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 29 for “"Induced Drag"”.
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Optimum Spanloads Incorporating Wing Structural Considerations And Formation Flying
The classic minimum induced drag spanload is not necessarily the best choice for an aircraft. For a single aircraft configuration, variations from the elliptic, minimum drag optimum load distribution can produce wing weight savings that result in airplane performance benefits. For a group of …
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A simplified vortex sheet roll-up method for formation flight
… of the roll-up of a wake on the benefits in induced drag and rolling moment experienced by a close formation of two elliptically loaded wings. The roll-up of the leading wake is computed in the Trefftz plane using a linear vorticity panel method. A smoothing parameter as well as a truncation …
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The effects of atmospheric turbulence on fuel consumption in extended formation flight
… recently proposed as a method for reducing the induced drag of commercial aircraft. However, induced drag savings are not necessarily directly indicative of fuel savings. In a realistic environment, atmospheric turbulence will continuously perturb the formation’s aircraft and their wakes. As a …
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The Design and Experimental Optimization of a Wingtip Vortex Turbine for General Aviation Use
<p>A wingtip vortex turbine (WVT) is an induced drag reduction device that straightens the vortex flow (reducing induced drag and wake turbulence) and also produces a thrust force component. The WVT also has the advantage of extracting the rotational energy of the vortex to turn a generator, which …
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Experimental Characterization of Additively Manufactured Multi-Feather Wingtip Devices
… engineering objective was to reduce the induced drag as a means to improve the fuel efficiency via these experimental wingtips. An associated secondary objective was to establish a method for manufacturing complex structures suitable for wing tunnel testing. A manufacturing technique that …
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Hydrofoil shape optimization by gradient methods
… lifting line theory was used to account for induced drag and downwash at the leading edge of the foil. Strip theory was used to extend the two-dimensional wave drag solutions to three dimensions for high aspect ratio foils. A semi-empirical correction was added to account for viscous drag. …
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An experimental study of the aerodynamic characteristics of a wing in close proximity to a moving ground plane
… in the lift-curve slope and a reduction in induced drag, which resulted in an increase in the lift-drag ratio.
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Understanding the Structure of Wing Tip Vortices of Bio-Inspired Winglets
… analyzed to determine an approximation for the induced drag. The wing with the bio-inspired winglet generated the highest lift at a given angle of attack, as reported previously. At higher angles of attack, the wing with the conventional winglet had the minimum induced drag. All three wing …
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Aerodynamic and Structural Design of a Winglet for Enhanced Performance of a Business Jet
… offering the best compromise between induced drag reduction, profile drag increase and weight increase due to the winglet structure and necessary wing structural reinforcement was selected. More refined analysis was performed for that winglet with Reynolds averaged Navier-Stokes …
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Spray cooling applications for alternative energy vehicles
… driving up the costs and reduce range due to the induced drag. Here we examine utilizing water to spray onto the heat exchangers to increase performance, allowing a decrease in surface area required for heat exchangers in alternative fuel source vehicles. The scalable and optimized super …
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The Investigation of an Inboard-Winglet Application to a Roadable Aircraft
… its effective aspect ratio and resulting in an induced-drag decrease. With an application of the new wing concept, the Pegasus II performance is comparable to other general aviation aircraft.
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A Study of the Design of Adaptive Camber Winglets
… that any winglet flap deflections increased induced drag and parasitic drag, thus decreasing efficiency for steady level flight conditions. Positive winglet flap deflection at higher lift conditions may increase efficiency, but the validity of the vortex lattice method results for these …
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Optimal and on-board near-optimal midcourse guidance
… - Point mass model with approximation of the induced-drag; - Energy model. One of the major results in this study is that the reduced-order models are not accurate enough to approximate the optimal trajectories and so are of limited use as reference trajectories in an on-board scheme. Thus, …
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The effects of turbulence on the measurements of five-hole probes
… techniques to quantify these turbulence-induced errors and by developing a novel method of predicting the response of a five-hole probe to turbulence. A few studies have attempted to quantify turbulence-induced errors in five-hole probe measurements but they were limited by their …
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Dual Mode Macro Fiber Composite-Actuated Morphing Tip Feathers for Controlling Small Unmanned Aircraft
… a traditional rectangular wing, yielded 73% less induced drag and generated proverse yaw. However, the MFC feathers alone, in the configuration tested, did not produce enough roll authority to feasibly control an aircraft.
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Drag Measurements on an Ellipsoidal Body
A drag study was conducted on an oblate ellipsoid body in the Virginia Tech Stability Wind Tunnel. Two-dimensional wake surveys were taken with a seven-hole probe and an integral momentum method was applied to the results to calculate the drag on the body. Several different model configurations …
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Multidisciplinary Design Optimization of a Strut-Braced Wing Aircraft
… to be reduced without incurring a transonic wave drag penalty. The reduced wing sweep allows a larger percentage of the wing area to achieve natural laminar flow. Additionally, tip-mounted engines can be used to reduce the induced drag. The MDO approach helps the designer achieve the best …
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Shape and Structural Optimization of Flapping Wings
… is used to better approximate the effects of the induced drag on the wing. A multi-objective optimization approach is used since more than one aspect is considered in flapping wing design. The the epsilon-constraint approach is used to calculate the Pareto optimal solutions that maximize the …
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Rotor Wakes; Formations, Interactions, and Design
… a vortex filament in its place. The minimum induced loss (MIL) rotor has long served as the conventional baseline in rotor design. However, with the rise of DEP configurations, blown-wing systems, urban air mobility, and the widespread use of drones in populated environments, rotor design …
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