The aerodynamic characteristics of the wings and body of a dragonfly and of artificial wing models were studied by conducting two types of wind-tunnel tests and a number of free-flight tests of gliders made using dragonfly wings. The results were consistent between these different tests. The effects of camber, thickness, sharpness of the leading edge and surface roughness on the aerodynamic cha...

We present the numerical study of the statistical properties of the partially coherent quasi-CW high-Q cavity Raman fiber laser. The statistical properties are different for the radiation generated at one or many cavity passes. It is found that rare extreme events are generated at the far spectral wings of the spectrum. The mechanism of the extreme events generation is a turbulent-like four-wav...

Abstract Frequency-domain unsteady lifting-line theory (ULLT) provides a means by which the aerodynamics of oscillating wings may be studied at low computational cost without neglecting interacting effects aspect ratio and oscillation frequency. Renewed interest in method has drawn attention to several uncertainties however. Firstly, what extent is ULLT practically useful for rectangular wings,...

Magadacerina forcipata, new genus, new species (Trichoptera: Leptoceridae), is described from Madagascar. The monotypic genus is characterised by having the tibial spur formula 2,2,2; wings with sessile bifurcation of M; genitalia with preanal appendages fused with segment IX and greatly produced posterad, and a tergum X with an anteriorly extended ventral base articulating with a sclerotised s...

Adults, particularly males, of a papilionid butterfly, Papilio machaon hippocrates, emit a fairly strong scent perceivable by humans. We have identified a variety of volatile compounds (hydrocarbons, alcohols, aldehydes, ketones, esters, and so on) from the wings and bodies of both sexes of the butterfly. Male wings secreted n-dodecane, linalool and geranylacetone as major components together w...

Human pilots have the extraordinary ability to remotely maneuver small Unmanned Aerial Vehicles (UAVs) far outside the flight envelope of conventional autopilots. Given the tremendous thrustto-weight ratio available on these small machines [1, 2], linear control approaches have recently produced impressive demonstrations that come close to matching this agility for a certain class of aerobatic ...

Recent work on the aerodynamics of flapping flight reveals fundamental differences in the mechanisms of aerodynamic force generation between fixed and flapping wings. When fixed wings translate at high angles of attack, they periodically generate and shed leading and trailing edge vortices as reflected in their fluctuating aerodynamic force traces and associated flow visualization. In contrast,...