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Statistical Analysis Of Instantaneous Velocities In Turbulent Flow Of Dilute Viscoelastic Solutions, A. L. Rollin, F. A. Seyer

Symposia on Turbulence in Liquids

An experimental study, based on streak photograph determination of instantaneous velocities, was directed at determining the structure of turbulence within the boundary layer and core regions of circular pipes. The measurements lend support to the ejection phenomenon as the mechanism controlling drag reduction.

A correlation factor, defined as the ratio of the observed number of positive instantaneous radial velocities, to the observed number of negative instantaneous radial velocities, suggests acceleration in the radial direction as the elements of fluid move through the sublayer. The correlation factor also provides information about the thickening of the boundary layer for drag reducers relative …

Flow Visualization Studies On Drag-Reducing Turbulent Flows, R. H. J. Sellin

Symposia on Turbulence in Liquids

Flow visualisation studies in a square duct of internal dimensions 44.5 x 44.5 mm are reported. The flow marker is a stream of opaque white dye, released from a downstream facing stationary tube, and it is photographed through the plexiglass wall of the duct. The point of dye release can be traversed in a direction perpendicular to the duct wall and three locations are investigated, two in the core of the flow and one in the near- wall region. By using Is exposure times photographs are obtained of a dye dispersion cone and the cone angle is measured and related …

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 …

Charge Transfer Between Oˉ Ions And O₂ Molecules In The Ground State And Singlet Delta Excited State, Ronald Floyd Mathis

Doctoral Dissertations

"A crossed-beam apparatus has been built and used to study charge transfer between O⁻ ions and O₂ molecules in the ground state and in the metastable, singlet delta, excited state. The energy of the incident ions ranged from 10 to 10,000 eV.

The cross section for charge transfer between O⁻ and ground state O₂ was found to peak at about 5 keV, as predicted on the basis of the Rapp and Francis theory. At the lower energies there is good agreement with the previous measurements of Snow et al., and Rutherford and Turner, who also used crossed beam techniques. The …

Faculty Senate Minutes 1972 - 1973, Missouri University Of Science And Technology Faculty Senate

Minutes & Agendas

No abstract provided.

A Technique For Improving Material Balance Accuracy In Reservoir Simulation Models, A. R. Merchant, Marion D. Arnold, A. Herbert Harvey

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

One criterion for determining the precision of pressures calculated by a simulation model is the accuracy of the material balance. A high degree of precision in the calculated pressures is a necessary but not sufficient condition for elimination of significant errors in the prediction of fluid migration in the reservoir. A new procedure, called error matrix technique, has been developed for reduction of material balance errors. This reduction is accomplished by adjusting potential gradients at every grid point in the simulation model so that the material balance is accurately maintained. Performance of a hypothetical oil reservoir was simulated both by …

Transmission Measurements Through Liquids In A White Cell, David Earl Hurley

Masters Theses

"The suitability of using the White cell for determining the extinction coefficient of liquids was examined by measuring the attenuation of electromagnetic radiation, in the visible part of the spectrum, through distilled water. The analysis of the transmittance measurements through liquids in a White cell does not provide a sufficient number of independent equations to solve directly for the extinction coefficient. Reasonable estimates however can be made by employing a correction which accounts for changes in the mirror reflectance due to a liquid-mirror interface.

The reduction in the transmittance of distilled water due to an oil film was studied for …

A Study Of The Ability Of Surface Active Materials To Increase The Evaporation Rates Of Small, Freely Falling Water Drops, David Alan Sierawski

Masters Theses

"The evaporation rate at 30°C of water droplets partially covered by surface active materials (SAM) were determined. While two of the SAM were studied at a single dew point depression (ΔT_DP), seven others were examined over a range of ΔT_DP values. It was found, by comparison with pure water drops under identical conditions, that SAM increases the evaporation rate as compared to the rate of an uncontaminated drop. The lack of effect of the hydrophobic chain length and the possible effect of the hydrophilic group on this phenomenon are discussed. The explanation proposed is that at 30°C …

A Study Of The Pulse-Height Response Of Silicon Surface-Barrier Detectors To High-Energy Heavy Ions, Gregory Dan Smith

Doctoral Dissertations

"The pulse-height defect (PHD) of high-energy heavy ions in silicon surface-barrier detectors can be divided into three components: (1) energy loss in the gold-surface layer, (2) a nuclear-stopping defect, and (3) a defect due to recombination of electron-hole pairs in the plasma created by the heavy ion. The plasma recombination portion of the PHD was the subject of this study using the variation of the PHD with (1) the angle of incidence of incoming heavy ions, and (2) changes in the detector bias. The Tandem Van de Graaff accelerator at Argonne National Laboratory was used to produce scattered beam ions …

Oxidation Of Tetragonal Pbo In Air, Charles A. Sorrell

Materials Science and Engineering Faculty Research & Creative Works

Isothermal oxidation of tetragonal PbO in air produced multiphase assemblages with apparent equilibrium compositions which varied linearly with temperature from PbO1.548 at 286°C to PbO1.333 at 351°C. Oxidation at each temperature was relatively rapid to PbO1.40 and very slow from PbO1.40 to apparent equilibrium values. Pseudocubic PbO1+x, with compositions between PbO1.41 and PbO1.57, was indexed on a cubic unit cell at the lower O/Pb ratios and on a tetragonal unit cell at the higher ratios. Linear changes in lattice parameters and deviation from cubic symmetry accompanied reversible oxidation and reduction of the phase. Pseudocubic PbO1+x was reduced irreversibly to Pb3O4 …

Stratigraphic Relations Of Members Of The Needles Range Formation At Type Localities In Southwestern Utah, M. G. Best, R. T. Shuey, C. F. Caskey, S. Kerry Grant

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The Needles Range Formation is one of the most extensive of the middle Tertiary ash-flow sheets in the Great Basin of Nevada and western Utah. The original definition of the formation by Mackin (1960) named two members and mentioned three type localities. Our recent studies have shown that this published information now requires revision. To provide a firm basis for stratigraphic studies of the Needles Range Formation, this paper presents geologic maps, measured sections, and paleomagnetic data for three type localities in southwestern Utah. These include the northern Needles Range and Wah Wah Springs localities previously mentioned by Mackin, plus …

Measurement Of Unsteady Flows In Mercury With Hot-Film Anemometers, Charles A. Sleicher, G. B. Lim

Symposia on Turbulence in Liquids

The difficulties in making turbulence measurements in liquid metals are discussed briefly. Attention is then focused on the problem of frequency response attenuation of hot-film anemometers by the thermal capacity of the thermal boundary layer near cylindrical sensors. A solution is given to the problem of heat transfer from an infinite cylinder normal to the potential flow of a fluid with a small sinusoidal velocity component. Application of the results to anemometer measurements is discussed. Some preliminary experiments on dynamic calibration are reported, and they are in reasonable agreement with the theory for Peclet numbers less than one.

Turbulence Measurements In Submerged Water Jets By Electromagnetic Induction Anemometry, Walter C. Mih

Symposia on Turbulence in Liquids

This paper describes the measurement and data analysis of the turbulence in a two-dimensional water jet discharging from a thin slot into a large body of stationary water having the same width as the slot. Tap water without additives was used as the flow medium. The electromagnetic induction method (commonly known as magnetohydrodynamics, or the MHD method) was used to sense the fluctuation velocities in the diffusion zone of the jet. A DC magnet was placed outside the flow field with the magnetic flux density of 885 Gauss perpendicular to the plane of homogeneity of the two-dimensional flow field. A …

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.

Ldv Measurements In Turbulent Free Convection, R. J. Adrian

Symposia on Turbulence in Liquids

The design and performance of a laser Doppler velocimeter (LDV) used in a turbulent water-overice convection experiment are described. The LDV was operated in a reference beam mode with an ultrasonic diffraction grating shifting the reference beam frequency to provide bipolar sensing of the vertical velocity, and a phase-locked loop was used to demodulate the Doppler frequency information. The maximum observed velocities in the experiment were ± 1 mm/sec, and the accuracy of instantaneous measurement was limited by Brownian motion and laser line width to ± .04 mm/sec for a 2 Hz frequency response. The practical difficulties encountered in this …

Features Of A Separating Turbulent Boundary Layer As Revealed By Laser And Hot-Film Anemometry, R. L. Simpson, J. H. Strickland, P. W. Barr

Symposia on Turbulence in Liquids

Experiments have been performed to determine the fundamental nature of boundary layer separation produced by an adverse pressure gradient. Measurements upstream and downstream of the separation zone have been made utilizing laser and hot-film anemometry techniques.

A completely mobile backscattering laser anemometer was developed. This alone is a significant development because of the relatively long focal lengths required for measurements in a 36" wide wind tunnel. Signal processing was achieved by a digital signal sampling and storage system. Both mean and fluctuating velocities in both the unseparated and separated flow regions were measured. Experimental results are in fairly good agreement …

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 …

Design Considerations For A Laser Doppler Velocimeter, Leroy M. Fingerson

Symposia on Turbulence in Liquids

In optimizing an instrument design, it is important to differentiate between the theoretical limitations of the technique and apparent limitations that can be reduced or eliminated by design. In the laser-Doppler anemometer, the theoretical limits are associated with the fact that particle velocity is the measurement rather than fluid velocity. The accuracy and speed of the particle velocity measurements do not appear to have theoretical limitations. Therefore, instrument design must concentrate on improving the measurement of particle velocity.

A complete system has been designed to optimize accuracy, speed, convenience, and flexibility in measuring particle velocity. The problems inherent in transferring …

Optimization Of An Lda System, Robert Smid

Symposia on Turbulence in Liquids

This paper discusses the various considerations leading to the optimization of a laser Doppler anemometer for measurements in the flows of gases, liquids, and solids. The requirements placed on the various parameters of the optics by the experiment are discussed in general for different modes of operation. Expressions determining these optical parameters in certain instances given by various authorities are presented and compared. This includes such topics as: laser power, particle size, measuring volume size, optical variation in transmitting and receiving optics, and photodetector selection.

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.

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. …

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 …

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 …

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 …

Chemical Shift Parameters For Shallow Donors In Semiconductors, Edward Boyd Hale

Physics Faculty Research & Creative Works

A model for a shallow donor impurity in a semiconductor is used to calculate two relationships and several conditions involving the chemical shift parameters. The model is based on the standard effective mass form for the donor electron wave function, the existence of a potential in the chemical cell which may be real, pseudo, or rather general in nature, and a few somewhat restrictive approximations. The parameters, Δ, δ and Λ are theoretically calculated and are shown to be related if the approximations are valid. These parameters determine the 1S multiplet level structure and it is shown how properties of …

Production Of Metastable Ions In Cesium-Atom-Electron Collisions, Kaare J. Nygaard, Yu Bong Hahn

Physics Faculty Research & Creative Works

The structure in the total electron-impact ionization cross section in cesium can be partially accounted for by the mechanisms of autoionization and excitation ionization of 5p electrons. For electron energies above 17 eV a large fraction of the ions are metastable and can de detected by Auger emission from a metal surface. The experiment was performed in a cesium-atom-electron crossed-beam apparatus, and the metastable ions were counted with a channel electron multiplier. The metastable-ion count rate was a factor of 100 higher than that due to photons from atomic and ionic transitions. We have measured the over-all excitation function for …

Molecular Beam Measurements Of Total Collision Cross Sections Of H 22o, William R. Snow, J. T. Dowell, J. G. Chevrenak, H. E. Berek

Physics Faculty Research & Creative Works

The total cross section for H22O-H22O scattering is measured with a supersonic nozzle beam system. The primary beam has a narrow velocity distribution, and the velocity is varied by control of the nozzle temperature. Velocities are determined by time-of-flight techniques. Cross sections obtained are averages over a Maxwellian distribution of the target molecules. Data at three velocities are presented. The cross sections for H2O are surprisingly small, for example, 3.07 x10-14 cm2 at 1x105 cm/sec, indicating little contribution from the dipole-dipole interaction.

Absolute Differential Elastic- And Inelastic-Scattering Cross Sections In 25-140 Kev He+ + He Collisions, Victor Pol, Walter Kauppila, John T. Park

Physics Faculty Research & Creative Works

Data obtained as energy-loss spectra at angles from 0 to 7.3x10-3 rad (c.m.) with typical energy-loss resolution of 0.7 eV and angular resolution of 2x10-3 rad (c.m.) were used to calculate average differential cross sections dσdΩav for elastic scattering, direct excitation of the individual He(n=2) states, and direct excitation of the He+(n=2) states. The total cross section for excitation of the He(n=2) states obtained by integrating the differential cross sections was found to be 20x10-18 cm2 at 25 keV (lab) decreasing to 7x10-18 cm2 at 140 keV. At incident lab energies below 100 keV the He(2S2) and He(2P3) states dominate …

Penning Ionization Of Zn And Cd By Noble-Gas Metastable Atoms, L. A. Riseberg, William F. Parks, Laird D. Schearer

Physics Faculty Research & Creative Works

The Penning-ionization cross sections for He, Ne, Ar, and Kr metastable atoms with Zn and Cd have been measured in a pulsed afterglow. Within the framework of existing theories we have determined those parameters which are of importance in collisions of this type. We find that our data are internally consistent if the cross sections are proportional to the cube of the "hard-sphere" radii and the effects of selection rules are included. A theoretical basis for this dependence is suggested. © 1973 The American Physical Society.