Concise Perspective and Previous Surveys W HEN reviewing research in rotary-wing aeroelasticity (RWA), it is important to mention a few historical facts. The Wright brothers flew in 1903, and Sikorsky built and started flying the first operational helicopter, the R-4 or (VS-316), in 1942. The R-4 was a three-bladed helicopter with a rotor diameter of 11.6 m and was powered by a 185-hp engine. T...

The aerodynamics of high-speed vehicles in evacuated tunnels is studied with particular reference to the consequences choked flow conditions at tails vehicles. It shown that this has a dominant influence on overall (pressure, temperature, velocity). Together need for tunnel system be closed, high speeds cause aerodynamic behaviour differ greatly from conventional railway tunnels. A key purpose ...

The objective of this study is to minimize the drag coefficient of aerodynamics bodies for a specified design Reynolds number regime. With the aerodynamics model the gradient of the objective function (drag coefficient) cannot be determined analytically. Furthermore, it is expected that the objective function is multi-modal, i.e. it shows more than one minimum. Therefore, the optimization algor...

Aerodynamic forces on bridges are commonly separated into static, self-excited, and buffeting force components. By delving into the relationships among force descriptors for static, self-excited, and buffeting components, novel perspectives are developed to unveil the subtle underlying complexities in modeling aerodynamic forces. Formulations for airfoil sections and those based on quasisteady ...

The creation of an integrated rotorcraft conceptual and preliminary design framework at DLR involved the development of geometry and fuselage aerodynamics modules at the Institute of Aerodynamics and Flow Technology. After a short revision of the RIDE rotorcraft design environment architecture this paper focuses on the implementation of these disciplinary modules. The aim of the geometry module...

The present research investigates the torsional aeroelasticity of the blade of an H-type vertical axis wind turbine subject to stall and post-stall conditions in various Reynolds regimes, which is experienced by the blade in a full revolution. In order to simulate the aerodynamics, a new model based on a combination of the Double Multi Streamtubes (DMST) model and the nonlinear multi-criteria C...

The aerodynamics of micro air vehicles (operating at the chord Reynolds number of 10 5 or below) is substantially influenced by the unsteadiness of the wind gust and the aircraft’s light weight. In this effort, we investigate the active flow control of the dielectric barrier discharge actuator for flows around the SD7003 airfoil, with the chord Reynolds number of 6×10 4 , to enhance our underst...

The basis of this work was to understand the generation of lift and thrust of a flapping biwing ornithopter, which is influenced by its geometrical, dynamic, kinematic and aerodynamic features by following a generic approach in order to identify and mimic the mechanisms. As further development of earlier work, three-dimensional rigid thin wing is considered in flapping and pitching motion using...

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...

Lockheed Martin Skunk Works, under a cooperative agreement with NASA, will build and fly the X-33, a half-scale prototype of a rocket-based, single-stage-to-orbit (S S T O) , reusable launch vehicle (RLV). A 0.007-scale model of the X-33 604B0002G configuration was tested in four hypersonic facilities at the NASA Langley Research Center to examine vehicle stability and control characteristics a...