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in subjects: "Viscous"

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Densification and residual stress induced by CO2 laser-based mitigation of SiO2 surfaces

Knowing the ultimate surface morphology resulting from CO{sub 2} laser mitigation of induced laser damage is important both for determining adequate treatment protocols, and for preventing deleterious intensification upon subsequent illumination of downstream optics. Physical effects such as evaporation, viscous flow and densification can strongly affect the final morphology of the treated site. Evaporation is a strong function of temperature and will play a leading role in determining pit shap… more

Date: October 21, 2010

Creator: Feit, M D; Matthews, M J; Soules, T F & Stolken, J S

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Parallel Simulation of Three-Dimensional Free-Surface Fluid Flow Problems

We describe parallel simulations of viscous, incompressible, free surface, Newtonian fluid flow problems that include dynamic contact lines. The Galerlin finite element method was used to discretize the fully-coupled governing conservation equations and a ''pseudo-solid'' mesh mapping approach was used to determine the shape of the free surface. In this approach, the finite element mesh is allowed to deform to satisfy quasi-static solid mechanics equations subject to geometric or kinematic cons… more

Date: January 18, 2000

Creator: Baer, Thomas A.; Subia, Samuel R. & Sackinger, Philip A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A gas-flow source term from a nuclear waste container in an unsaturated medium

The potential nuclear waste repository at Yucca Mountain is to be in partially saturated rock. Released radioactive gases would have a direct pathway to the biosphere. The entry of air into spent fuel would promote the oxidation of uranium matrix to more soluble forms. For licensing, the waste package must provide for substantially complete containment of radionuclides, including gases, for 300 to 1000 years. For safety assessment, a gaseous source term is needed. Thus it is important to study … more

Date: August 1, 1989

Creator: Zwahlen, E. D.; Pigford, T. H.; Chambre, P. L. & Lee, W. W. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Analysis, scientific computing and fundamental studies in fluid mechanics. Final report Number 21, May 1, 1997--September 30, 1998

This report is a summary of work in progress and completed. Subject areas covered are: effective numerical methods for interfacial flows; multiscale finite element methods: analysis and applications; an efficient boundary integral method for the Mullins-Sekera problem; numerical simulation of three-dimensional water waves using a fast summation method; numerical solutions of steady-state rising bubbles; solidification coupled to fluid convection; turbulence models; exact solution of very viscou… more

Date: December 31, 1998

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Modeling, system identification, and control for slosh-free motion of an open container of liquid

This report discusses work performed under a Cooperative Research And Development Agreement (CRADA) with Corning, Inc., to analyze and test various techniques for controlling the motion of a high speed robotic arm carrying an open container of viscous liquid, in this case, molten glass. A computer model was generated to estimate the modes of oscillation of the liquid based on the shape of the container and the viscosity of the liquid. This fluid model was experimentally verified and tuned based… more

Date: April 1, 1996

Creator: Feddema, J.; Baty, R.; Dykhuizen, R.; Dohrmann, C.; Parker, G.; Robinett, R. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Dynamics of two coaxial cylindrical shells containing viscous fluid

This study was motivated by the need to design the thermal shield in reactor internals and other system components to avoid detrimental flow-induced vibrations. The system component is modeled as two coaxial shells separated by a viscous fluid. In the analysis, Flugge's shell equations of motion and linearized Navier-Stokes equation for viscous fluid are employed. First, a traveling-wave type solution is taken for shells and fluid. Then, from the interface conditions between the shells and flui… more

Date: September 1, 1976

Creator: Yeh, T. T. & Chen, S. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Impulse-based methods for fluid flow

A Lagrangian numerical method based on impulse variables is analyzed. A relation between impulse vectors and vortex dipoles with a prescribed dipole moment is presented. This relation is used to adapt the high-accuracy cutoff functions of vortex methods for use in impulse-based methods. A source of error in the long-time implementation of the impulse method is explained and two techniques for avoiding this error are presented. An application of impulse methods to the motion of a fluid surrounde… more

Date: May 1, 1995

Creator: Cortez, R.

Item Type: Thesis or Dissertation

Partner: UNT Libraries Government Documents Department

open access

An analysis of lift forces on aerosols in a wall bounded turbulent shear flow

This paper describes work that will lead to a better understanding of the role of lift forces in the deposition of aerosols on the walls bounding a turbulent shear flow. After providing some background information about aerosol trajectories that has been obtained from computer simulations, new results for the lift force in the relevant parameter ranges are presented.

Date: January 1, 1992

Creator: Cherukat, P. & McLaughlin, J. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Flow and plasticity via nonequilibrium molecular dynamics

The viscous flow of fluids and the plastic flow of solids, such as metals, are interesting from both the practical and the theoretical points of view. Atomistic molecular dynamics simulations provide a way of visualizing and understanding these flows in a detailed microscopic way. Simulations are necessarily carried out at relatively high rates of strain. For this reason they are ideally suited to the study of nonlinear flow phenomena: normal stresses induced by shear deformation, stress rotati… more

Date: June 11, 1984

Creator: Hoover, W. G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

HYDRA, A finite element computational fluid dynamics code: User manual

HYDRA is a finite element code which has been developed specifically to attack the class of transient, incompressible, viscous, computational fluid dynamics problems which are predominant in the world which surrounds us. The goal for HYDRA has been to achieve high performance across a spectrum of supercomputer architectures without sacrificing any of the aspects of the finite element method which make it so flexible and permit application to a broad class of problems. As supercomputer algorithm… more

Date: June 1, 1995

Creator: Christon, M. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Steady-State Thermomechanical Finite Element Analysis of Elastoviscoplastic Metal Forming Processes

Extrusion and rolling processes exhibiting large amounts of plastic flow are analyzed using a finite element technique that is based on a modified creeping viscous flow approximation. The technique, called the initial stress-rate method, iteratively corrects creeping viscous flow solutions to generate results that include elastic response. The momentum equations have been coupled with the energy equation to provide the capability to predict thermomechanical response during forming operations.

Date: January 1, 1977

Creator: Dawson, P.R. & Thompson, E.G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Resonator response to Non-Newtonian fluids

The thickness-shear mode (TSM) resonator typically consists of a thin disk of AT-cut quartz with circular electrodes patterned on both sides. An RF voltage applied between these electrodes excites a shear mode mechanical resonance when the excitation frequency matches the crystal resonant frequency. When the TSM resonator is operated in contact with a liquid, the shear motion of the surface generates motion in the contacting liquid. The liquid velocity field, v{sub x}(y), can be determined by s… more

Date: June 1, 1994

Creator: Martin, S. J.; Schneider, T. W.; Frye, G. C.; Cernosek, R. W. & Senturia, S. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Hydrodynamic particle migration in a concentrated suspension undergoing flow between rotating eccentric cylinders

We report on experimental measurements and numerical predictions of shear-induced migration of particles in concentrated suspensions subjected to flow in the wide gap between a rotating inner cylinder placed eccentrically within a fixed outer cylinder (a cylindrical bearing). The suspensions consists of large, noncolloidal spherical particles suspended in a viscous Newtonian liquid. Nuclear magnetic resonance (NMR) imaging is used to measure the time evolution of concentration and velocity prof… more

Date: July 1, 1995

Creator: Phan-Thien, Nhan; Graham, Alan L.; Abbott, James R.; Altobelli, Stephen A. & Mondy, Lisa A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Parallel spatial direct numerical simulation of boundary-layer flow transition on IBM SP1

The spatially evolving disturbances that are associated with laminar-to-turbulent transition in three-dimensional boundary-layer flows are computed with the PSDNS code on an IBM SP1 parallel supercomputer. By remapping the distributed data structure during the course of the calculation, optimized serial library routines can be utilized that substantially increase the computational performance. Although the remapping incurs a high communication penalty, the parallel efficiency of the code remain… more

Date: July 1, 1995

Creator: Hanebutte, U.R.; Joslin, R.D. & Zubair, M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

CO2 SEPARATIONS USING ZEOLITE MEMBRANES

Zeolite and other inorganic molecular sieve membranes have shown potential for separations based on molecular size and shape because of their small pore sized, typically less than 1 nm, and their narrow pore size distribution. The high thermal and chemical stability of these inorganic crystals make them ideal materials for use in high temperature applications such as catalytic membrane reactors. Most of the progress with zeolite membranes has been with MFI zeolites prepared on porous disks and … more

Date: June 30, 2001

Creator: Noble, Richard D. & Falconer, John L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Lance water injection tests adjacent to the 281-3H retention basin at the Savannah River Site, Aiken, South Carolina

A pilot-scale field demonstration of waste isolation using viscous- liquid containment barriers has been planned for the 281-3H retention basin at the Savannah River Site, Aiken, SC. The 281-3H basin is a shallow retention/seepage basin contaminated mainly by radionuclides. The viscous-liquid containment barrier utilizes the permeation of liquid grout to either entomb the contaminants within a monolithic grout structure or to isolate the waste by drastically reducing the permeability, of the so… more

Date: September 1, 1996

Creator: Freifeld, B.; Myer, L.; Moridis, G.; Cook, P.; James, A.; Pellerin, L. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Potential capabilities of Reynolds stress turbulence model in the COMMIX-RSM code

A Reynolds stress turbulence model has been implemented in the COMMIX code, together with transport equations describing turbulent heat fluxes, variance of temperature fluctuations, and dissipation of turbulence kinetic energy. The model has been verified partially by simulating homogeneous turbulent shear flow, and stable and unstable stratified shear flows with strong buoyancy-suppressing or enhancing turbulence. This article outlines the model, explains the verifications performed thus far, … more

Date: December 1, 1993

Creator: Chang, F. C. & Bottoni, M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

An embedded boundary method for the modeling of unsteady combustion in an industrial gas-fired furnace

A new methodology for the modeling of unsteady, nonpremixed, axisymmetric reacting flow in industrial furnaces is presented. The method is an extension of previous work by the authors to complex geometries, multistep kinetics mechanisms, and realistic properties, especially thermochemical data. The walls of the furnace are represented as an embedded boundary in a uniform, rectangular grid. The grid then consists of uniform rectangular cells except at the furnace wall where irregular (mixed) cel… more

Date: October 18, 1995

Creator: Pember, R. B.; Almgren, A. S.; Crutchfield, W. Y.; Howell, L. H.; Bell, J. B.; Colella, P. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A method and apparatus for continuous electrophoresis

A method and apparatus for conducting continuous separation of substances by electrophoresis are disclosed. The process involves electrophoretic separation combined with couette flow in a thin volume defined by opposing surfaces. By alternating the polarity of the applied potential and producing reciprocating short rotations of at least on of the surfaces relative to the other, small increments of separation accumulate to cause substantial, useful segregation of electrophoretically separable co… more

Date: January 1, 1990

Creator: Watson, J. S.

Item Type: Patent

Partner: UNT Libraries Government Documents Department

open access

Thinning and rupture of a thin liquid film on a heated surface. Progress report, October 1, 1989--September 30, 1990

The objective of this work continues to be the study of dynamics, stability, and rupture (including contact line motions) of thin liquid films, especially with heat and/or mass transfer. Following the publication of a comprehensive paper on thin-film stability and rupture, taking into account evaporation (condensation), thermocapillarity, surface tension, vapor recoil, van der Waals forces, and mass loss (gain), two follow-up papers have appeared. The first examines the conditions for a non-uni… more

Date: May 1, 1992

Creator: Bankoff, S. G. & Davis, S. H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Is there a statistical mechanics of turbulence

The statistical-mechanical treatment of turbulence is made questionable by strong nonlinearity and strong disequilibrium that result in the creation of ordered structures imbedded in disorder. Model systems are described which may provide some hope that a compact, yet faithful, statistical description of turbulence nevertheless is possible. Some essential dynamic features of the models are captured by low-order statistical approximations despite strongly non-Gaussian behavior. 31 refs., 5 figs.

Date: September 1, 1988

Creator: Kraichnan, R. H. & Chen, S. Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Surface path lines in plane stokes flow driven by capillarity

Consider the free creeping viscous plane flow in a region, bounded by a simple smooth closed curve and driven solely by surface tension. The shape evolution may in principle, and often in practice, be described by a time-dependent mapping z = {Omega}({zeta},t) of the unit circle, conformal on {vert_bar}{zeta}{vert_bar} {le} 1. It is shown that the path lines of fluid elements at the surface are determined by a first-order ordinary differential equation involving {Omega}({zeta},t), together with… more

Date: May 3, 1993

Creator: Hopper, R. W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

COUPLEFLO: a computer program for coupled creeping viscous flow and conductive-convective heat transfer. Part II. User's manual

COUPLEFLO is a two-dimensional finite element code for plane strain or axisymmetric analyses of thermomechanically coupled systems. It is capable of analyzing the creeping flow of non-Newtonian fluids or the secondary creep of solids. COUPLEFLO solves equations for conductive-convective heat transfer to determine the thermal response of a system. Thermomechanical coupling between the flow field and temperature distribution can exist in terms of temperature dependent material properties, tempera… more

Date: November 1, 1978

Creator: Chavez, P.F. & Dawson, P.R.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Thermodynamic and stochastic theory of hydrodynamic and power-producing processes. [Annual report], September 1991--September 1992

Thermodynamics of the transport processes of diffusion, thermal conduction, and viscous flow at a macroscopic level are developed for the simplest cases of one-dimensional transport in fluids for individual linear and nonlinear processes approaching a stationary non-equilibrium state. Formulation has started of thermodynamic and stochastic theory of combinations of transport processes. Global thermodynamic and stochastic theory of open chemical systems frar from equilibrium is continued with an… more

Date: September 16, 1992

Creator: Ross, J.

Item Type: Report

Partner: UNT Libraries Government Documents Department