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On the development of an improved lift-constrained aerodynamic optimization algorithm.Billing, Laura K. January 2006 (has links)
Thesis (M.A. Sc.)--University of Toronto, 2006. / Source: Masters Abstracts International, Volume: 45-03, page: 1546.
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Surface flow measurements of supersonic impinging microjetsDavy, Charney A. Alvi, Farrukh S. January 2003 (has links)
Thesis (Ph. D.)--Florida State University, 2003. / Advisor: Dr. Farrukh S. Alvi, Florida State University, FAMU - FSU College of Engineering, Dept. of Mechanical Engineering. Title and description from dissertation home page (Aug. 27, 2004). Includes bibliographical references.
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Determination of Drag and Lift Coefficients for a Spinning BaseballParekh, M. B. 01 May 1972 (has links)
Few experiments have been carried out in the past to deter mine the effect of the lift and the drag forces on the trajectory of a ball used in any game. In a baseball game, it was reported that sometimes the ball took a sharp turn aburptly in the region of 15 to 20 feet from the home plate. This indicated a sudden change of the forces acting on the ball. The principal forces acting w ere as fol lows: 1. Weight of the ball. 2. Drag force acting in the direction parallel to the relative wind. 3. Lift force acting perpendicular to the relative wind.
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Numerical Analysis of a Circulation Control WingBodkin, Luke W 01 December 2020 (has links) (PDF)
The objective of this thesis was to develop an experimental method to research circulation control wings using numerical analysis. Specifically, it is of interest to perform 3D wind tunnel testing on a circulation control wing in the Cal Poly Low Speed Wind Tunnel (CPLSWT). A circulation control wing was designed and analyzed to determine the feasibility of this testing.
This study relied on computational fluid dynamics (CFD) simulations as a method to predict the flow conditions that would be seen in a wind tunnel test. A CFD simulation was created of a wing model in a wind tunnel domain. Due to high computational requirements, reliable 3D CFD results were not obtained. This led to utilizing 2D CFD models to make estimations about the flow conditions that would be encountered in an experimental environment. The 2D CFD model was validated with previous experimental data on circulation control wings and was shown to accurately capture the flow physics. These 2D CFD results were used to create a set of guidelines to help improve the effectiveness of a future wind tunnel test campaign and demonstrate where further design work needs to be done.
The key finding is that it is feasible to perform circulation control testing in the CPLSWT with limitations on the maximum momentum coefficient. Due to internal plenum pressures reaching 66 psi at Cμ=0.35, a limitation should be placed on experimental testing below the choked condition of at Cμ=0.15. This provides a more feasible operating range for the equipment available. The main performance parameter of the airfoil was met with CLMAX=5.01 at Cμ=0.35 which required 0.9 lb/s/m mass flow rate for the 2D model.
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A comprehensive investigation into the supersonic viscous flow about a slender cone at high angle of attack : experimental and theoretical results /Rice, Thomas Stuart January 1980 (has links)
No description available.
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Concurrent Aerodynamic Shape / Cost Design Of Magnetic Levitation Vehicles Using Multidisciplinary Design Optimization TechniquesTyll, Jason Scott 05 August 1997 (has links)
A multidisciplinary design optimization (MDO) methodology is developed to link the aerodynamic shape design to the system costs for magnetically levitated (MAGLEV) vehicles. These railed vehicles can cruise at speeds approaching that of short haul aircraft and travel just inches from a guideway. They are slated for high speed intercity service of up to 500 miles in length and would compete with air shuttle services. The realization of this technology hinges upon economic viability which is the impetus for the design methodology presented here. This methodology involves models for the aerodynamics, structural weight, direct operating cost, acquisition cost, and life cycle cost and utilizes the DOT optimization software. Optimizations are performed using sequential quadratic programming for a 5 design variable problem. This problem is reformulated using 7 design variables to overcome problems due to non-smooth design space. The reformulation of the problem provides a smoother design space which is navigable by calculus based optimizers. The MDO methodology proves to be a useful tool for the design of MAGLEV vehicles. The optimizations show significant and sensible differences between designing for minimum life cycle cost and other figures of merit. The optimizations also show a need for a more sensitive acquisition cost model which is not based simply on weight engineering. As a part of the design methodology, a low-order aerodynamics model is developed for the prediction of 2-D, ground effect flow over bluff bodies. The model employs a continuous vortex sheet to model the solid surface, discrete vortices to model the shed wake, the Stratford Criterion to determine the location of the turbulent separation, and the vorticity conservation condition to determine the strength of the shed vorticity. The continuous vortex sheet better matches the mechanics of the flow than discrete singularities and therefore better predicts the ground effect flow. The predictions compare well with higher-order computational methods and experimental data. A 3-D extension to this model is investigated, although no 3-D design optimizations are performed.
NOTE: An updated copy of this ETD was added on 05/29/2013. / Ph. D.
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Aircraft departure resistance prediction using structured singular valuesYork, Brent W. 21 July 2009 (has links)
Research has been conducted in recent years to determine the dynamic behavior of aircraft in unusual flight attitudes, particularly at very high angle-of-attack or post-stall conditions. The possibility that future advanced fighter aircraft will have the ability to perform controlled maneuvers at such attitudes is indicated by the current military aircraft flying qualities specification, MIL-STD-1797. As it becomes more important to understand the dynamics of aircraft at such flight conditions, the need for a meaningful and useful assessment of aircraft departure resistance in varying attitudes will increase proportionally. This thesis surveys some of the measures of departure susceptibility currently in use and examines a candidate for a new departure resistance criterion which offers distinct advantages over the traditional metrics.
The new departure resistance criterion, called DP<sub>SSV</sub> is essentially a measure of how much uncertainty the nominally stable plant can tolerate before being driven unstable. DP<sub>SSV</sub> is calculated using structured singular values. In this thesis, DP<sub>SSV</sub> is calculated over various flight conditions for a typical high-performance fighter aircraft which is represented by a full six degree of freedom, nonlinear simulation. The results are compared with those obtained by using a traditional departure susceptibility metric and by examining the eigenvalues of linearized forms of the aircraft model.
The new criterion DP<sub>SSV</sub> is shown to provide more information about the departure susceptibility of an aircraft than C<sub>ηβ<sub>DYN</sub></sub> traditional metric, and to produce results in good agreement with the eigenvalue analysis of the stability of the aircraft for the conditions studied. The interpretation of DP<sub>SSV</sub> is discussed, and suggestions for future investigation are also presented. / Master of Science
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An experimental study of automotive underbody diffusersJowsey, Lydia January 2013 (has links)
Aerodynamics has always been a driving force in motorsport and road vehicle design and development, and continues to play an important role. A significant advancement in race car aerodynamics was the development of the vehicle underbody to produce downforce, in particular the implementation of the diffuser. This thesis concentrates on the performance flow mechanisms found in simple rear diffusers commonly seen in motorsport applications. There is little published work on these mechanisms, especially the influence of the more commonly used multiple-channel diffusers.
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Acoustic replication in smart structure using active structural/acoustic controlGriffin, Steven F. 12 1900 (has links)
Dissertation made openly available per email from author, 7/22/2016.
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Interactions of coherent structures in annular jets劉國強, Lau, Kwok-keung. January 1991 (has links)
published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy
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