Analysis of the aerodynamic forces acting on baseball pitches from major league games reveals a large variance in the measured coefficients of lift and drag. We have examined possible explanations for this effect and found that, while uncertainties introduced by measurement error and the method of reporting major league pitch trajectories do explain some of the spread, the reasons for the large...

Soaring raptors can fly at high altitudes of up to 9000 m. The behavioural adjustments to high-altitude flights are largely unknown. We studied thermalling flights of Himalayan vultures (Gyps himalayensis) from 50 to 6500 m above sea level, a twofold range of air densities. To create the necessary lift to support the same weight and maintain soaring flight in thin air birds might modify lift co...

In recent years the demand for Unmanned Aerial Vehicles (UAV's) has increased rapidly across many different industries and they are used for various applications. Such systems have the ability to enter dangerous or inaccessible environments and allow vital information to be collected without human risk. In order to carry out a task, a UAV has to face many different challenges. This has led to t...

The higher pollutant level in non premixed combustion and safety issues pertaining to can be counteracted by partially-premixed mode of combustion. partially flames (PPF) exhibit the benefits both flames. PPF enhances complete leading reduced soot formation hence lower emission. However, equivalence ratio plays an important role stability such This paper reports experimental investigation on fl...

A finite element flow solver based on unstructured grids is employed for studying the aerodynamic characteristics of Micro Air Vehicles. Inviscid and viscous flow simulations were performed for two different Micro Air Vehicles developed at NRL. Lift and drag force variations were computed for a range of flow angles and control surface angles. The Baldwin-Lomax turbulence model was employed for ...

For centuries, mankind has been fascinated by V-formation flight in birds. Back in AD 79, Pliny the Elder noted that flocks of geese flew ‘like fast galleys, cleaving the air more easily than if they drove at it with a straight front’, and since then, numerous ideas have been proposed to explain the function of the V-shaped flocks that are a such a familiar sight. Many of these explanations oft...

Citric acid production is generally carried out in an aqueous medium stirred tank reactors (STR), where the solubility of oxygen low and demand microbial cultures high. Thus, for this bioprocess, providing adequate mass transfer rate (OTR) from gas phase into culture main challenge bioreactor selection operation. In study, citric by Yarrowia lipolytica W29 crude glycerol, batch cultures, was pe...

A flight-dynamics oriented simulation model of a flapping-wing Micro Air Vehicle (MAV) has been developed. This concept is based on flapping flight performed in nature by insects or hummingbirds. An optimization of the flapping kinematics of the wing has been led, in order to maximize the mean lift and thus the payload. A neural network has been designed to reproduce the function shape of the w...

Cl = section lift coefficient c = local chord length D = fading-memory constant G = nondimensional circulation l = section lift force/length m = number of points used in sine series expansion of circulation function N = consecutive iterations convergence parameter r = perpendicular distance from vortex tol = iteration relative tolerance of conversion U1 = freestream velocity magnitude w = downw...