Issue
Europhys. Lett.
Volume 74, Number 1, April 2006
Page(s) 55 - 61
Section Electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics
DOI http://dx.doi.org/10.1209/epl/i2005-10490-6
Published online 17 February 2006
Europhys. Lett., 74 (1), pp. 55-61 (2006)
DOI: 10.1209/epl/i2005-10490-6

A transition from ascending flight to vertical hovering: A study of a symmetric flapping model

M. Iima and T. Yanagita

Research Institute for Electronic Science, Hokkaido University Sapporo, 606-0812, Japan


received 22 November 2005; accepted in final form 31 January 2006
published online 17 February 2006

Abstract
We study the motion of a model equipped with flapping wings under the influence of gravity (external force). This model moves in a two-dimensional fluid according to the hydrodynamic force generated by vortices separated from its wings. As a result of the interaction between the vortices and the wings, the model moves steadily in a direction against the gravity. Moreover, hovering, i.e., a steady flight staying in a particular position, can be achieved here by the effective use of vortex structures enhancing the hydrodynamic force that supports the model against gravity. The system exhibits a transition from the state with hovering to a state where hovering is impossible, as the model parameters are changed.

PACS
47.20.Ky - Nonlinearity, bifurcation, and symmetry breaking.
47.32.cb - Vortex interactions.
47.63.-b - Biological fluid dynamics.

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