The efficient direct optimization method is developed for aerodynamic shapes design at subsonic and supersonic flow regimes. The method combines Newton based algorithm with CFD modeling and is capable of handling large number of design variables. Aerodynamic drag is considered as the objective function minimized under volume and overall dimensions constraints. The efficiency of the method is de...

A numerical procedure is described in which the aerodynamic drag and torque in low Earth orbit are calculated for a prototype Space Shuttle external tank and its components, the "LO2" and "LH2" tanks, carrying liquid oxygen and hydrogen, respectively, for any given angle of attack. Calculations assume the hypersonic limit of free molecular flow theory. Each shell of revolution is assumed to be ...

Wilson's storm petrel (Oceanites oceanicus) characteristically feeds by ' hovering' over the water surface, but its technique for this is unlike that of other flying vertebrates. The kinematics and aerodynamics of this ' hovering' flight were investigated to determine the possible sources of lift; various nonaerodynamic sources of lift were discounted. It is suggested that the storm petrel soar...

During slow flight, bird species vary in their upstroke kinematics using either a 'flexed wing' or a distally supinated 'tip-reversal' upstroke. Two hypotheses have been presented concerning the function of the tip-reversal upstroke. The first is that this behavior is aerodynamically inactive and serves to minimize drag. The second is that the tip-reversal upstroke is capable of producing signi...

When cycling on level ground at a speed greater than 14 m/s, aerodynamic drag is the most important resistive force. About 90% of the total mechanical power output is necessary to overcome it. Aerodynamic drag is mainly affected by the effective frontal area which is the product of the projected frontal area and the coefficient of drag. The effective frontal area represents the position of the ...

Aerodynamic drag is the cause for more than two-thirds of the fuel consumption of large trucks at highway speeds. Due to functionality considerations, the aerodynamic efficiency of the aft regions of large trucks was traditionally sacrificed. This leads to massively separated flow at the lee side of truck trailers, with an associated drag penalty: roughly a third of the total aerodynamic drag. ...

A reliable and fast method of predicting complex aerodynamic coefficients for flight simulation is presented using neural networks. The training data for the neural network is derived from numerical simulations and wind-tunnel experiments. The aerodynamic coefficients are modeled as functions of the flow characteristics and the control surfaces of the vehicle. The basic coefficients of lift, dr...

Soccer balls such as the Adidas Roteiro that have been used in soccer tournaments thus far had 32 pentagonal and hexagonal panels. Recently, the Adidas Teamgeist II and Adidas Jabulani, respectively having 14 and 8 panels, have been used at tournaments; the aerodynamic characteristics of these balls have not yet been verified. Now, the Adidas Tango 12, having 32 panels, has been developed for u...

Using 3D infrared high-speed video, we captured the continuous wing and body kinematics of free-flying fruit flies, Drosophila melanogaster, during hovering and slow forward flight. We then 'replayed' the wing kinematics on a dynamically scaled robotic model to measure the aerodynamic forces produced by the wings. Hovering animals generate a U-shaped wing trajectory, in which large drag forces ...

SUMMARY There is a need for a wave drag method that combines the speed of handbook methods with the accuracy of computational methods. Especially determining the onset of wave drag as well as the initial drag rise is important in initial design stages. Meta-models allow this by capturing the trends present in previously computed data, providing an accurate and fast representation. In this repor...