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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
161

Effects of a Bell-Shaped Lift Distribution on an Oblique Flying Wing and its Impact on Aerodynamic Performance

Deslich, Joshua 22 June 2020 (has links)
No description available.
162

The Finest Entertainment: Conscious Observation on Film in Adaptations of Henry James' The Portrait of a Lady, The Wings of the Dove, and Washington Square

Bailey, Rachael Decker 15 March 2006 (has links) (PDF)
The works of Henry James are renowned for their dense sub-text and the manner in which he leaves his reader to elucidate much of his meaning. In the field of adaptation theory, therefore, James presents somewhat of a problem for the film adaptor: how does one convey on screen James' delicate implications, which are formative to the text without actually existing on the printed page? This project not only works to answer that question, but it also addresses a more serious question: what does adaptation have to offer to the student of literature? In the case of Henry James, the film adaptations of his novels expose the trope of voyeurism which functions as one of the central operative mechanisms in the novels, allowing both authorial omniscience into the minds and lives of the characters, as well as the creation of a voyeuristic character through whose perceptions the reader's knowledge is filtered. In examining recent film adaptations of The Portrait of a Lady. The Wings of the Dove, and Washington Square, it becomes apparent that the key to adapting James is careful attention to this trope of voyeurism, which ultimately becomes more important to a successful adaptation (an adaptation which most closely reproduces James' observations and biases rather than those of the director) than exact fidelity to the plot itself. With these considerations in mind, I have indicated that Jane Campion's 1996 adaptation of The Portrait of a Lady most successfully achieves James' purposes, highlighting both the on-screen voyeurism of Ralph Touchett, then using techniques (lighting, camera angles, editing, sound) to similarly construct the viewer as voyeur. Agniezka Holland's Washington Square, however, ignores James' careful positioning of Catherine Sloper as an object of visual amusement to her father and creates an insipid film that plays the drama as a mercantile transaction gone awry. On the opposite end of the spectrum, Iain Softley's The Wings of the Dove bloats the construct of viewer as voyeur into ineffectuality through his use of full nudity to capture the eye of the audience, ensuring that the film's images, rather than its story, are all that is remembered.
163

Sympathetic Observations: Widowhood, Spectatorship, and Sympathy in the Fiction of Henry James

Gordon-Smith, George Michael 12 June 2008 (has links) (PDF)
This thesis explores the roles of widowhood and sympathy in Henry James's short and long fiction. By the time James established himself as a writer of fiction, the culture of sentiment and its formation of sympathetic identification had become central to American and British writers. Critically, however, sympathy in James's fiction has been overlooked because he chose to write about rich expatriates and European nobility. James's pervasive use of widowed characters in his fiction suggests the he too participated in the same aesthetic agenda as William Dean Howells and George Eliot to evoke sympathy in their readers as a means of promoting class unity. In this thesis I show how James's use of widowed characters places him in the same sympathetic tradition as Howells and Eliot not by eliciting sympathy for themselves, but, rather, by awakening a sympathetic response from his readers for his protagonists seeking love. In chapter one I explore why James may have used so many widowed characters in his fiction. I cite the death of his cousin Minny Temple as a defining moment in his literary career and argue that he may have experienced an "emotional widowhood" after her early death. I also discuss the role of widows in his short fiction, which I suggest, is different from the role of widows in his novels. This chapter is biographical, yet provides important background for understanding why, more than any other author, James's fiction is replete with widowed characters. Chapter two explains the culture of sentiment of which James has been excluded. It explores the theories of David Hume and Adam Smith and their influence on the aesthetic principles defining Howells and Eliot's work. In this chapter I contend that James is indeed part of this sentimental tradition despite his renunciation of sentiment in his fiction because he tried to promote sympathy among his readers through his widowed characters. In chapter three I do close readings of The Portrait of a Lady (1881) and The Wings of the Dove (1902) and argue that these two texts best represent James's attempt at sympathetic writing.
164

Wings 7 blue and cultural understanding

Larsson, Annah, Karlsson, Lucia January 2009 (has links)
The aim of this dissertation is to investigate how culture is represented in the Wings 7 blue textbook and workbook and what implications this may have on learners’ cultural understanding. The research questions are: How is culture represented in the textbook and workbook Wings 7 blue?, and What cultural understanding is promoted through the task design of the learning material Wings 7 blue?The analysis of the learning material draws on the theoretical framework of the Swedish researcher Ulrika Tornberg. The result of our analysis, and first research question, displays that the main focus of the cultural content in the Wings 7 blue textbook is on the mainstream national culture of Britain, typical British behavior, and linguistic readiness.Cultural understanding may be seen as either general cultural understanding, based on Tornberg’s two first perspectives, or as intercultural understanding which can be found in Tornberg’s third and final perspective. The result of the analysis of the tasks shows that both types of cultural understanding are promoted in the workbook, but the possibility for learners to develop their own intercultural understanding is limited, which is the answer to our second research question. This leads to the conclusion that the learning material, by itself, does not cover the complete aim for cultural understanding in the National Syllabus.One might argue that the material should only be seen as a complement to the other tools of the teacher, who can compensate for any missing information in his or her communication with the class. However, according to the large National survey for English, teachers of English mostly use published learning materials and tend to trust that these correspond to the aims of the steering documents.
165

Crossflow stability and transition experiments in a swept-wing flow

Dagenhart, J. Ray 08 August 2007 (has links)
An experimental examination of crossflow instability and transition on a 45° swept wing is conducted in the Arizona State University Unsteady Wind Tunnel. The stationary-vortex pattern and transition location are visualized using both sublimating-chemical and liquid-crystal coatings. Extensive hot-wire measurements are conducted at several measurement stations across a single vortex track. The mean and travelling-wave disturbances are measured simultaneously. Stationary-crossflow disturbance profiles are determined by subtracting either a reference or a span-averaged velocity profile from the mean-velocity data. Mean, Stationary-crossflow, and travelling-wave velocity data are presented as local boundary-layer profiles and as contour plots across a single stationary-crossflow vortex track. Disturbance-mode profiles and growth rates are determined. The experimental data are compared to predictions from linear stability theory. Comparison of measured and predicted pressure distributions shows that a good approximation of infinite swept-wing flow is achieved. A fixed-wavelength vortex pattern is observed throughout the visualization range. The theoretically-predicted maximum-amplified vortex wavelength is found to be approximately 25% larger than the observed wavelength. Linear-stability computations for the dominant stationary-crossflow vortices show that the N-factors at transition ranged from 6.4 to 6.8. The mean-velocity profiles vary slightly across the stationary-crossflow vortex at the first measurement station. The variation across the vortex increases with downstream distance until nearly all of the profiles become highly-distorted S-shaped curves. Local stationary-crossflow disturbance profiles having either purely excess or deficit values develop at the upstream measurement stations. Further downstream the profiles take on crossover shapes not anticipated by the linear theory. The maximum streamwise stationary-crossflow velocity disturbances reach +20% of the edge velocity just before transition. The travelling-wave disturbances have single lobes at the upstream measurement stations as expected, but further downstream double-lobed travelling-wave profiles develop. The maximum disturbance intensity remains quite low until just ahead of the transition location where it suddenly peaks at 0.7% of the edge velocity and then drops sharply. The travelling-wave intensity is always more than an order of magnitude lower than the stationary crossflow-vortex strength. The mean streamwise-velocity contours are nearly flat and parallel to the model surface at the first measurement station. Further downstream, the contours rise up and begin to roll over like a wave breaking on the beach. The stationary-crossflow contours show that a plume of low-velocity fluid rises near the center of the wavelength while high-velocity regions develop near the surface at each end of the wavelength. There is no distinct pattern to the low-intensity travelling-wave contours until a short distance upstream of the transition location where the travelling-wave intensity suddenly peaks near the center of the vortex and then falls abruptly. The experimental disturbance-mode profiles agree quite well with the predicted eigenfunctions for the forward measurement stations. At the later stations, the experimental mode profiles assume double-lobed shapes with maxima above and below the single maximum predicted by the linear theory. The experimental growth rates are found to be less than or equal to the predicted growth rates from the linear theory. Also, the experimental growth rate curve oscillates over the measurement range whereas the theoretically-predicted growth rates decrease monotonically. / Ph. D.
166

The Aerodynamics of Low Sweep Delta Wings

Rullan, Jose Miguel 05 December 2008 (has links)
The aerodynamics of wings with moderately swept wings continues to be a challenging and important problem due to the current and future use in military aircraft. And yet, there is very little work devoted to the understanding of the aerodynamics of such wings. The problem is that such wings may be able to sustain attached flow next to broken-down delta-wing vortices, or stall like two-dimensional wings, while shedding vortices with generators parallel to their leading edge. To address this situation we studied the flow field over diamond-shaped planforms and sharp-edged finite wings. Possible mechanisms for flow control were identified and tested. We explored the aerodynamics of swept leading edges with no control. We presented velocity and vorticity distributions along planes normal and parallel to the free stream for wings with diamond shaped planform and sharp leading edges. We also presented pressure distributions over the suction side of the wing. Results indicated that in the inboard part of the wing, an attached vortex can be sustained, reminiscent of delta-wing type of a tip vortex, but further in the outboard region 2-D stall dominated even at 13° AOA and total stall at 21° AOA. To explore the unsteady flow field and the effectiveness of leading-edge control of the flow over a diamond-planform wing at 13° AOA, we employed Particle Image Velocimetry (PIV) at a Reynolds number of 43,000 in a water tunnel. Our results indicated that two-D-like vortices were periodically generated and shed. At the same time, an underline feature of the flow, a leading edge vortex was periodically activated, penetrating the separated flow, eventually emerging downstream of the trailing edge of the wing. To study the motion and its control at higher Reynolds numbers, namely 1.3 x 106 we conducted experiments in a wind tunnel. Three control mechanisms were employed, an oscillating mini-flap, a pulsed jet and spanwise continuous blowing. A finite wing with parallel leading and trailing edges and a rectangular tip was swept by 0°, 20°, and 40° and the pulsed jet employed as is control mechanism. A wing with a diamond-shaped-planform, with a leading edge sweep of 42°, was tested with the mini-flap. Surface pressure distributions were obtained and the control flow results were contrasted with the no-control cases. Our results indicated flow control was very effective at 20° sweep, but less so at 40° or 42°. It was found that steady spanwise blowing is much more effective at the higher sweep angle. / Ph. D.
167

Analysis of the vortical flow around a 60 degree delta wing with vortex flap

Sung, Bongzoo January 1985 (has links)
Subsonic wind tunnel investigations were conducted on a 60° swept, flat plate, delta wing with a leading edge vortex flap. The pressure distributions were measured over a range of angles of attack starting from zero to 40° in 5° interval and flap deflection angles from zero to 45° with 5° increments at a Reynolds number of about 2.14 x 10‘ based on the root chord. The flow visualization experiments were performed from zero degree to the stall angle, with ten different flap deflection angles at the same Reynolds number. The mean flow field was measured at angles of attack l0° and 15° with the flap deflection angles of l0° and 30° at a Reynolds number of about 1.50 x 10°. The experimental results shows that the leading edge vortex flap is an effective means to control the vortex flow over a delta wing. The optimum flap deflection angles were found where the primary vortex was confined to the leading edge vortex flap, thus producing a thrust on the flap. It was found that flap deflection could be used to restore a vortex flow from burst vortex condition. / Ph. D. / incomplete_metadata
168

Aerodynamic pitch-up of cranked arrow wings: estimation, trim, and configuration design

Benoliel, Alexander M. 10 November 2009 (has links)
Low aspect ratio, highly-swept cranked arrow wing planforms are often proposed for high-speed civil transports. These wing planforms offer low supersonic drag without suffering greatly from low lift/drag ratios in low-speed flight. They can, however, suffer from pitch-up at modest angles of attack (as low as 5°) during low-speed flight due to leading edge vortex influence, flow separation and vortex breakdown. The work presented here describes an investigation conducted to study past research on the longitudinal aerodynamic characteristics of highly-swept cranked wing planforms, the development of a new method to estimate pitch-up of these configurations, and the applications of this new method to the analysis of tail designs for trim at high lift coefficients. The survey of past research placed emphasis on 1) understanding the problem of pitch-up, 2) ascertaining the effects of leading and trailing edge flaps, and 3) determining the benefits and shortfalls of tail, tailless, and canard configurations. The estimation method used a vortex lattice method to calculate the inviscid flow solution. Then, the results were adjusted to account for flow separation on the outboard wing section by imposing a limit on the equivalent 2-D sectional lift coefficient. The new method offered a means of making low cost estimates of the nonlinear pitching moment characteristics of slender, cranked arrow wing configurations with increased accuracy compared to conventional linear methods. Numerous comparisons with data are included. The new method was applied to analyze the trim requirement of slender wing designs generated by an aircraft configuration optimization and design program. The effects of trailing edge flaps and horizontal tail on the trimmed lift coefficient was demonstrated. Finally, recommendations were made to the application of this new method to multidisciplinary design optimization methods. / Master of Science
169

Optimization of composite box-beam structures including effects of subcomponent interaction

Ragon, Scott Alan 16 June 2009 (has links)
Minimum mass designs are obtained for a simple box beam structure subject to bending, torque and combined bending/torque load cases. These designs are obtained subject to point strain and linear buckling constraints. The present work differs from previous efforts in that special attention is payed to including the effects of subcomponent panel interaction in the optimal design process. Two different approaches are used to impose the buckling constraints. When the global approach is used, buckling constraints are imposed on the global structure via a linear eigenvalue analysis. This approach allows the subcomponent panels to interact in a realistic manner. The results obtained using this approach are compared to results obtained using a traditional, less expensive approach, called the local approach. When the local approach is used, in-plane loads are extracted from the global model and used to impose buckling constraints on each subcomponent panel individually. In the global cases, it is found that there can be significant interaction between skin, spar, and rib design variables. This coupling is weak or nonexistent in the local designs. It is determined that weight savings of up to 7% may be obtained by using the global approach instead of the local approach to design these structures. Several of the designs obtained using the linear buckling analysis are subjected to a geometrically nonlinear analysis. For the designs which were subjected to bending loads, the innermost rib panel begins to collapse at less than half the intended design load and in a mode different from that predicted by linear analysis. The discrepancy between the predicted linear and nonlinear responses is attributed to the effects of the nonlinear rib crushing load, and the parameter which controls this rib collapse failure mode is shown to be the rib thickness. The rib collapse failure mode may be avoided by increasing the rib thickness above the value obtained from the (linear analysis based) optimizer. It is concluded that it would be necessary to include geometric nonlinearities in the design optimization process if the true optimum in this case were to be found. / Master of Science
170

Integrated multi-disciplinary design of a sailplane wing

Strauch, Gregory J. 14 November 2012 (has links)
The objective of this research is to investigate the techniques and payoffs of integrated aircraft design. Lifting line theory and beam theory are used for the analysis of the aerodynamics and the structures of a composite sailplane wing. The wing is described by 33 - 34 design variables which involve the planform geometry, the twist distribution, and thicknesses of the spar caps, spar webs, and the skin at various stations along the wing. The wing design must satisfy 30 â 31 aeroelastic, structural, aerodynamic, and performance constraints. Two design procedures are investigated. The first, referred to as the iterative, sequential procedure, involves optimizing the aerodynamic design for maximum average cross-country speed at E1 constant structural weight, and then optimizing the the structural design of the resulting wing geometry for minimum weight. This value is then used in another aerodynamic optimization, and the process continues iteratively until the weight converges. The other procedure, the integrated one, simultaneously optimizes the aerodynamic and the structural design variables for either maximum average cross-country speed or minimum weight. The integrated procedure was able to improve the value of the objective function obtained by the iterative procedure in all cases. This shows The objective of this research is to investigate the techniques and payoffs of integrated aircraft design. Lifting line theory and beam theory are used for the analysis of the aerodynamics and the structures of a composite sailplane wing. The wing is described by 33 - 34 design variables which involve the planform geometry, the twist distribution, and thicknesses of the spar caps, spar webs, and the skin at various stations along the wing. The wing design must satisfy 30 â 31 aeroelastic, structural, aerodynamic, and performance constraints. Two design procedures are investigated. The first, referred to as the iterative, sequential procedure, involves optimizing the aerodynamic design for maximum average cross-country speed at E1 constant structural weight, and then optimizing the the structural design of the resulting wing geometry for minimum weight. This value is then used in another aerodynamic optimization, and the process continues iteratively until the weight converges. The other procedure, the integrated one, simultaneously optimizes the aerodynamic and the structural design variables for either maximum average cross-country speed or minimum weight. The integrated procedure was able to improve the value of the objective function obtained by the iterative procedure in all cases. This shows that definite benefits can be gained from taking advantage of aerodynamic/structural interactions during the design process. / Master of Science

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