In many aerospace engineering design problems, objective function evaluations can be extremely computationally expensive, such as the optimal design of the aerodynamic shape of an airfoil using high-fidelity computational fluid dynamics (CFD) simulation. A widely used approach for dealing with expensive optimization is to use cheap global surrogate (approximation) models to substitute expensive...

The aerodynamic roughness is one of the major parameters in describing the turbulent exchange process between terrestrial and atmosphere. Remote Sensing is recognized as an effective way to inverse this parameter at the regional scale. However, in the long time the inversion method is either dependent on the lookup table for different land covers or the Normalized Difference Vegetation Index (N...

Aerodynamic theory has long been used to predict the power required for animal flight, but widely used models contain many simplifications. It has been difficult to ascertain how closely biological reality matches model predictions, largely because of the technical challenges of accurately measuring the power expended when an animal flies. We designed a study to measure flight speed-dependent a...

Aerodynamic contrails form when air flows across the wings of subsonic aircraft in cruise. During a short adiabatic expansion phase, high supersaturations trigger burst-like homogeneous ice formation on ambient liquid aerosol particles within a wing depth. Small particles freeze first, because they equilibrate most rapidly. Ambient temperature is the key determinant of nascent aerodynamic contr...

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...

this paper presented methods to determine the aerodynamic forces that acton an aircraft wing during flight. these methods are initially proposed for asimplified two degree-of-freedoms airfoil model and then are extensivelyapplied for a multi-degree-of-freedom airfoil system. different airspeedconditions are considered in establishing such methods. the accuracy of thepresented methods is verifie...

Aerodynamic design algorithms require an optimization strategy to search for the best design. The object of this paper is to compare the performance of some different strategies when used by an aerodynamic shape optimization routine which designs fan blade shapes. A recently developed genetic algorithm, Differential Evolution [1,2], outperforms more traditional techniques.

Recent work on a novel approach to the control of the aerodynamic performance of lifting surfaces by fluidic modification of their apparent aerodynamic shape, or virtual aerosurface shaping is reviewed. This flow control approach emphasizes fluidic modification of the “apparent” aerodynamic shape of the surface with the objective of altering or prescribing the streamwise pressure gradient. Cont...

Reynolds number and thus body size may potentially limit aerodynamic force production in flying insects due to relative changes of viscous forces on the beating wings. By comparing four different species of fruit flies similar in shape but with different body mass, we have investigated how small insects cope with changes in fluid mechanical constraints on power requirements for flight and the e...