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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.
461

Determining aerodynamic properties of sports balls in situ

Kensrud, Jeffrey Ryan. January 2010 (has links) (PDF)
Thesis (M.S. in mechanical engineering)--Washington State University, August 2010. / Title from PDF title page (viewed on July 30, 2010). "Department of Mechanical and Materials Engineering." Includes bibliographical references (p. 105-108).
462

The physiological effects of drafting in runners

Arnett, Mary S. January 2002 (has links)
Thesis (M.S.)--University of Wisconsin--La Crosse, 2002. / Includes bibliographical references.
463

Evalution [i.e., evaluation] of V-22 tiltrotor handling qualities in the instrument meteorological environment

Trail, Scott B. January 1900 (has links) (PDF)
Thesis (M.S.) -- University of Tennessee, Knoxville, 2006. / Title from title screen (viewed Nov. 13, 2007). Thesis advisor: Robert B. Richards. Vita. Includes bibliographical references (p. 40).
464

A study of direct-current surface discharge plasma for a Mach 3 supersonic flow control

Shin, Jichul, January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.
465

Numerical study of wingtip shed vorticity reduction by wing boundary layer control

Posada, Jose Alejandro. January 1900 (has links)
Thesis (Ph. D.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains xix, 167 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 148-151).
466

An investigation of the effects of spanwise wall oscillation on the structure of a turbulent boundary layer /

Trujillo, Steven Mathew, January 1999 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 200-205). Available also in a digital version from Dissertation Abstracts.
467

The design and testing of a horizontal axis wind turbine with sailfoil blades

Taylor, D. January 1985 (has links)
The work contained in this thesis covers the design, development and testing of a horizontal axis wind turbine (HAWT) with Sailfoil blades. Included is a brief history of wind turbine technology, its revival, a review of current wind energy developments and a literature survey of previous work on wind turbines with sail type blades. The Sailfoil blade consists of a framework of a leading edge D spar and a rigid trailing edge spar over which is stretched a fabric sock, forming a wing-like surface. The aerodynamic performance theories of HAWTs are described, as is the aerodynamic, structural and mechanical design of a 4 metre diameter, 3 bladed HAWT with Sailfoil blades. A wind turbine test facility was designed and developed for free air testing of wind turbines and is described. Free air tests were carried out on the Sailfoil wind turbine on the test facility to obtain power coefficient versus tip speed ratio curves and power versus wind speed curves for the wind turbine. These are presented and compared to predicted values.
468

Ram-jet combustion based on shock/flame interaction

Edwards, J. A. January 1983 (has links)
An experimental investigation into the effects of shock/wake and shock/flame interaction on the base pressure of axisymmetric bodies at Mach 2 has been carried out. This investigation has determined the effects of various forms of shock generator (axisymmetric cowls, twodimensional wedges and 'delta' wings) on the base pressure. Shock waves generated by over-expanding the airflow in an open-jet wind tunnel have been used to determine the effect of shock strength on the base pressure of an axisymmetric fuel injector. Both peripheral bleed and axial bleed of hydrogen fuel have been examined and the effect of shock compression on the resulting flame has been determined. In the axial bleed case nitrogen and hydrogen bleed without combustion has also been examined. The effect of varying the airflow stagnation temperature has also beeninvestigated. It is demonstrated herein that there is a distinct shock/wake interaction position that maximises the base pressure, that with interaction at this optimal position the static pressure rise across the shock wave can be communicated in full to the base of the centrebody, and that favourable aerodynamic interference between the wake and a cowl of 50 convergent-divergent internal section can give rise to a net drag reduction. The shock/wake and shock/flame experiments demonstrate that a significant base thrust can be generated, however, the fuel efficiency decreases with increasing shock strength. It is shown that the fuel specific impulse is a function of shock strength, interaction position and bleed mode (peripheral or axial). The onset of boundary layer separation due to the adverse pressure gradient encountered when the base pressure is high appears to limit the useful addition of wake combustion. Finally, it is demonstrated that the base pressure, with and without combustion, is only a weak function of airflow stagnation temperature.
469

Crosswind aerodynamics of sports utility vehicles

Chadwick, Andrew January 1999 (has links)
Crosswind gusts have a continuous influence on the ride and handling of road vehicles. At low speeds the effect is negligible but as both car and wind speeds increase there is a reduction in refinement, ride quality is degraded and it becomes tiring to drive. Future environmental legislation concerning the reduction of carbon dioxide emissions will lead to a lighter road vehicle and a corresponding increase in crosswind sensitivity. The aerodynamicist's approach to understanding the fluid flow around a vehicle when subjected to a crosswind has conventionally been through steady state model tests where aerodynamic force and moment data are taken for different yaw angles. The accuracy of this data has previously been questioned because of a lack of simulation of the transient nature of the crosswind gust. Additionally, although force and moment data can tell the aerodynamicist which are the principle loads influencing a vehicles response in a crosswind, they fail to identify the specific regions on the vehicle that contribute to these aerodynamic loads. This can only be achieved by pressure mapping the model surface and although such a technique has been employed during steady state tests, no research has been presented with the correct modeling of the transient crosswind gust. To gain an initial understanding of the complex time dependent and separated flow fields around bluff vehicles, such as sports utility vehicles, when subjected to a crosswind, aerodynamic force, moment and surface pressure data of simple geometric shapes has been collected on the Cranfield crosswind track facility. Steady state data has been obtained from conventional wind tunnel tests and compared with the transient data. Unique pressure animations identify the growth and collapse of vortices on the leeward face as the primary transient characteristic and which produce peak aerodynamic yawing moments up to double that seen in the steady state.
470

Modelling the wake flow of large wind turbines

Green, Duncan R. R. January 1986 (has links)
To provide power on a national scale, a large number of windmills will have to be deployed in wind farms or arrays because the output of individual machines is relatively small. Within an array, some windmills will be faced with the wakes generated by others. This interaction leads to a loss of power relative to upwind turbines and changes in the wind loading across the turbine blades.

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