Based on the adjoint method, afterbody of a military transport aircraft was optimized and designed to meet engineering constraints under real flight conditions. Guidance for key design parameters is given. The vortex dynamics boundary layer extraction methods were used analyze optimization results aircraft. It found that, upstream shedding point, circumferential accumulation process vorticity w...

Changing aircraft operational procedures is one strategy that can be used to reduce fuel burn and mitigate environmental impacts of aviation in relatively short timeframes with existing aircraft types. This study quantifies the fuel burn and emissions reduction potential of delayed deceleration approaches, where the aircraft is kept fast and in clean aerodynamic configuration for as long as pos...

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...

A new optimization approach for robust design, design for multi-objective six sigma (DFMOSS) has been developed and applied to robust aerodynamic airfoil design for Mars exploratory airplane. The present robust aerodynamic airfoil design optimization using DFMOSS successfully showed the trade-off information between maximization and robustness improvement in aerodynamic performance by a single ...

L OW-REYNOLDS-NUMBER airfoil aerodynamics is important for bothmilitary and civilian applications. The applications include propellers, sailplanes, ultralight man-carrying/man-powered aircraft, high-altitude vehicles, wind turbines, unmanned aerial vehicles (UAVs), and micro air vehicles (MAVs). For the applications just listed, the combination of small length scale and low flight velocities re...

We present the results of an experimental investigation on the wrinkling of positively curved surfaces and explore their use towards drag reduction applications. In our precision model experiments we make use of rapid prototyping techniques to cast samples with custom geometry and material properties out of silicone-based rubbers. Our structures consist of a thin stiff shell that is chemically ...