influenced by wing's flexibility. For the same forewing and hindwing tested in air and in vacuum, amplitudes of inertial forces in the air are substantially lower due to the air damping effects reducing wing oscillations.

Original languageEnglish (US)
Title of host publication32nd AIAA Applied Aerodynamics Conference
PublisherAmerican Institute of Aeronautics and Astronautics Inc.
ISBN (Print)9781624102882
DOIs
StatePublished - Jan 1 2014
Event32nd AIAA Applied Aerodynamics Conference 2014 - Atlanta, GA, United States
Duration: Jun 16 2014Jun 20 2014

Publication series

Name32nd AIAA Applied Aerodynamics Conference

Other

Other32nd AIAA Applied Aerodynamics Conference 2014
CountryUnited States
CityAtlanta, GA
Period6/16/146/20/14

ASJC Scopus subject areas

  • Aerospace Engineering
  • Mechanical Engineering

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  • Cite this

    Shkarayev, S. V., & Kumar, R. (2014). Kinematics and inertial effects in locust flapping wings. In 32nd AIAA Applied Aerodynamics Conference (32nd AIAA Applied Aerodynamics Conference). American Institute of Aeronautics and Astronautics Inc.. https://doi.org/10.2514/6.2014-2833