Open Access. Powered by Scholars. Published by Universities.®
- Institution
- Keyword
-
- Navier-Stokes equations (2)
- Acoustic loading (1)
- Airplanes (1)
- Buckled structures (1)
- Cavities (1)
-
- Channel flow (1)
- Computations (1)
- Computer simulation. (1)
- Corn planters (Machines); Doppler radar; (1)
- Engineering design. (1)
- Finite element (1)
- Flow fields (1)
- Flows (1)
- Grid generation (1)
- Hard disks (Computer science). (1)
- Hydrogen fuel (1)
- Hypersonic (1)
- Hypersonic flows (1)
- Integral equation method (1)
- Jet cutting. (1)
- Magnetic disks. (1)
- Mathematical optimization. (1)
- Murman-Cole type (1)
- Oscillations (1)
- Piezoelectric transducers. (1)
- Quality control--Costs--Mathematical models; Manufactures--Quality control--Mathematical models; (1)
- Reynolds number (1)
- Shock layers (1)
- Temperature (1)
- Transonic wing flows (1)
Articles 1 - 13 of 13
Full-Text Articles in Engineering
A Finite Element Formulation For The Large Deflection Random Response Of Thermally Buckled Structures, James Eugene Locke
A Finite Element Formulation For The Large Deflection Random Response Of Thermally Buckled Structures, James Eugene Locke
Mechanical & Aerospace Engineering Theses & Dissertations
The effects of temperature and acoustic loading are included in a theoretical finite element large deflection formulation for thin, isotropic plate and beam type structures. Thermal loads are applied as steady-state temperature distributions, and acoustic loads are taken to be stationary and Gaussian with zero mean and uniform magnitude and phase over the surface of the structure. Material properties are considered to be independent of temperature. Also, inplane and rotary inertia terms are assumed to be neglegible, and all inplane edge conditions are taken to be immovable. For the random vibration analysis, cross correlation terms are included.
The nature of …
Numerical Simulation Of Turbulent Flows Past Three-Dimensional Cavities, Shivakumar Srinivasan
Numerical Simulation Of Turbulent Flows Past Three-Dimensional Cavities, Shivakumar Srinivasan
Mechanical & Aerospace Engineering Theses & Dissertations
Computations have been performed to simulate turbulent supersonic, transonic, and subsonic flows past three-dimensional deep, transitional, and shallow cavities. Simulation of these self sustained oscillatory flows has been generated through time accurate solutions of Reynolds averaged full Navier-Stokes equations using the explicit MacCormack scheme. The Reynolds stresses have been modeled, using the Baldwin-Lomax algebraic turbulence model with certain modifications. The computational results include instantaneous and time averaged flow properties everywhere in the computational domain. Time series analyses have been performed for the instantaneous pressure values on the cavity floor. Comparison with experimental data is made in terms of the mean …
Application Of Advanced Grid Generation Techniques For Flow Field Computations About Complex Configurations, Monchai Kathong
Application Of Advanced Grid Generation Techniques For Flow Field Computations About Complex Configurations, Monchai Kathong
Mechanical & Aerospace Engineering Theses & Dissertations
In the computation of flow fields about complex configurations, it is very difficult to construct a boundary-fitted coordinate system. An alternative approach is to use several grids at once, each of which is generated independently. This procedure is called the "multiple grids" or "zonal grids" approach, and its applications are investigated in this study. The method is a conservative approach and provides conservation of fluxes at grid interfaces. The Euler equations are solved numerically on such grids for various configurations. The numerical scheme used is the finite-volume technique with a three-stage Runge-Kutta time integration. The code is vectorized and programmed …
Viscous Shock Layer Analysis Of Hypersonic Flows Over Long Slender Vehicles, Kam-Pui Lee
Viscous Shock Layer Analysis Of Hypersonic Flows Over Long Slender Vehicles, Kam-Pui Lee
Mechanical & Aerospace Engineering Theses & Dissertations
A method for solving the viscous shock-layer equations for hypersonic flows over long slender bodies is presented. The governing equations are solved by employing a spatial-marching implicit finite-difference technique. The two first-order equations, continuity and normal momentum, are solved simultaneously as a coupled set. This method yields a simple and computationally efficient technique.
Flows past hyperboloids and sphere cones with body half angles of five to 35 degrees are considered. The flow conditions included are from high Reynolds numbers at low altitudes to low Reynolds numbers at high altitudes. Detailed comparisons have been made with other predictions and experimental data …
An Analysis Of The Dense Packing Of Disks : A Computer Simulated Approach, Jir-Yih Tsaur
An Analysis Of The Dense Packing Of Disks : A Computer Simulated Approach, Jir-Yih Tsaur
Theses
This thesis is concerned with the analysis of dense packing of hard disks. The Voronoi diagram and the geometric neighbours were first computed. The average number of geometric neighbours of a disk is six. It is thus more efficient to choose structural neighbours from among the geometric neighbours than from among all other disks.
Through the Monte Carlo simulation by Rosato et. al., disk configurations after pouring and subsequent shaking were provided for analysis. The mean number of geometric neighbours and the average coordination number were computed. The angular distribution of the structural neighbours was discussed. The packing fraction increases …
Investigation Of Forces In The Course Of The Water Jet--Work Piece Interaction, Hung-Yuan Li
Investigation Of Forces In The Course Of The Water Jet--Work Piece Interaction, Hung-Yuan Li
Theses
This study is concerned with the dynamic of the interaction between the water jet and the work-piece. The piezoelectric transducer was used to construct an experimental setup. The simultaneous use of the constructed setup and strain gage enables us to validate the experimental procedure. The forces in the impingment zone were measured at different operational conditions. Totally about 400 different combinations of these conditions were tested. It was found that the force is mainly determined by the diameter of the sapphire. The effects of the abrasive size , abrasive flow rate, the diameter of the carbide tube, and the stand-off …
A Feasible Direction Procedure For General Multiple Objective Optimization, Wen-Tsia Liu
A Feasible Direction Procedure For General Multiple Objective Optimization, Wen-Tsia Liu
Dissertations
The Feasible Direction Finding Problem (DFP) of Zoutendijk is adapted to create a general Mathematical Programming (MP) algorithm for treating optimization problems with multiple objective functions. Classically such problems are reduced to standard MP form by converting them to single objective function problems by the use of weighting functions. Unfortunately not all practical problems can be so reduced. Consider the problem of maximizing the strength of a structure. Typically there are several, or even many, failure modes. All active failure modes must be included in the optimal search in such a way that resistance to one active mode can not …
Integral Equation Solution Of The Full Potential Equation For Three-Dimensional, Steady, Transonic Wing Flows, Li-Chuan Chu
Integral Equation Solution Of The Full Potential Equation For Three-Dimensional, Steady, Transonic Wing Flows, Li-Chuan Chu
Mechanical & Aerospace Engineering Theses & Dissertations
An integral equation method for solving the full potential equation has been developed for three dimensional transonic vortex-wing flows. This method is capable of capturing shocks using the Murman-Cole type of finite difference scheme and is capable of predicting accurate and force-free wake shape as well.
Reading the full potential equation as Poisson's equation, the solution for the velocity field has been expressed in terms of an integral equation using Green's theorem. The solution consists of a surface integral of vorticity distribution on the wing and its free-vortex sheets and a volume integral of source distribution within a computational region …
Investigation Of Supersonic Chemically Reacting And Radiating Channel Flow, Mortaza Mani
Investigation Of Supersonic Chemically Reacting And Radiating Channel Flow, Mortaza Mani
Mechanical & Aerospace Engineering Theses & Dissertations
The two-dimensional time dependent Navier-Stokes equations are used to investigate supersonic flows undergoing finite rate chemical reaction and radiation interaction for a hydrogen-air system. The explicit multi-stage finite volume technique of Jameson is used to advance the governing equations in time until convergence is achieved. The chemistry source term in the species equation is treated implicitly to alleviate the stiffness associated with fast reactions. The multi-dimensional radiative transfer equations for a nongray model are provided for a general configuration, and then reduced for a planer geometry. Both pseudo-gray and nongray models are used to represent the absorption-emission characteristics of the …
Advanced Turbulence Closure Models And Their Application To Buoyant And Nonbuoyant Flows, Mohamed Zaki Moustafa
Advanced Turbulence Closure Models And Their Application To Buoyant And Nonbuoyant Flows, Mohamed Zaki Moustafa
Dissertations, Theses, and Masters Projects
In recent years, different approaches for modeling Reynolds stresses have been pursued by various authors. Two different closure schemes, representing two schools of thought, have been selected. The first closure scheme is the k-&\varepsilon& model. The second closure scheme is the level two model. Each group has claimed that the proposed models are an improvement and an advancement over previous models employing the mixing length hypothesis as a closure scheme. Neither group however, has made thorough comparisons between the newly proposed schemes and the most commonly used approach the mixing length hypothesis. The main objective of this paper is to …
Investigation Of Wear Of Materials By Laser Speckle Photography, Mohamed A. Seif
Investigation Of Wear Of Materials By Laser Speckle Photography, Mohamed A. Seif
Retrospective Theses and Dissertations
This study utilizes a non-contact technique, laser speckle photography, to measure deformations associated with sliding wear. These deformations are those which occur on the "side" of a rectangular-section pin which is in sliding contact against a counterface disc. The "side" of the pin is illuminated by a pulsed ruby laser beam, and a double exposure specklegram is made to obtain deformations which occur between laser pulses. So, by appropriately sequencing pulses, deformation histories can be obtained, in situ. Since the exposed "side" of the thin pin specimen represents the "cover" layer under which subsurface sections lie, the deformation history observable …
The System Design And Evaluation Of A Microprocessor Controlled Dispenser Using A Radar Ground-Speed Sensor, Yu-Charn Chen
The System Design And Evaluation Of A Microprocessor Controlled Dispenser Using A Radar Ground-Speed Sensor, Yu-Charn Chen
Dissertations and Theses @ UNI
This experimental research focused on the design of a new approach to control seed dispensers and to analyze the performance characteristics of a Doppler radar ground speed sensor for a microprocessor control dispenser. The research focused on comparing the effectiveness of using a radar unit with a fifth-wheel encoder for measuring ground speed when both were connected to a microprocessor controlled seed dispenser.
The system designed for this study consisted of hardware and a computer program in 6502 assembly language. The hardware for this study consisted of a monitor device, microprocessor control unit, stepper motor, fifth-wheel encoder, Doppler radar and …
An Experimental Cost Model For The Analysis Of Quality Cost In A Manufacturing Enterprise, Wallace Charles Carlson Jr.
An Experimental Cost Model For The Analysis Of Quality Cost In A Manufacturing Enterprise, Wallace Charles Carlson Jr.
Dissertations and Theses @ UNI
The intent of the study was to construct a quality cost model for manufacturing enterprises. A quality cost model provides a manufacturing enterprise with a cost structure which enables it to gauge and measure the efficiency and effectiveness of its management and processes. The quality cost model was specifically constructed to aid a manufacturing enterprise in establishing a quality cost system for its operations and activities and contains three distinct initial implementation or decision areas; the quality cost management decisions area, the quality cost system applications area, and the quality cost system utilization area.
The quality cost model was evaluated …