Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 34 for “"High angles of attack"”.
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Cascade performance of double circular arc compressor blades at high angles of attack
The design of a cascade wind tunnel for testing of compressor blades at high angle of attack is described. Methods to insure uniform velocity profiles and control of inlet turbulence are discussed. The problem of maintaining two-dimensional flows at high angle of attack was addressed. A tunnel …
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A numerical method for modelling wings with sharp edges maneuvering at high angles of attack
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1994.
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The efficiency of the vertical tail for different wing-fuselage combinations, particularly at high angles of attack
Thesis: M.S., Massachusetts Institute of Technology, Department of Aeronautical Engineering, 1936
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Space-shuttle windward surface laminar viscous shock-layer flows in equilibrium air at high angles-of-attack
… laminar viscous flows over the windward surface of a shuttle-like vehicle with a perfect gas and an equilibrium air model at high angles-of-attack to simulate reentry conditions. The predictions of wall pressure and heat-transfer data compare well with the limited experimental data available …
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A surface flow visualization study of boundary layer behavior on the blades of a solid-wall compressor cascade at high angles of attack
… circular arc compressor blades in a solid wall, high aspect ratio cascade for the purpose of describing the transition from corner stall to full blade stall, and the blade surface flow under fully stalled conditions. Photos of the visualizations for three stagger angles are presented and …
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Analysis of the dynamic stability derivatives for high angle of attack aircraft
Modern, high performance aircraft are required to be able to fly and be controlled over a wide variety of flight conditions. In order to predict the aircraft behavior and control requirements over the entire flight regime it is necessary to have a proper aerodynamic model. Flight conditions at high …
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Three-dimensional nonequilibrium viscous shock-layer flow over the space shuttle orbiter
… flowfield past the space shuttle orbiter at high angles-of-attack (up to 50-deg). An existing viscous shock-layer method for perfect gas flows has been extended to include finite-rate chemical reactions of multi-component ionizing air. A general nonorthogonal computational grid system was …
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The lateral-directional characteristics of a 74-degree delta wing employing gothic planform vortex flaps
… low-speed lateral-directional characteristics of a generic 74-degree delta wing-body configuration employing the latest generation, gothic planform vortex flaps has been conducted. In addition, the theoretical estimates from VORSTAB were compared against experimental data to aid in documenting …
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Computational Prediction of Stall Aerodynamics and Evaluation of Ground Effect for a Generic Transport Aircraft
Flight safety of modern transport aviation depends to a large extent on the skills of the pilot in dealing with manual aircraft control in critical Flight situations.According to Boeing's document " Statistical Summary of Commercial Jet Air-plane Accidents, Worldwide Operations (1959-2016)" about …
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Steady and unsteady cascade measurements
… were made in a linear stationary cascade of compressor blades under high angles of attack. Laser-doppler velocimetry and flow visualization were used. A method was developed for inducing propagating stall and some triggered ensemble averaged velocity records were obtained. An inviscid …
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Evaluation of the Aerodynamic and Acoustic Performance of a Novel Passive Bat Deterrent for Wind Energy Applications
The growth of wind energy installations and the continued increase in turbine size over recent decades have contributed to a concerning rise in bat fatalities. Current mitigation strategies suffer from limitations, with curtailment decreasing energy production and active acoustic bat deterrents …
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A novel optimised design using slots for flow control and high-lift performance of UCAVs
… has a moderate leading and trailing edges sweep of Λ = 40°, while the other configuration is highly swept with a leading-edge sweep of Λ = 60° and trailing edges sweep of Λ = 40°. The objectives of the present study on UCAV configurations are two-fold: first to predict aerodynamic performance …
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Numerical simulations of subsonic aeroelastic behavior and flutter suppression by active control
… unsteady, subsonic, aeroservoelastic response of a wing has been developed. The air, wing, and control surface are considered to be a single dynamical system. All equations are solved simultaneously in the time domain by a predictor-corrector method. The scheme allows nonlinear aerodynamic and …
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Response surface approximations for pitching moment including pitch-up in the multidisciplinary design optimization of a high-speed civil transport
… characteristic into the design optimization of a high-speed civil transport has been developed. Previously, the tendency of a high-speed aircraft to become uncontrollable (pitch-up) at high angles-of-attack during landing or takeoff for some wing shapes could not be included directly in the …
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The effects of forebody strakes on asymmetric vortices on a vertically launched missile
… air missile model to investigate the effects of forebody stakes on the side forces and yawing moments induced by nose-generated asymmetric vortices at high angles of attack. The effects of body configuration and a turbulent flowfield on the induced side forces and yawing moments were also …
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Active Control of Separated Flow over a Circular-Arc Airfoil
An experimental study of active control of fully separated flow over a symmetrical circular-arc airfoil at high angles of attack was performed. The experiments were carried out in a low-speed, open circuit wind tunnel. Angles of attack from 10 to 40 degrees were tested. Low-power input, unsteady …
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Analysis of the flow structure and reattachment over accelerating non-slender delta-wing planforms
… aircraft and supersonic aircraft. Slender, or high swept, delta wings have been widely studied in early investigations since they suffer less wave drag in supersonic environments. Recently, however, with more and more low-aspect ratio wing applications on UCAVs (Unmanned Combat Aerial Vehicles) …
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The analysis and control of nonlinear systems using Lyapunov stability theory
… theory for the stability analysis and control of nonlinear systems are developed. In the first part of this work, procedures for determining conditions of guaranteed asymptotic stability are developed for nonlinear, uncontrolled systems. A second order model of an aircraft which is potentially …
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Characterization of inclined oscillating jets and crossflow interaction for use in active flow control
… were conducted to understand the interaction of inclined fluidic oscillator jets with a crossflow across a range of different blowing ratios. The fluidic oscillators used in the current study featured rounded internal feedback channels and produced spatially oscillating jets at predictable …
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Development of Methods for Improved Data Integrity and Efficient Testing of Wind Tunnel Models for Dynamic Test Conditions in Unsteady and Nonlinear Flight Regimes
Today's high performance aircraft are operating in expanded flight envelopes, often maneuvering at high angular rates at high angles-of-attack, even above maximum lift. Current aerodynamic models are inadequate in predicting flight characteristics in the expanded envelope, such as rapid aircraft …
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