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Turbulence Measurements With A Sampling Laser-Doppler Velocimeter, P. D. Iten

Symposia on Turbulence in Liquids

A novel sampling signal processor overcomes the difficulties encountered with frequency trackers in the investigation of unseeded highly turbulent flows. This sampling system consists essentially of a swept filter, e.g. a standard RF-spectrum analyzer, a digital data memory and a storage oscilloscope. It is able to determine first-order statistical averages of turbulent flows with high fluctuation frequencies and amplitudes even at very low scattering particle concentrations. Since the velocity samples are not statistically independent of the velocity, the sampled velocity data has to be corrected in order to obtain unbiased statistical averages. A theoretical analysis and experimental investigations of the …

Phase Separation In Turbulent Two-Phase Flow, Francois J. Resch, Hans J. Leutheusser

Symposia on Turbulence in Liquids

The paper is based on an experimental study of a typical instance of bubbly two-phase flow, viz. the air-entraining roller zone of hydraulic jumps in open channels. The investigation was undertaken with the aid of hot-film anemometry techniques involving instant digitization of analog signals, and delayed electronic processing of the tape-recorded data. Special computer programs were designed to separate the two phases according to a well-defined signal threshold. It is this aspect of the work which is being dealt with in the paper.

Turbulent Characteristics Of Two-Phase, Gas-Liquid Stratified Channel Flow, D. M. Johns, T. G. Theofanous, R. N. Houze

Symposia on Turbulence in Liquids

The turbulence characteristics of the bulk phases were studied in a stratified, two-dimensional, gas- liquid channel flow. Initial results are presented comparing mean velocity and turbulent intensity profiles with those obtained in a prior study at the same bulk phase Reynolds numbers. The results indicate that comparison of two realizations of stratified gas- liquid flow cannot be adequately done on the basis of bulk-phase Reynolds numbers. Comparisons must be based on some more fundamental relationships involving the gas-liquid interactions.

Conditioned Sampling Techniques, R. E. Kaplan

Symposia on Turbulence in Liquids

The concept of organized, spatially coherent large scale structures has been investigated for a variety of turbulent shear flows by a technique called "Conditional Sampling." It can be shown that these structures are related to physically important activities such as, 1) the entrainment of turbulent boundary layers, and 2) the maintenance of turbulence by a wall, 3) the growth of free shear layers, and 4) the structure and noise production of turbulent jets.

The general technique of conditioned sampling is related to visualizations of the flow, and to problems of synchronization of images in the presence of noise. While there …

Experiments On The Structure Of Turbulence In Fully Developed Pipe Flow, T. R. Heidrick, S. Banerjee, R. S. Azad

Symposia on Turbulence in Liquids

This paper describes a series of two-point measurements in fully developed pipe flow. Measurements of the phase shifts between the Fourier components of the axial velocity fluctuations at two points were made with three different orientations of the two points. In all cases the two points were close enough together that the turbulent structure remained essentially "frozen" while passing between the sensors. The phase velocities, C₁(f), and inclinations, α(f) (defined previously by Heidrick et al. (8)), of each frequency component, f, were determined from these measurements.

In general, the Fourier components are inclined to the wall - the …

Experimental Measurement Of Particle Dispersion In Turbulent Flow, N. M. Howard, C. C. Meek, B. G. Jones

Symposia on Turbulence in Liquids

The dispersion of particles in turbulent flows, phenomena such as dispersion, diffusion, and sedimentation, and a more fundamental point of view, the description of particle interaction with the turbulent field are recently of increasing interest. A system capable of investigating statistical structure of the motion of particles in a turbulent fluid flow using a turbulent water pipe flow system and particles tagged with C0-60 radioactive pellets has been constructed and tested. The particles were followed in their trajectory by a group of detectors consisting of NaI(Tℓ) crystals mounted on photomultiplier tubes which move with the particles on a movable carriage. …

A Comparison And Analysis Of Detection Methods For The Measurement Of Production In A Boundary Layer, G. R. Offen, S. J. Kline

Symposia on Turbulence in Liquids

Two hot films and dye visualizations have been employed, simultaneously, in a turbulent boundary layer to explore the relations among visual observations and five kinds of detection methods using conditional sampling. The results show that all methods correlate positively with each other, but not with high enough values of correlation coefficients to indicate true correspondence between any two thus far studied. Moreover, none of the detection methods devised to date indicate a plateau in number of events as a function of trigger threshold.

The results also provide additional information on several other matters: (i) the relationship of outward motions from …

An Experimental And Theoretical Study Of The Viscous Sublayer For Turbulent Tube Flow, Lindon C. Thomas, H. L. Greene

Symposia on Turbulence in Liquids

Flush-mounted anemometer probes have been used to further study characteristics of the viscous sublayer for both Newtonian and drag reducing solutions, with particular emphasis given to low Reynolds number turbulent tube flow. Experimental measurements for the mean frequency of bursting or renewal within the wall region are compared with theoretical predictions obtained on the basis of the surface renewal and penetration model.

Both theory and experiment taken together suggest that the effect of the mean axial pressure gradient on the viscous sublayer becomes important for the deeper molecular penetration associated with low Reynolds number flow. Also, a pronounced lessening of …

On The Interpretation Of The Output Of Hot-Film Anemometers And A Scheme Of Dynamic Compensation For Water Temperature Variation, J. Tan-Atichat, H. M. Nagib, J. W. Pluister

Symposia on Turbulence in Liquids

Using a special calibration tunnel developed during the course of this study, the static and dynamic response of several kinds of commercially available hot-film probes with single and multiple sensors of the cylindrical-fiber type are examined. The effects of different parameters, including those of the anemometer bridge, on the output and performance of the probes are evaluated. In particular, the consequences of variations in water temperature on the hot-film anemometer output are determined. The results reveal a large effect of the water temperature on the calibration curves (in an extreme case a change in temperature of only 5.5°F can result …

Use Of The Split-Film Sensor To Measure Turbulence In Water Near A Wall, Paul H. Blinco, V. A. Sandborn

Symposia on Turbulence in Liquids

Because of its small size and unique design, the 0.15-mm diameter split-film sensor has many significant advantages over the conventional X-configuration hot-film sensor and the yaw-wire technique for measuring turbulence near a wall. Calibration of the split- film sensor indicates that the magnitude and yaw angle of the instantaneous velocity vector is dependent only on the sum and ratio of the sensor outputs, respectively. Results of limited measurements of the longitudinal and vertical turbulence intensities and Reynolds stress for hydraulically smooth, free surface flows are presented. Digital time series of the split-film outputs revealed the following information: (1) the split-film …

Author Index, University Of Missouri--Rolla

Symposia on Turbulence in Liquids

No abstract provided.

Measurements Of Pulsating Turbulent Water Flow In A Tube, S.-Z. Lu, R. J. Nunge, F. F. Erian, M. Mohajery

Symposia on Turbulence in Liquids

The experimental method associated with obtaining meaningful information from the hot-film anemometer signals in fully developed pulsating turbulent flow where the pulsations are sinusoidal in time is discussed. The results of a number of experiments in water reveal the nature of the longtime and short-time average velocity and pressure. Velocity measurements between 0.95 radii and the centerline demonstrate that the long-time average velocity distribution is coincident with that for steady turbulent flow at the same Reynolds number. Also, no significant differences between the longtime average axial pressure drop in the pulsating and steady flows were noted, although this requires further …

Intermittency And Structure Of A Jet Exhausting Into A Stratified Fluid, Alan Brandt, H. E. Gilreath, C. L. Yates, C. R. Walton

Symposia on Turbulence in Liquids

This preliminary study of the mechanism by which local turbulent regions generate internal gravity waves in a stably stratified fluid is based on comparisons of the visual and hot-film- anemometer observations of a jet exhausting into a stratified fluid with those for a jet exhausting into a homogeneous medium. The stratified environment limits the growth of the mean jet boundary, or from another point of view, inhibits the vertical motion of the instantaneous turbulent/non-turbulent interface. The visual and non-conditional statistical averages agree with expectations and with previous measurements in stratified turbulent wakes. Application of a standard criterion to determine the …

Promising Directions For Liquid Turbulence Research --Panel Discussion, Victor Goldschmidt, J. H. Whitelaw, V. A. Sandborn, Val Kibens, R. E. Kaplan

Symposia on Turbulence in Liquids

No abstract provided.

Bridge / Tunnel Crossing Study : Portland Harbor - Fore River, Portland - South Portland, Maine Department Of Transportation

Maine Collection

Bridge / Tunnel Crossing Study : Portland Harbor - Fore River, Portland - South Portland

Report by Fay, Spofford & Thorndike, Inc., Engineers, Boston, Mass.

Prepared for the Maine Department of Transportation, Augusta, Maine, 1973.

Contents: Table of Contents / List of Figures / List of Tables / Introduction / Summary of Findings / Section 1 - General Background - Location Study / Section 2 - Alternative Facilities and Locations / Section 3 - Comparison of Construction Costs - Tunnel Versus Bridge / Section 4 - Traffic Analysis / Section 5 - Cost Effectiveness Analysis / Section 6 - Financial …

Tests On Field Welded Puddle And Fillet Weld Connections, R. S. Yarnell, Teoman Peköz

CCFSS Library (1939 - present)

INTRODUCTION This report contains the results of tests on 122 field welded connections. Most of the specimens are approximately the same as those that were shop welded previously and tested. The results of tests on shop welded specimens are given in Ref. 2. Those field welded specimens that do not correspond to the shop welded specimens are indicated in Table lA. Except as noted, all notations, variables, weld configurations and procedures are identical with those in Ref. 2. All specimens were tested in a hydraulic test machine under monotonically increasing slowly applied tensile force. This report differs from Ref. 2 …

Diaphragm Braced Thin-Walled Open Sections And Design Of Wall Studs, Amir Simaan, Teoman Peköz

CCFSS Library (1939 - present)

INTRODUCTION Cold-formed steel wall studs generally are I, Z or channel shaped with or without stiffening lips, and with webs perpendicular to the plane of the wall. Because of their configuration and dimensions, these sections are quite unstable by themselves. However, the stability and, hence, load-carrying capacity of such studs are increased substantially once they are connected to the wallboard material. The main function of the wallboard is that of enclosure, but it serves also as a bracing system for the studs. Gypsum board, vegetable fiberboard, tempered board or plywood are commonly used wallboard materials. Such boards are connected to …

Column Research Council: Proceedings 1973, Column Research Council

CCFSS Library (1939 - present)

One of the purposes of the Council is to maintain a forum where problems related to the design and behavior of columns and other compression elements in metal structures can be presented for evaluation and discussion. The Annual Technical Session provides opportunity to carry out this function. The 1973 Annual Technical Session was held on May 2 and 3 at the Los Angeles Hilton Hotel in Los Angeles, California. Sixty persons attended the Session and thirty-three papers were delivered. A panel discussion on "Frame Stability Under Seismic Loading" was held in the evening of May 2, 1973. Panelists were E. …

Conference Proceedings Of The 3rd Biennial Symposium On Turbulence In Liquids, University Of Missouri--Rolla

Symposia on Turbulence in Liquids

The Third Biennial Symposium on Turbulence in Liquids showed further progress in the investigator's ability to measure turbulence parameters and in the general understanding of turbulence. The most impressive advances in measurement seemed to be the ability to measure deeper into the turbulent boundary layer in order to obtain profiles over the entire turbulence production region and the rapid development of conditioned-sampling techniques for studying hypotheses for mechanisms.

Dynamic Response Of Forced Convective Heat Transfer From Cylinders To Low Prandtl Number Fluids, D. G. Malcolm, V. Verma

Symposia on Turbulence in Liquids

The present paper can be viewed as an extension of the work of Lim and Sleicher (9). They evaluated the frequency response of the heated element submerged in liquid metal by a perturbation method for Peclet numbers of up to 0.4. Velocity fluctuations were assumed small and second-order perturbations neglected. The Oseen approximation was made to the velocity field. Here the velocity configuration has been approximated to that of potential flow and the convection equation has been solved numerically with the aid of a digital computer. The potential flow approximation, as compared with the Oseen approximation, is reasonable over a …

De Los Sealabs A Los Skylabs, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

¿Respiraremos Algún Día El Agua Del Mar?, Javier Gimeno, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

Chronic Toxicity Of A Copper, Cadmium And Zinc Mixture To The Fathead Minnow (Pimephales Promelas Rafinesque), John G. Eaton

United States Environmental Protection Agency: Publications

Fathead minnows were exposed to a series or concentrations of a copper, cadmium and zinc mixture during a 12.5 month chronic test in water of 200 mg 1^-1 total hardness. The metal concentrations in the mixture were selected on the basis of results obtained during previous chronic exposures to each of the metals individually in the same water. Strict summation of the chronic toxicities of the metals was not indicated when they were tested in combination. Toxic effects of the mixture attributable to copper appeared to be increased, but that attributable to cadmium was reduced. The effects thought to …

A Simplified Flow-Splitting Chamber And Siphon For Proportional Diluters, Duane Benoit, Frank A. Puglisi

United States Environmental Protection Agency: Publications

Simplified flow-splitting chambers and siphons were designed and tested for use with proportional diluters in bioassay systems. The apparatus allows each concentration from the diluter to be thoroughly mixed and divided four ways for delivery to duplicate fry and adult exposure tanks. Test water delivered to each exposure tank varied by only 5-10 per cent of the calculated volumes.

Chronology Of Army Medical Intelligence, 1941-1973, Robert Bolin , Depositor, Jonathan Clemente

United States Department of Defense Military Intelligence

This “Chronology of Medical Intelligence” lists the chiefs of the Army medical intelligence effort and the designations of the medical intelligence organization.

Interestingly, the first heads of the effort Captain Tom F. Whayne, MC, USA, and LTC Gaylord W. Anderson, MC, AUS, participated in the preparation of the official history of Medical Intelligence during World War II. SEE: Gaylord Anderson, MD, "Medical Intelligence" IN: Preventive Medicine in World War II. Vol IV, Special Fields, ed. COL Robert S. Anderson, MC, USA and Ebbe Curtis Hoff, PhD, MD (Washington DC, Department of the Army, 1969).

Dr. Arthur Turner, a civilian, was …

Inertial Navigation Performance Improvement Realized By The Technique Of Interrupted Alignment, Ralph E. Herndon

Masters Theses

"Present on-aircraft ground alignment gyro bias methods can basically be categorized as (1) periodic maintenance performed by the ground crew, (2) pre-flight calibration requiring a two-position gyro compass alignment or (3) optimal filter estimation of the north gyro bias error.

This thesis discussion presents an interrupted alignment method that allows adequate level axes gyro bias correction without the restrictions associated with a conventional two-position gyrocompass alignment (i.e., a minimum time for bias calibration on a steady aircraft). The interrupted alignment technique allows the pilot to select the navigate mode at any point during gyrocompass and reselect the align mode at …

A Thin Film Evaporator Rate Controller, Daniel Robert Kasterlein

Masters Theses

"A circuit is described which is used to control the evaporation rate of material from a resistance heated boat or electron beam evaporator. The rate controller is used in conjunction with a quartz crystal thickness monitor in a vacuum evaporator"--Abstract, page ii.

A Nuclear Power Plant Simulator, John Jacob Adams

Retrospective Theses and Dissertations

The United States' energy crisis, which has received so much publicity lately, has focused national attention on how we are to meet our energy demands. Proposed energy sources include conventional nuclear power plants, breeder reactor and fusion reactor plants, coal gasification, liquid hydrogen, solar energy, and geothermal energy. All of these except conventional fission plants are still on the drawing board or in the experimental laboratory, and are described briefly. Government and industry are betting heavily on conventional nuclear power plants. ($40 billion already spent by private utilities for 30 operating plants, 60 under construction, and 75 on order.) A …

The State-Space Approach To Network Synthesis, Gary Landis Hasty

Retrospective Theses and Dissertations

No abstract provided.

The Design Of A Digital Data Acquisition System For Jet Engine Testing, Robert Wesley Carter

Retrospective Theses and Dissertations

This research report documents the various types of Data Acquisition Systems in use for testing jet aircraft engines. The cost trade offs and design considerations are explored for systems which employ a digital computer as the prime recording/processing element. The digital computer has revolutionized the data acquisition field, particularly in the testing of high performance jet engines. Test data can be acquired, processed, converted to engineering units, and out via high speed line printers and cathode ray tubes (CRT's). The data acquisition system operates on-line, and interleaves the random requests for data from multiple test cells by using a specially …