airplane in presence of asymmetric left-wing damaged. ‎Variations of the aerodynamic parameters, mass and ‎moments of inertia, and the center of gravity due to ‎damage are all considered in the nonlinear ‎mathematical modeling. The proposed discrete-time ‎nonlinear MRAC algorithm applies the recursive least ‎square (RLS) algorithm as a parameter estimator as ‎well as the error between the real ...

Nomenclature C = chord length, m C T = thrust coefficient f = flapping frequency, Hz h tip = plunge amplitude at the wing tip, m k = ωC∕U ∞ , reduced frequency l span = wingspan, m Re = U ∞ C∕ν, Reynolds number r z = z-directional distance away from the wing tip, m S wing = wing area, m 2 St = fh tip ∕U ∞ , Strouhal number U ∞ = freestream velocity, m∕s ν = kinematic viscosity of fluid, m 2 ∕s ...

Fifty-four skeins of pink-footed geese (Anser brachyrhynchus) were photographed from directly underneath to eliminate the effects of perspective distortion, and the wing-tip spacings (the distance between adjacent birds' wing tips perpendicular to the flight path at maximum wingspan) and depths (the distance between adjacent birds' body centres parallel to the flight path) were measured at the ...

An often overlooked aspect of digit development is the special nature of the terminal phalanx, a specialized structure with characteristics distinct from other phalanges, for example the presence of ectodermal derivatives such as nails and claws. Here, we describe the unique ossification pattern of distal phalanges and characteristic gene expression in the digit tips of chick and duck embryos. ...

Wingtip vortex flow is of great importance because of its effect on practical problems such as landing separation distances for aircraft, blade/vortex interactions on helicopter blades, and propeller cavitations on ships. Extensive investigations have been conducted to improve the understanding of the tip vortex structure and its dissipation or persistence analytically, numerically, and experim...

Experimental measurements and analysis of the flight of bats are presented, including kinematic analysis of high-speed stereo videography of straight and turning flight, and measurements of the wake velocity field behind the bat. The kinematic data reveal that, at relatively slow flight speeds, wing motion is quite complex, including a sharp retraction of the wing during the upstroke and a broa...

The formation of the tip-vortex from a rectangular NACA 2415 wing-tip at a chord Reynolds number of 10000 has been simulated. The simulations employ a parallelized compressible large-eddy simulation (LES) solver that has been developed to simulate wing and rotor tip-flows. The solver employs an immersed-boundary technique in conjunction with a curvilinear structured grid and the dynamic model i...

Rhinolophus euryale and R. mehelyi are morphologically very similar species and their distributions overlap extensively in the Mediterranean basin. We modelled their foraging behaviour using echolocation calls and wing morphology and, assuming niche segregation occurs between the two species, we explored how it is shaped by these factors. Resting frequency of echolocation calls was recorded and...

Let (x, y, z) be a rectangular coordinate system, with +x in the direction of the undisturbed freestream flow velocity, +y normal to the plane of the thin wing, and z in the direction of the " span " of the wing. The wing is located on the y = 0 plane, " centered " at z = 0. We are given a large aspect ratio wing with the following information: Planform of the wing is described by c(z), the cho...