1. Introduction 2. Fixed, rigid wing aerodynamics 3. Flexible wing aerodynamics 4. Flapping wing aerodynamics.

/pdf/aerodynamics-of-low-reynolds-number-flyers-4v0j5o71pp.pdf

Aerodynamics of Low Reynolds Number Flyers

Aerodynamic modelling of insect-like flapping flight for micro air vehicles

Aerohydrodynamics of flapping-wing propulsors

This is an ideal book for graduate students and researchers interested in the aerodynamics, structural dynamics and flight dynamics of small birds, bats and insects, as well as of micro air vehicles (MAVs), which present some of the richest problems intersecting science and engineering. The agility and spectacular flight performance of natural flyers, thanks to their flexible, deformable wing structures, as well as to outstanding wing, tail and body coordination, is particularly significant. To design and build MAVs with performance comparable to natural flyers, it is essential that natural flyers' combined flexible structural dynamics and aerodynamics are adequately understood. The primary focus of this book is to address the recent developments in flapping wing aerodynamics. This book extends the work presented in Aerodynamics of Low Reynolds Number Flyers (Shyy et al. 2008).

/pdf/an-introduction-to-flapping-wing-aerodynamics-j5o8vy2ryx.pdf

An Introduction to Flapping Wing Aerodynamics

An analytical treatment to quantify the losses captured in the induced power factor, k, is provided for flapping wings in normal hover, including the effects of non-uniform downwash, tip losses and finite flapping amplitude. The method is based on a novel combination of actuator disc and lifting line blade theories that also takes into account the effect of advance ratio. The model has been evaluated against experimental results from the literature and qualitative agreement obtained for the effect of advance ratio on the lift coefficient of revolving wings. Comparison with quantitative experimental data for the circulation as a function of span for a fruitfly wing shows that the model is able to correctly predict the circulation shape of variation, including both the magnitude of the peak circulation and the rate of decay in circulation towards zero. An evaluation of the contributions to induced power factor in normal hover for eight insects is provided. It is also shown how Reynolds number can be accounted for in the induced power factor, and good agreement is obtained between predicted span efficiency as a function of Reynolds number and numerical results from the literature. Lastly, it is shown that for a flapping wing in hover k owing to the non-uniform downwash effect can be reduced to 1.02 using an arcsech chord distribution. For morphologically realistic wing shapes based on beta distributions, it is shown that a value of 1.07 can be achieved for a radius of first moment of wing area at 40% of wing length.

https://royalsocietypublishing.org/doi/pdf/10.1098/rsif.2013.1196

On the Quasi-Steady Aerodynamics of Normal Hovering Flight Part I: The Induced Power Factor

A method that uses the added mass of vortex sheets was developed to estimate induced power in e apping e ight for birds and insects. This new method has advantages over existing methods. First, it is valid for e ights with any forward velocity. Second, this method can be used to determine the effects of most kinematic parameters of e apping wings on induced power, like the inclination of the stroke plane, amplitude of the e apping angle, and the mean e apping angle. For hovering e ight this method has the same accuracy as methods based on the Rankine ‐ Froude momentum theory or on vortex ring theory. When the forward velocity is large, this method agrees with the momentum theory for a e xed wing.

C. P. Ellington

Papers

Approximate Added-Mass Method for Estimating Induced Power for Flapping Flight