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 89 for “"aerodynamic forces"”.
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Inferential measurement of aerodynamic forces for use in wing divergence analysis
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1959.
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Time domain modeling of unsteady aerodynamic forces on a flapping airfoil
… code to compute the unsteady lift and thrust forces generated by a flapping airfoil and apply it to engineering problems. We consider both plunging and pitching types of motion and develop a time marching simulation based on early work in unsteady aerodynamics. The ability of the code to …
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Dynamic control of aerodynamic forces on a moving platform using active flow control
The unsteady interaction between trailing edge aerodynamic flow control and airfoil motion in pitch and plunge is investigated in wind tunnel experiments using a two degree-of-freedom traverse which enables application of time-dependent external torque and forces by servo motors. The global …
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Development of a Methodology to Measure Aerodynamic Forces on Pin Fins in Channel Flow
… strain gauges to simultaneously measure aerodynamic lift and drag forces on a pin fin. After eliminating the detrimental environmental influences, forces as small as one-tenth the weight of a paper clip are successfully measured. Although the drag of an infinitely long cylinder in uniform …
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Time-Domain Simulations of Aerodynamic Forces on Three-Dimensional Configurations, Unstable Aeroelastic Responses, and Control by Neural Network Systems
The nonlinear interactions between aerodynamic forces and wing structures are numerically investigated as integrated dynamic systems, including structural models, aerodynamics, and control systems, in the time domain. An elastic beam model coupled with rigid-body rotation is developed for the wing …
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Aerodynamic Modeling Using Computational Fluid Dynamics and Sensitivity Equations
A mathematical model for the determination of the aerodynamic forces acting on an aircraft is presented. The mathematical model is based on the generalization of the idea of aerodynamically steady motions. One important use of these results is the determination of steady (time-invariant) …
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The aerodynamic and structural study of flapping wing vehicles
This thesis reports on the aerodynamic and structural study carried out on flapping wings and flapping vehicles. Theoretical and experimental investigation of aerodynamic forces acting on flapping wings in simple harmonic oscillations is undertaken in order to help conduct and optimize the …
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Aerodynamic stability analysis of a CubeSat in high-speed rarefied flow
… Orbit, particularly at altitudes with measurable aerodynamic effects. It is important to design these spacecraft, which often have modest control authority, such that the resultant aerodynamic forces and moments do not cause unstable motion, which may lead to premature loss of mission. Building …
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An experimental investigation of full-scale sail aerodynamics using pressures, shapes and forces
Sail aerodynamics is an active field of study in the research community. The basic behaviour of sails in steady conditions is well known due to numerical computations and wind tunnel testing, but there are several unanswered questions about the sail aerodynamics in actual, dynamic, sailing …
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Reduction of Helmet Buffeting in Open Cockpit, Single Seat Race Cars
… cockpit race cars frequently experience large aerodynamic forces which act on the helmet. These forces, specifically the aerodynamic buffeting of the helmet, reach levels which are very fatiguing and distracting to the driver, and are therefore unacceptable. Little investigation has been done …
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The control of turbulent flows around bluff bodies by means of spanwise sinusoidal profiles
… subsequent shedding of vortices gives rise to aerodynamic forces with large fluctuating components. As a result, significant oscillations are induced, which can lead to resonances and structural fatigue. To obviate these deleterious effects passive flow control mechanisms can be incorporated …
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Flapping-Torsional Response of Helicopter Rotor Blades to Turbulence Excitation
… Classical steady theory is used to formulate the aerodynamic forces due to blade flapping. For those due to blade pitching, a quasi-steady theory is used. The governing equations so obtained contain random turbulence terms in the coefficients and the inhomogeneous parts.
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A study of supersonic flow past vibrating shells and cascades
… methods. Pressure distributions and generalized aerodynamic forces are computed for arbitrary radius to length ratios, axial and circumferential wave numbers, Mach numbers, and reduced frequencies. Excellent agreement is obtained with a previous solution of the complete unsteady linearized …
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Model to Evaluate the Aerodynamic Energy Requirements of Active Materials in Morphing Wings
… the force, stroke, and energy needed to overcome aerodynamic loads encountered by morphing wings during aircraft maneuvers. This low-cost model generates wing section shapes needed to follow a desired flight path, computes the resulting aerodynamic forces using a unique combination of conformal …
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An experimental investigation into the most prominent sources of uncertainty in wave tank testing of floating offshore wind turbines
… errors due to incorrect replication of mooring forces and aerodynamic forces from the turbine. Scaling wind turbine blade properties can be challenging; this is because aerodynamic forces are scaled using Reynolds scaling, but all hydrodynamic forces are scaled using Froude scaling. For this …
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Optimization of surface dielectric barrier discharge ion sources for electroaerodynamic propulsion
… that can be used to generate ions and produce aerodynamic forces in air. They have been studied for aerodynamic flow control and proposed for small aircraft propulsion as both direct sources of thrust and as ion sources for "decoupled" electroaerodynamic (EAD) propulsion, in which decoupling …
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An experimental study of the relationship between forces and moments and vortex breakdown on a pitching delta wing
… sinusoidal increase in angle of attack and hold. Aerodynamic forces and moments were obtained from a six-component internal strain-gauge balance. In addition, smoke flow visualization was conducted to study the development, and breakdown of the leading-edge vortices under static, dynamic, and ramp …
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A model of quadrotor UAV power consumption and its performance across a range of flight conditions
… climb power---that depend on estimates of the aerodynamic forces and moments acting on the quadrotor. The model's accuracy was measured across a wide range of flight conditions. The results of an ablation study to show the relative contribution of each term are presented, concluding that the …
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Research on the Unmanned Aerial Vehicle Design
… results and experimental measurements of the aerodynamic forces show that the axis symmetric craft has asymmetric aerodynamic properties caused by propeller slipstream. The non-intuitive aerodynamics requires a careful selection of the position of the centre of mass to ensure a trim able and …
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