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 55 for “"Unsteady Aerodynamic"”.
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Unsteady Aerodynamic and Aeroelastic Analysis of Flapping Flight
The unsteady aerodynamic and aeroelastic analysis of flapping flight under various kinematics and flow parameters is presented in this dissertation. The main motivation for this study arises from the challenges facing the development of micro air vehicles. Micro air vehicles by requirement are …
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Analytical Unsteady Aerodynamic Models for Horizontal Axis Wind Turbines
This thesis describes the development of unsteady aerodynamic models of wind turbines within the framework of blade element momentum theory. The main purpose is to build analytical models, and test them against available wind tunnel and field test data. The unsteady wake is modeled using vortex …
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Time domain modeling of unsteady aerodynamic forces on a flapping airfoil
… develop a versatile and fast 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 …
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The longitudinal dynamics of a rigid aircraft including unsteady aerodynamic effects
… problems of importance in the domain of applied aerodynamics and control, a great effort has been given to setting up the physics of unsteady aerodynamics and its effects on the aircraft longitudinal modes. Numerical examples are given for both the two-dimensional and three-dimensional rigid …
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Reynolds number effects on the unsteady aerodynamic behavior of an NACA 0012 airfoil
Thesis: M.S., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 1986
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Identification of an Unsteady Aerodynamic Model up to High Angle of Attack Regime
… by Remez exchange algorithm to extract the aerodynamic characteristics responses to the programmed motions from the resampled measurements. These data reduction procedures are also illustrated through examples. The results obtained from the harmonic oscillatory tests are then illustrated and …
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Unsteady Aerodynamic/Hydrodynamic Analysis of Bio-inspired Flapping Elements at Low Reynolds Number
… lifting and flow control mechanisms generated by unsteady flapping body motion. Understanding and characterizing the aerodynamic phenomena associated with the unsteady motion is vital to predict the unsteady fluid loads generated, to implement control methodologies, and to assess the dynamic …
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High-Fidelity Modeling of eVTOL Rotor Unsteady Aerodynamic and Aeroacoustic Response to Time-Harmonic Gust
… Among the various noise sources, the aerodynamic and acoustic response of rotors to unsteady inflow represents a major uncertainty in community-noise assessment and certification. This thesis investigates the aerodynamic and aeroacoustic behavior of a representative eVTOL rotor …
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Measurement of unsteady aerodynamic characteristics of a subscale aerobatic aircraft in high angle-of-attack maneuvers
… trajectory plots, time histories and aircraft aerodynamic coefficient data. These plots showed unsteady aerodynamic effects exhibited by the aircraft. Among these results was one version of wing rock, where given a certain aircraft configuration with constant control surface inputs, the …
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An Investigation of Unsteady Aerodynamic Multi-axis State-Space Formulations as a Tool for Wing Rock Representation
… of the present research is to investigate unsteady aerodynamic models with state equation representations that are valid up to the high angle of attack regime with the purpose of evaluating them as computationally affordable models that can be used in conjunction with the equations of …
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Unsteady Aerodynamics of Deformable Thin Airfoils
Unsteady aerodynamic theories are essential in the analysis of bird and insect flight. The study of these types of locomotion is vital in the development of flapping wing aircraft. This paper uses potential flow aerodynamics to extend the unsteady aerodynamic theory of Theodorsen and Garrick (which …
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Adaptive, suboptimal and nonlinear control of an aeroelastic system
… adaptive control system is derived. Quasi-steady aerodynamic model is used for the output feedback modular adaptive control system. For the synthesis of the adaptive controller, it is assumed that only pitch angle and plunge displacement are measured. The control system consists of an …
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Vibration and Aeroelasticity of Advanced Aircraft Wings Modeled as Thin-Walled Beams--Dynamics, Stability and Control
… concept of indicial functions is used to develop unsteady aerodynamic model, which broadly encompasses the cases of incompressible, compressible subsonic, compressible supersonic and hypersonic flows. State-space conversion of the indicial function based unsteady aerodynamic model is also …
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Experimental Investigation of the Active Flow Control on a Two-Dimensional Wind Turbine Airfoil
<p>Wind turbine blades experience unsteady aerodynamic loading under various off-design conditions. The fatigue loading reduces the operational time of the wind turbine hence leads to an increase in the Cost of Energy (CoE) of the wind power. In this study, active flow control with unsteady blowing …
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Parametric Viscous Analysis of Gust Interaction with Stationary and Elastically Mounted Airfoil
… interaction of SD7003 airfoil with non-uniform, unsteady incoming flow. The study is focused on the low-Re number unsteady flows typical of MAV applications in which a gust encounter can induce a particularly significant aerodynamic and aeroelastic response. Efficient source models are developed …
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Flutter and Forced Response of Turbomachinery with Frequency Mistuning and Aerodynamic Asymmetry
… time-linearized Navier-Stokes solver. Steady and unsteady flow parameters including local work on the blade surfaces are investigated. It was found that global local work monotonically became more unstable on the pressure side due to the flow rollback effect. The local work on the suction side …
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Development of a data reduction method for a high frequency angle probe
… angle probe. The angle probe is designed for unsteady aerodynamic measurements in transonic cryogenic wind tunnels. The probe measures time-resolved total pressure, static pressure, angle of attack, and yaw angle from readings of four pressure transducers. The unique feature of this probe, as …
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Investigations into rapid aeroelastic stability estimation in turbomachines for preliminary design
… To date, these preliminary design tools include aerodynamic efficiency and structural durability considerations. However, the aeroelastic stability of turbomachinery stages is traditionally treated very late in the design process after the end of the automated preliminary design cycle. This …
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Sensitivity analysis of wing aeroelastic responses
… flow is examined using a state-space unsteady aerodynamic representation. The sensitivity of the flutter speed of the typical section with respect to its mass and stiffness parameters, namely, mass ratio, static unbalance, radius of gyration, bending frequency and torsional frequency …
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