Digital Commons Network^™

Analysis Of Spread Multi-Jet Vtol Aircraft In Hover, Leroy F. Albang

Mechanical & Aerospace Engineering Theses & Dissertations

An investigation of VTOL aircraft lift losses in hover has been conducted to evaluate a method for a simplified test technique. Three flat plate models were tested to determine their usefulness in predicting hover characteristics by comparing results between plate and three­ dimensional models. Attempts to correlate the out of ground effect results for the plate models with the empirical expression for calculating jet-induced loads were successful for the models which used engine simulators producing efflux characteristics similar to the three­ dimensional model engines. Data for the model using engine simulators with characteristics unlike those of the three-dimensional model simulators …

A Method For Improving The Accuracy In Phase Change Heat Transfer Data Through Increased Precision In Thermophysical Property Determinations, John Philip Drummond

Mechanical & Aerospace Engineering Theses & Dissertations

Wind tunnel model materials typically have thermophysical properties that vary with both position and temperature. A numerical study using a finite difference representation of the heat conduction equation has been performed on several of these model materials to determine their thermal response under a specified heat loading. This study has confirmed the feasibility of using an effective thermophysical property to account for the existence of variable thermal properties when a model undergoes aero­ dynamic heating. The effective property, when used in the reduction of phase-change heat transfer data, forced agreement of the actual transient behavior of a model with the …

Effect Of Rod Gap Spacing On A Suction Panel For Laminar Flow And Noise Control In Supersonic Wind Tunnels, William D. Harvey

Mechanical & Aerospace Engineering Theses & Dissertations

It has been well established that the test section flow of conventional supersonic and hypersonic wind tunnels contains significant levels of disturbances. These disturbances are mainly caused by the radiation of aerodynamic noise from the turbulent boundary layer on the nozzle walls. This noise level has been shown to have an important effect on boundary layer transition measured on models in tunnels. The purpose of this thesis is to present results of a coordinated experimental and theoretical study of a sound shield concept which aims to provide a means of noise reduction in .the test section of supersonic wind tunnels …

A Study To Determine The Feasibility Of Implementing The Senior Intensified Retail Selling Program In The Four Senior High Schools In Hampton. Virginia, Virginia Cooke Johnson

OTS Master's Level Projects & Papers

The following researching questions guided this study: 1. Do a sufficient number of those students identified as lacking job entry skills have an interest in taking the senior intensified retail selling program to warrant its establishment? 2. In the community where these students will seek work, are the local retail selling job opportunities sufficient for the enrollment? 3. Are facilities and equipment necessary to teach this course available in the local high schools? 4. Is there enough time available in the teaching schedules of the Distributive Education coordinators to allow the addition of the new senior intensified retail selling program?

The United States Naval Influence In South Russia, 1917-1922, Beverly A. Lowe

History Theses & Dissertations

Abstract unavailable.

American Policy And The Netherlands East Indies, 1940-1945, Buford A. Harris

History Theses & Dissertations

Abstract unavailable.

The Effect Of Unreinforced Cutouts On The Buckling Of Thin Conical Shells Loaded By Central Axial Compression, Garla Arjuna

Mechanical & Aerospace Engineering Theses & Dissertations

Analytical trends for the linear bifurcation buckling of thin isotropic right-circular-conical shells with unreinforced cutouts are investigated. Clamped, constant-thickness conical shells with homogeneous, isotropical material properties are analyzed for uniform axial compression. The buck­ ling loads are obtained by the use of the STAGS (Structural Analysis of General Shells) computer program which is based on a finite difference numerical approach. Variables defining the geometry of the cutout and the cone are nondimensionalized and the relationship between the nondimensional buckling load and nondimensional cutout parameter is established. A range of the cutout sizes is investigated for which linear bifurcation buckling results …

Application Of Boundary Layer Theory To Suction Through Streamwise Slots In Wind Tunnel Walls, Michael Harold Berger

Mechanical & Aerospace Engineering Theses & Dissertations

A theoretical investigation at Mach 6 and 8 has been conducted on a model of a wind tunnel sound shield. The flat plate model consists of interchangeable circular and wedge shaped longitudinal rods with gaps between the rods for boundary layer removal. One­ dimensional gas dynamics results have been applied to model the pressure distribution for the array of cylinders. Comparisons with experimental pressure distributions and numerical potential flow solutions indicate good agreement. It has been demonstrated that stagnation line heat transfer can be accurately predicted for laminar and-turbulent flow for circular cylinders. The flow around the wedge rods was …

Dynamics Of Explosion Remnants In Earth-Orbits, Joseph T. Fuss

Mechanical & Aerospace Engineering Theses & Dissertations

Explosions in space produce particles that are hazardous to space vehicles. Some of these particles are not trackable and their locations must be predicted by dynamical methods.

This investigation sheds light on three different, areas, First, ignoring perturbations, the characteristics of a three dimensional envelope outlined by the sum of individual particle orbits is determined, Second, the distribution of the particles is found as a function of time, Finally, the movement, of the body via secular perturbations is investigated. Magnitudes of the explosion, the point of. detonation in the parent satellite's orbit, and the radius of perigee of the parent …

An Experimental And Theoretical Study Of The Flow Phenomena Within A Vortex Sink Rate Sensor, Dashrath Khodidas Patel

Mechanical & Aerospace Engineering Theses & Dissertations

The objective of this investigation was to obtain a detailed description of the flow field within a vortex sink rate sensor and to observe the influence of viscous effects on its performance.

The sensor basically consists of a vortex chamber and a sink tube. The vortex chamber consists of two circular coaxial disks held apart, at their periphery, by a porous coupling. One circular disk has an opening to permit the mounting of the sink tube, in such a manner that the vortex chamber as well as the sink tube have a common axis of rotation.

Air was supplied radially …

A Comparison Of Selected Isokinetic Training Velocities On The Development Of Muscular Power In College Women, Julia P. Knight

Human Movement Studies & Special Education Theses & Dissertations

The purpose of this study was to compare the effects of three different isokinetic velocities on the development of muscular power. Seventy-five college females were matched into four equal groups according to the average of their pre-test scores on the Vertical Power Jump Test and the Power Staircase Test. Group I served as the control group, while all 3 of the experimental groups performed the same isokinetic exercise at different pre-set rates of speed. Groups II, III and IV worked at the selected rates of .8, 2.3 and 3.9 inches per second respectively. All four groups were pre-tested and post-tested …

The Use Of Color Infrared Aerial Photography In Determining Salt Marsh Vegetation And Delimiting Man-Made Structures Of Lynnhaven Bay, Virginia, Robert E. Holman Lll

Biological Sciences Theses & Dissertations

Color infrared aerial photography was found to be superior to color aerial photography in an ecological study of Lynnhaven Bay, Virginia. The research was divided into three phases: 1) determination of the feasibility of correlating color infrared aerial photography with wetland species composition and zonation patterns, 2) determination of the accuracy of the aerial interpretation and problems related to the aerial method used, and 3) comparison of developed with undeveloped areas along Lynnhaven Bay's shoreline.

Wetland species composition and zonation patterns of major cones were correlated with aerial infrared photography and resulted in a high degree of accuracy. Problems with …

An Ecological Study Of The Craney Island Disposal Area In Hampton Roads, Virginia, David Wallace Laist

Biological Sciences Theses & Dissertations

A one year ecological study was conducted on the Craney Island Disposal Area in Hampton Roads, Virginia. This study attempted to identify the flora and fauna inhabiting the spoil deposits and trace the development of communities from the time of deposition through the initial stages of succession.

One hundred and ninety-two species were identified including 48 vascular plants, 66 insects, 48 birds, 18 species of algae, 4 crustaceans, and 8 vertebrates. The study area was divided into six zones based on substrate characteristics and species composition. The successional patterns and biotic interactions within each zone were discussed.

An Investigation Of Littoral Transport Between Virginia Beach And Sandbridge, Virginia, Richard C. Cunningham Jr.

OES Theses and Dissertations

A method for calculating littoral transport, direct determination of the sediment flux, has been proposed and evaluated. Three sampling stations, located between Virginia Beach and Sandbridge, Virginia, were occupied for a period of thirteen months (September, 1972 to September, 1973). Measurements include velocity of the littoral current, cross-sectional area of the surf zone, and in situ samples of suspended and bottom sediment load. Observations of sea and atmospheric conditions were obtained. Two ways of calculating littoral transport were derived from the same basic method, thus two sets of transport values were generated. Two annual littoral transport values were calculated by …

The Design And Performance Of A Fiber Optic Pressure Transducer, Raymond Henry Pahler Jr.

Mechanical & Aerospace Engineering Theses & Dissertations

Design and performance characteristics of a fiber optic pressure transducer are presented and discussed. The transducer consists of a cylindrical metal housing with a specular reflecting aluminum diaphragm at the distal end and a circular array of fiber optic light guides at the proximal end. The center bundle is connected to a light source with the surrounding bundles carrying reflected light to a photodetector. A change in pressure on the diaphragm causes a deflection which in turn causes a change in intensity over the light receiving fibers. The intensity is converted to a voltage signal by the photodetector circuit. Thus, …

A Finite Element Analysis Of Unsymmetrically Laminated Rectangular Plates, Stanley F. C. Tseng

Mechanical & Aerospace Engineering Theses & Dissertations

The behavior of laminated plates with coupled extension-bending was investigated using the finite element method. A stiffness matrix for a rectangular element with 20 degrees of freedom was developed using a symbolic mathematics interpreter program. A finite element analysis program was written for the analysis of flat plate. Results i for plate deformations and internal moment distributions are compared with existing exact solutions or experimental data and excellent agreement is obtained.

Seasonal Composition Of Zooplankton In The Lafayette River, Norfolk, Virginia, Dahn E. Crandall

Biological Sciences Theses & Dissertations

Abstract unavailable.

Electroplating, James G. Farrell

OTS Master's Level Projects & Papers

Electrometallurgical industries comprise an important segment of the world's manufacture of metal products. These industries involve three major categories: electrowinnowing, electrorefining and electroplating. Electrowinnowing consists of purifying raw ore to a relatively pure metal by electrolysis. Extraction of aluminum from bauxite is an example. Electrorefining involves electrolysis of metallic solutions to recover or produce extremely pure metal. Recovery of precious metals is often done by electrorefining. Electroplating involves the coating of one metal or object with another metal for various reasons. The chief reasons are the protection of a part from corrosion or its beautification. Another type of electroplating is …

The Economic Aspects Of Water Pollution By Naval Vessels In The Port Of Charleston, South Carolina, John Edward O'Connor

Economics Theses & Dissertations

No abstract provided.

Evolution Of Platt Shoals Northern North Carolina Shelf: Inferences From Areal Geology, Philip C. Sears

OES Theses and Dissertations

The evolution of Platt Shoals, a complex ridge and trough system on the south side of the Albemarle Shelf Valley, was determined and the modern hydraulic regime was inferred. The methods used were surficial grain size, 11 vibracores, seismic profiling and bathymetric maps. Platt Shoals developed in a three step process. The first, step was the formation of a substrate of late Pleistocene regressive deposits from 15,000 to 30,000 yr B. P. The second step, occurring approximately 11,000 yr B. P., was the formation of estuary mouth shoals of the ancestral Albemarle River. Between 4,4.00 to 5,000 yr B. P., …

An Investigation Of A Free Jet At Low Reynolds Numbers, George C. Greene

Mechanical & Aerospace Engineering Theses & Dissertations

This thesis presents a comparison of the measured and calculated flow field properties of a nozzle of unusual design which was used to produce an incompressible, low Reynolds number ]et. The "nozzle" is essentially a porous metal plate which covers the end. of a pipe. Results are presented for nozzle Reynolds numbers from 50 to 1000 with velocities of 100 or 200 ft/sec. The nozzle produces s, uniform velocity profile at nozzle Reynolds numbers well below those at, which conventional contoured nozzles are completely filled with the boundary layer. A Jet mixing analysis based on the boundary layer equations accurately …

Phytoplankton Succession In The Lafayette River, Estuary, Norfolk, Virginia, Thomas W. Purcell Lll

Biological Sciences Theses & Dissertations

Abstract unavailable.

A Comparative Limnological Survey Of Brackish-Water Lake And A Fresh-Water Lake At Mount Trashmore, Virginia Beach, Virginia, Gene Ramon Cocke

Biological Sciences Theses & Dissertations

No abstract.

Computer-Aided Design Of Light Aircraft To Meet Certain Aerodynamic And Structural Requirements, Joanne Lynn Walsh

Mechanical & Aerospace Engineering Theses & Dissertations

Nonlinear mathematical programming techniques are applied to a particular aircraft design problem, that of determining the maximum range design for light aircraft subject to certain aerodynamic and structural requirements. Search techniques available in an existing nonlinear optimization computer program, AESOP, are applied to the design problem. Seven design variables are used to define the wing dimensions, the wing skin thickness, the cruise velocity, the amount of fuel carried, and the engine horsepower. The influence of different design requirements on the range is observed and discussed.

Visual Imagery In The Shorter Fiction Of D. H. Lawrence, Archie Leland Simmons

English Theses & Dissertations

No abstract.

Numerical Study Of The Turbulent Boundary Layer In A Hypersonic Nozzle, Joan Patricia Gosink

Mechanical & Aerospace Engineering Theses & Dissertations

A numerical study of the turbulent boundary layer in a hypersonic nozzle is presented. The boundary layer equations are solved by a second order, implicit finite difference scheme developed at Langley Research Center. The technique is applicable to laminar, transitional or turbulent compressible or incompressible boundary layer flows for planar or axisymmetric geometries. A technique is presented for utilizing experimental data to start the finite difference solution.

Turbulent boundary-layer measurements on axisymmetric nozzle walls at Mach number 6 are presented and compared with numerical predictions obtained by starting the solution in the stagnation chamber and from a downstream experimental station. …

Investigation Of The Halocline Structure In Lower Chesapeake Bay, Samuel Bowen Heltzel

OES Theses and Dissertations

A portion of the Chesapeake Bay from 37°20’N latitude to the entrance was investigated to determine the halocline structure, the effects on this structure through the tidal sequence, and seasonal variations. A determination of the stage of slack water during which maximum extension of the halocline occurred was also made. This was accomplished by looking at the salinity distribution at the halocline upper limit, the mean depth to the halocline, and seasonal salinity contours drawn for tidal increments. By comparing salinity/depth gradients and salinity-depth vertical profiles, an attempt was made to relate seasonal and tidal variations to the halocline structure. …

Railroads And Urban Rivalries In Antebellum Eastern Virginia, Peter C. Stewart

History Faculty Publications

Railroad construction provided a focus for the acceleration of economic rivalry between Richmond, Petersburg, and Norfolk from the 1830's through the 1850's. Richmond's place as a political center provided legislative leverage and attracted able promoters and sufficient capital. Richmond outdistanced its rivals handily, with Petersburg gaining little more than Norfolk. The rivalry left an enduring legacy. Based on railroad archives, manuscripts, and newspapers; 60 notes.

Commentary On And Extension Of Calculative Procedure For Co2 Production, Ralph M. Rotty

Mechanical & Aerospace Engineering Faculty Publications

Further refinements are made in the method of calculating amounts of carbon dioxide released to the atmosphere through the combustion of fossil fuels. Data available in the UN Statistical Yearbook are used as the basic sources rather than the summary, World Energy Supplies, U.N. Statistical Papers, Series J because the most recent data are available several months earlier in the yearbook and because data are included for natural gasoline, natural gas liquids, and cement production. Coal, lignite, crude petroleum, “marketed” natural gas, flared natural gas, and cement are itemized separately and revised CO₂ emission estimates are made for …

Seismic Refraction Study Of Post-Pliocene Stratigraphy, Dismal Swamp, Virginia, William Brian Fraser

OES Theses and Dissertations

This study examines Pliocene-Pleistocene lithostratigraphy and the Yorktown unconformity within the Dismal Swamp by means of remote sensing analysis, Wyrobek-Gardner seismic refraction profiling and split-spoon coring. Pre-Sangamon fluvial/tidal channel deposits are not present and the Yorktown unconformity dips irregularly southeastward at 0.35 meters/kilometer (2 feet/mile) from a high at 4 meters above sea level to a low of -1 meter (+12 to -2 ft) below sea level. The marker velocity for the Yorktown Formation is 1600 mps (5250 fps) and regression of seismic depths of the Yorktown Formation with corresponding split-spoon depths yields a high correlation. Short line upper layer …