Труды сотрудников ИЛ им. В.Н. Сукачева СО РАН

[Text] / D. L. GRODNITSKY, P. P. MOROZOV // J. Exp. Biol. - 1993. - Vol. 182. - P11-40. - Cited References: 59 . - 30. - ISSN 0022-0949РУБ Biology

Аннотация: Tethered flight of six insect species (two pentatomid bugs, a moth, a butterfly, a muscid fly and a crane fly) was studied using several modifications of a dust flow visualization procedure. The spatial structure of the near vortex wake of flying specimens was reconstructed on the basis of two-dimensional flow pictures. The dynamics of the wake was followed during a stroke cycle, revealing interspecific differences in vortex formation. It is suggested that insects create a single vortex ring during each stroke. Therefore, the hypothesis of double vortex chains advanced by Brodsky is not verified. The same is true of the jet hypothesis of Bocharova-Messner. While pronating at the top of their trajectory, the flapping wings throw air masses off their lower surfaces, but there is not a jet from between their upper sides. Flow separation from leading edges was found to be a rare phenomenon, taking place irregularly during the stroke cycle. That is why, contrary to widespread theoretical expectations, the Weis-Foch fling mechanism is not likely to contain a leading edge separation bubble, which must follow stalling at the front part of the wings. It is suggested that flying animals possess special mechanisms for extracting energy back from the near vortex wake. Some hypothetical adaptations for such an extraction in insects are put forward. Possible pathways for the evolution of insect flight are described.


Доп.точки доступа:
GRODNITSKY, D.L.; MOROZOV, P.P.

[Текст] / D. L. GRODNITSKY // Zool. Zhurnal. - 1992. - Vol. 71, Is. 4. - С. 21-28. - Cited References: 27 . - 8. - ISSN 0044-5134РУБ Zoology

Аннотация: Several kinematic parameters of wings and linked with them vertical oscillations of the body were studied analyzing cinema films of 3 butterfly species flying free and being tethered. Tethered insects demonstrated prolonged near harmonic strokes. Contrary to that in free flight downstroke lasts more than the upstroke. Butterflies change relationship between lift and thrust changing the angle between longitudinal body axis and the horizon. Absolute value of aerodynamic force is regulated with stroke amplitude. Lift may be enhanced by increasing relative duration of downstroke. interrelationship between wing kinematics and periodical vertical body movements shows that almost no sustaining force is generated during Weis-Fogh's clap-and-fling. Maximal lift values have place in the lower part of downstroke. New data do not support the hypothesis on the role of reactive force in insect flight.


Доп.точки доступа:
GRODNITSKY, D.L.