Engineering Commons^™

Turbulence Measurements In Stably Stratified Fluids, Yih-Ho Pao

Symposia on Turbulence in Liquids

A towing tank system was used to study the structure of turbulence in stably stratified fluids. Turbulence is generated by moving an obstacle (a grid or a cylinder) in a tank of stratified salt water. Recent improved shadowgraph pictures of these laboratory generated stratified flows are shown in this paper. They give further support to Pao's observation that (i) internal waves and turbulence coexist in turbulent stratified flows, with internal waves at the large scales and turbulence at the small scales; (ii) turbulence decays much more rapidly than internal waves; and (iii) the turbulent-nonturbulent interfaces are not necessarily sharp, and …

The Response Of A Hot-Wire Anemometer To A Bubble Of Air In Water, S. C. Chuang, V. W. Goldschmidt

Symposia on Turbulence in Liquids

The sensitivity of peak voltage drop and duration of the change In sensor voltages due to the impaction of different size bubbles are confuted and measured. Excellent agreement between these is found for bubbles somewhat larger than the sensor diameter and smaller than Its effective length in water streams in a range of 1.5 to 9 feet per second. The method suggests a reliable method for sizing bubbles in a water stream. The effects due to nondirect hits are not treated.

Experimental Investigation Of Polymer Solution Injection On External Boundary Layers, Brian Latto, Chi-Hung Shen

Symposia on Turbulence in Liquids

This paper describes an experimental study of the effects of injecting dilute aqueous polymer solutions into a turbulent boundary layer formed on a flat plate immersed in flowing water.

Hot-film anemometer techniques were employed in the measurement of the velocity profiles, turbulence intensities, and lateral correlation coefficients at a number of locations along the plate. Boundary layer growth parameters and the variation of the local skin friction coefficient were computed from the velocity profile data. The effects of polymer concentration and injection velocity on the local drag reduction are also presented.

It was found that momentum diffusivity was smaller than …

Turbulence Measurements In Dilute Polymer Flows, Joseph M. Wetzel, John A. Almo, John M. Killen

Symposia on Turbulence in Liquids

A hot-film sensor was flush-mounted in the wall of a four-inch pipe and was calibrated as a function of wall shear stress. Flows with water and with homogeneous aqueous solutions of Polyox WSR-301 were utilized. The heat transfer characteristics of the sensor were reduced for polymer flows. Measurements of the number of zeroes and the frequency spectra for the turbulent fluctuations were obtained for a variety of test conditions. The effects of Polyox WSR-301 on surface pressure fluctuations on both smooth and rough surfaces were also measured.

An Experimental Facility For The Visual Study Of Turbulent Flows, Robert S. Brodkey, Harry C. Hershey, Edward R. Corino

Symposia on Turbulence in Liquids

An experimental technique which allows visual observations of the wall area in turbulent pipe flow is described in detail. It requires neither the introduction of any injection or measuring device into the flow nor the presence of a two-phase flow or of a non-Newtonian fluid. The technique involves suspending solid MgO particles of colloidal size in trichloroethylene and photographing their motions near the wall with a high speed movie camera moving with the flow. Trichloroethylene was chosen in order to eliminate the index of refraction problem in a curved wall.

Evaluation of the technique including a discussion of limitations is …

Experimental Investigation Of The Hydrodynamic Stability Of Flow In Rotating Pipes Using Thermistors, Hassan M. Nagib, Ludwig Wolf Jr.

Symposia on Turbulence in Liquids

The hydrodynamic stability of flow in a rotating pipe Is investigated experimentally using thermistors. The experimental apparatus consists of a rotating pipe made of lucite, 3-1/4 inch inside diameter, six feet long, equipped with porous plugs at the ends to minimize recirculation. The working fluid is water and a range of axial and tangential Reynolds numbers up to 7,000 and 20,000, respectively, is covered. Thermistors were chosen for this study since their high electrical resistivity yields strong signals which permit the use of inexpensive and convenient electronics. They also have a high temperature coefficient of electrical resistance which minimizes the …

The Structure Of A Turbulent Water Jet, Philip J. Morris

Symposia on Turbulence in Liquids

Experimental studies are made to determine the structure of a turbulent water jet.

The paper is divided into two parts. The first gives practical information about the techniques and instrumentation developed to make measurements with hot-wire anemometers in water. A short theoretical discussion is given on the dynamic response of heated fibre in liquids. The second part reports on the results obtained in a one-inch water jet at Reynolds numbers between 12,000 and 20,000. Mean axial velocity measurements are made in the initial five diameters of the jet and the results are used to predict the nature of the vortex …

Author Index, University Of Missouri--Rolla

Symposia on Turbulence in Liquids

No abstract provided.

Diffusion Coefficients Over Rough And Smooth Boundaries, Obtained By Measuring The Concentration-Velocity Covariance, R. S. Mcquivey, T. N. Keefer

Symposia on Turbulence in Liquids

A preliminary investigation of the coefficients of turbulent diffusion in an open channel was conducted by employing: 1) hot-film anemometry to detect the velocity fluctuation, 2) a platinized single-electrode conductivity probe to detect the concentration fluctuations, and 3) a digital computing system to evaluate the covariance and other statistical properties of the two output signals.

Data were collected downstream of a constant-discharge point source of neutrally-bouyant salt solution at stream temperature and velocity. Using current semi-empirical methods diffusion coefficients were obtained in the vertical and lateral directions as well as dispersion coefficients due to convection.

Use Of A Constant Temperature Hot-Wire Anemometer To Compensate For The Thermal Lag, Peter Freymuth

Symposia on Turbulence in Liquids

A constant temperature hot-wire anemometer can be used to compensate for the thermal lag of a wire or film resistance thermometer within the useful frequency range of the anemometer. This method may be used as an alternative to the standard method in which a differentiation circuit as employed in constant current anemometers is used for frequency compensation. The new method is useful if a constant temperature anemometer is at hand. The time constant of the resistance thermometer need not be determined.

Frequency Response Studies For A Wedge Probe In Viscoelastic Fluids, J. M. Rodriguez, Gary Kent Patterson, J. L. Zakin

Symposia on Turbulence in Liquids

The response of a hot-film wedge probe in viscoelastic fluids has been investigated by imposing on the probe a sinusoidal vibration of known amplitude and frequency. Root-mean-square (rms) velocities calculated from the displacement of the probe were compared to rms velocities obtained with a constant temperature anemometer. The tests were performed under turbulent flow conditions and also at flow rates where viscoelastic effects (i.e., decrease of heat transfer rates from the probe to the fluid and drag reduction) were observed.

The frequency range covered was narrow ( < 100 cps). This limitation was imposed by the decision to superimpose the sinusoidal vibrations on the turbulence signal, in order to have dynamic conditions similar to those encountered in actual turbulence measurements. Measurements were performed in mineral oil and four solutions of polyisobutylene (Vistanex L-200) In mineral oil.

The experimental technique was established by measuring the response of the probe in …

Some Aspects Of Flow Through Rotating Circular Tubes, D. L. Boyer, J. R. Guala

Symposia on Turbulence in Liquids

The flow of water in a circular tube rotating about an axis perpendicular to the axis of the tube is studied. Information about the flow is obtained from coated hot-film probes and a constant temperature anemometer. A maximum Reynold's number of 9,500 is obtained and the Taylor number is varied from 800 to 3,100. Little similarity is found to exist between flows in rotating and in non-rotating systems in this range of parameters.

Measurements Of Turbulence Characteristics In Water And In Dilute Polymer Solutions, Tadeusz Kowalski

Symposia on Turbulence in Liquids

Measurements of turbulence characteristics were made inside a boundary layer in external flow of water and in water with polymer additives of the Polyox type. Flush mounted hot-film sensors and wedge, parabolic, and cylindrical sensors were used to measure the turbulent velocity fluctuations. Graphs are given of energy density, dissipation, turbulence shear correlation spectra, and microscale of turbulence distribution. Tests were run in an open channel flow at one Reynolds number and two rates of polymer injection to give 20 and 40 ppm average concentration in the boundary layer. The results indicate that the advent of the quartz insulated hot-film …

Industrial Arts Research Methods, Clinton E. Langstraat

Graduate Research Papers

This report has been compiled as one of the culminating activities of 33:292 Industrial Arts Research Methods. This paper can be considered as a written record of the students' and instructor's efforts in establishing further guidelines for work in 33:270, and related activities. Consequently, the report is not highly technical in nature and the number of citations is considerably less than may be found in a typical report written for graduate credit.

However, it is the opinion of the writer that some valuable information has been recorded and it is his hope that some future graduate student may find it …

11th Annual Rocky Mountain Spectroscopy Conference

Rocky Mountain Conference on Magnetic Resonance

Program and abstracts from the 11th annual meeting of the Rocky Mountain Spectroscopy Conference, sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 4-5, 1969.

Engineering Geognosy Of Boyd County, Tommy C. Hopkins, Jerry G. Pigman

Kentucky Transportation Center Research Report

Engineering soils and geologic maps are proving to be invaluable tools of engineers, industrial leaders, community planners, and administrators during tbe preliminary stages of planning and site selection for major construction projects and the development of plans to use nature's basic resource--the land. Quantitative engineering data for soils and geological formations, and the interpretation of tbese data, are important factors to consider in the best land-use plans and in providing stable foundations and proper usage of earth materials for highways, buildings, and other earth structures. Engineering soils and geologic maps can be used to great advantage by planners and engineers …

A Preliminary Evaluation Of Mounds To Divert Wayward Vehicles Away From Rigid Obstructions, Gordon R. Garner, J. B. Venable

Kentucky Transportation Center Research Report

In the summer of 1965, the first fatality report involving an interstate median bridge pier in Kentucky caused concern among state and national officials for the safety of motorists who perchance or otherwise enter upon a collision course toward an unprotected bridge pier. A consensus of opinion seemed to indicate that some form of attenuation or deflection device was necessary.

Early innovations employed various short guardrail configurations to deflect wayward vehicles from the piers. The use of small, short sections has since evolved until present methods include surrounding the bridge pier with several hundred feet of guardrail, including ramped-end treatment …

An Optimization Technique Applied To The Determination Of Orthotropic Material Properties Using Dynamic Response Test Data, Ronald L. Webster

Theses and Dissertations

A knowledge of the behavior of a material under loading similar to expected service loading is required before that material can be used effectively in the design process. Without sufficient mechanical properties data, the design process degenerates to a time consuming and often costly "build, test and modify" type of program. Obviously, this trial and error approach leaves much to be desired.

A Computer Procedure For The Identification Of Beam, Spring, And Damping Parameters Of An N-Mass Model Using Transient Data, Lynn A. Christiansen

Theses and Dissertations

If, however, one could develop a model for a given physical system, that is a model which can be described in terms of lumped masses, springs beams, and dashpots and then identify the parameter simply by processing acceleration data such as that obtained from drop tests or shaker tests, the task of identification is greatly simplified.

Analytical Study Of Heat Conduction And Thermal Stress In Solids With Pressure Dependent Contact Resistance, Dhruvkumar S. Patel

Theses and Dissertations

In the usual thermal stress analysis of a body, the stresses are found for a predetermined temperature distribution. In problems involving composite materials, thermal contact resistance between materials can significantly affect the temperature distribution. The contact resistance is normally a function of the contact pressure and thermally induced stresses can affect the temperature distribution. Thus in composite bodies the thermal stress problem and the heat transfer problem may be coupled and require a simultaneous solution of both problems.

Water Injection In An Automobile Gas Turbine Combustion System, Billy Ray Jackson

Theses and Dissertations

"GENTLEMEN, JUNK YOUR ENGINES!" This title of a recent periodical article [1]* catches some of the expectation for the wedding of the Automobile and the Gas Turbine, The nuptials cannot be completed though, unless two problems are overcome: 1) high fuel consumption, and 2) high operating temperature. The first problem is solvable by the use of heat regeneration and much work has been done in this area [2][3] [4]. The solution of the second problem of high operating temperature was the basis for this thesis. The method of solution was by water injection into the combustion gases prior to entrance …

Optimization Of Physical Properties Of Hydraulic Cushion Cells For Vehicle Impact Restraint, William Evans Hughes

Theses and Dissertations

In recent years, the United States has witnessed a vast expansion of its internal highway system. Concurrently the number of vehicles has increased as has the average yearly milage per vehicle. Unfortunately, along with increased vehicle use there has been an alarming increase in annual loss of life and property due to traffic accidents. Statistics verify that the modem freeway systems greatly reduce dangerous head on collisions but the rate of accidents due to collisions with fixed objects in or near the roadway has increased almost 50 percent in the past thirty years.^1 In 1966, about 13>300 deaths were …

Large Deflection Analysis Of Laterally Restrained Reinforced Concrete Slabs, Satwant Singh Rihal

Civil Engineering ETDs

This dissertation is an attempt to analytically predict the large deflection behavior of orthogonally reinforced concrete slabs. The problem considered is that of a laterally restrained, simply supported square slab under uniform loading. The range of loading considered is from zero load to the load at which yielding first commences in the steel reinforcement.

This problem is first formulated using the classical large deflection theory of homogeneous plates. This formulation is based on a constant overall stiffness for the entire slab.

A modified large deflection theory is next developed for reinforced concrete slabs. In this theory concrete on the tension …

A High Voltage Regenerative Pulse Modulator, James D. Doss

Electrical and Computer Engineering ETDs

This paper describes the design of a High Voltage Pulse Modulator that employs positive feedback to generate output pulses of variable width. The modulator is intended for use as a switching device to drive the modulating anode of a five-cavity klystron. The klystron develops more than one million watts of peak power at a frequency of 805 MHz, with duty factors up to 12%. The modulating anode voltage drive requirement is approximately 80 kV with the current drain being of the order of 0.01 ampere. The total modulator current output will be approximately one ampere with most of the current …

Improved Numerical Techniques And Solution Of A Separated Interaction Of An Oblique Shock Wave And A Laminar Boundary Layer., Ben Douglas Gay

Mechanical Engineering ETDs

Initial, boundary and differencing techniques of numerical gas dynamics were improved, and a separated interaction of an oblique shock wave and a laminar boundary layer was solved numerically.

The computing time of a Lax-Wendroff differencing technique was reduced 60 percent by making algebraic changes. Inflow and wall boundary techniques were improved, and the new techniques were verified by satisfactory solutions of plain laminar boundary layers and unseparated interactions of oblique shock waves and laminar boundary layers. The differencing technique was numerically unstable for separated interactions.

Results of a sample all-centered differencing technique agreed with those of a Lax-Wendroff technique for …

Cold-Rolled Austenitic Stainless Steel: Materials Properties And Structural Performance, George Winter, S. T. Wang

CCFSS Library (1939 - present)

The cold reduction in thickness of austenitic stainless steel sheet brings about the following significant characteristics of material properties: 1) higher strength with an increasing amount of cold working, 2) more pronounced anisotropic material properties with increasing cold working, 3) stress strain relations different in tension and compression and depending on directions, and 4) nonlinear stress strain curves with relatively low elastic limits, especially in longitudinal compression. In addition, local buckling is encountered in thin walled structural members. These are the problems associated with the structural design of stainless steel members. The purpose of this investigation is to develop the …

A Noise Figure Lower Bound And A Frequency Converter, Grant Myers

Department of Electrical and Computer Engineering: Faculty Publications

This article establishes a lower bound for the noise figure of two networks in cascade. This is illustrated by means of a passive low-level frequency converter which utilizes a back diode as a nonlinear conductance. Other investigators have analyzed the properties of low-level frequency converters. However, the greatest lower bound of a combination of the converter and intermediate frequency amplifier system was not considered previously and is the subject of this paper. Knowledge of this lower bound has practical significance because if a measured value of noise figure is less than this lower bound, it follows that the measurement is …

Use Of A Tungsten Filament Lamp As A Pirani Gauge For Continuous Gas Analysis, Donald S. Remer, Fredrick H. Shair

All HMC Faculty Publications and Research

Reported herein is a thermal conductivity technique by which continuous and quantitative data have been obtained in a cataphoretic system without sample withdrawal.

Chemistry Of The Oxidant, Ferrate, Its Interaction With Specific Organics Found In Waste Water, Donald H. Williams, J. T. Riley

KWRRI Research Reports

It became obvious during this investigation that while much work has been done with ferrate (VI) chemistry, discrepancies existed in the literature and very little attention had been given possible engineering uses. This work attempted to fulfill these two needs in an exploratory manner.

The preparative techniques were reviewed and mechanical improvements made in one which allowed improved yields. Essentially what was done was to enlarge and improve the filtering technique of the product and use cooler temperatures throughout the preparation. This greatly shortened the time required. Then it was learned that the addition of ethyl alcohol to the final …

Diffusion Coefficients Of D-Glucose In Aqueous Carboxymethylcellulose And Carboxypolymethylene Solutions, A. L. Huang, S. V. Desai, Robert M. Wellek

Chemical and Biochemical Engineering Faculty Research & Creative Works

A micro interferometric method was used to determine pseudo-binary, molecular diffusion coefficients for diffusion of D-glucose in aqueous carboxymethylcellulose (CMC) and aqueous carboxypolymethylene (Carbopol) solutions. An initial solute concentration of about 9 wt. % D-glucose in the aqueous polymer solutions was used. The polymer concentrations for the CMC solutions ranged from 1.2 to 2.2 wt. % and for the Carbopol solutions from 0.18 to 0.28 wt. %. Diffusion coefficients were determined as a function of reduced solute concentration, both with and without the effect of solution volume change during diffusion being considered. © 1969, American Chemical Society. All rights reserved.