Results 251 to 260 of about 587,209 (299)

Dynamic flight stability of a bumblebee in forward flight

Acta Mechanica Sinica, 2007
The longitudinal dynamic flight stability of a bumblebee in forward flight is studied. The method of computational fluid dynamics is used to compute the aerodynamic derivatives and the techniques of eigenvalue and eigenvector analysis are employed for solving the equations of motion. The primary findings are as the following.
Yan Xiong, Mao Sun
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Oxygen consumption of bumblebees in forward flight

Nature, 1990
AERODYNAMIC theories predict that the mechanical power required for flapping animal flight varies with flight speed according to a 'U-shaped' curve1–6. At some intermediate speed there is a pronounced power minimum, typically half the power required for hovering flight. These theories are widely used for birds and bats, but the predictions are not well
C. P. Ellington, K. E. Machin, Timothy M. Casey   +2 more
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Propeller Ground Effect in Forward Flight

AIAA Journal, 2023
The study of the fixed-pitch small-scale propeller in-ground effect is extended to forward flight conditions at different incidence angles of the propeller. Force-based experiments, smoke flow visualization, surface flow visualization, and phase-locked particle image velocimetry (PIV) indicate the presence of three distinct performance zones as a ...
Jielong Cai, Sidaard Gunasekaran
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Jet noise source modification due to forward flight

15th Aerospace Sciences Meeting, 1977
The effects of forward flight on the turbulence characteristics of a jet in a co-flowing stream have been determined for a 2.22 inch circular jet in a 36 inch free jet wind tunnel. The nozzle exit velocity was 400 ft/sec, and the tunnel velocity was set at 0, 40, 120 and 200 ft/sec.
R. S. Larson, C. J. McColgan, A. B. Packman   +2 more
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Lateral dynamic flight stability of a model bumblebee in hovering and forward flight

Journal of Theoretical Biology, 2013
The lateral dynamic flight stability of a model bumblebee in hovering and forward flight is studied, using the method of computational fluid dynamics to compute the stability derivatives and the techniques of eigenvalue and eigenvector analysis for solving the equations of motion.
Xu, Na, Sun, Mao
openaire   +3 more sources

Forward Flight Effects on Chevron Noise Reduction

14th AIAA/CEAS Aeroacoustics Conference (29th AIAA Aeroacoustics Conference), 2008
Jet engine exhaust nozzle chevron designs are used for reducing low frequency jet noise by enhancing the jet mixing process. The development of an empirical method to predict the effect of chevrons, based on a static engine test, can eliminate the need to flight test every engine/airplane combination and therefore would be of important practical value ...
Eric Nesbitt, Russell Young
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Propeller thrust and drag in forward flight

2017 IEEE Conference on Control Technology and Applications (CCTA), 2017
This paper presents a methodology for modelling the thrust, drag, and torque of propellers used in unmanned-aerial-vehicle (UAV) applications. The model can be used in wide flight regimes from hover to high speed forward flight and is derived from first-principles using Blade Element Theory (BET), Blade Element Momentum Theory (BEMT), and a parameter ...
Rajan Gill, Raffaello D'Andrea
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Forward flight effects on EBF noise

4th Aeroacoustics Conference, 1977
Forward flight effects on local mean velocity and turbulence velocity profiles, surface pressure spectra, and far field acoustic pressure spectra were measured for a simple externally blown flap (EBF). Both upper-surface-blowing and under-the-wing configurations were tested.
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Forward flapping flight from flexible fins

Canadian Journal of Zoology, 1988
The mechanics and energetics of aquatic flight by the clearnose skate (Raja eglanteria) are examined with cinefilm and a new theoretical approach toward flight mechanics. Film analyses show that these animals move with a flapping, flexing wing that has a propulsive wave travelling rearward at twice the forward speed of the animal.
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Numerical Simulation of Autorotation in Forward Flight

Journal of Aircraft, 2009
Autorotation in forward flight is an important subject for gyroplanes or compound helicopters. By integrating the flapping and rotational equations of motion, we investigate in this work the steady-state autorotation of a three-bladed rotor for a given set of three independent variables: forward velocity, collective pitch angle, and shaft angle.
Kim, HY Kim, Hak Yoon, Sheen, DJ Sheen, Dong Jin, Park, SO Park, Seung O   +2 more
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