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Correlations involving pressure fluctuations in homogeneous turbulence

Description: Report presenting an investigation of the correlations of pressure with itself and of pressure with two velocity components for the case of isotropic turbulence. The correlations are expressed in terms of correlations involving two velocity components at a point and two velocity components at another point.
Date: January 1954
Creator: Uberoi, Mahinder S.
Partner: UNT Libraries Government Documents Department

Some Problems on the Lift and Rolling Moment of Airplane Wings

Description: This report deals with the application of the airfoil and twisted wing theory to the calculation of the lift and rolling moment of airplane wings. Most of the results arrived at are strictly true only for wings of elliptic plan form. The investigation aims to give some indications of the accuracy with which the results can be applied to the wing forms in actual use.
Date: 1925
Creator: Scarborough, James B.
Partner: UNT Libraries Government Documents Department

Development of Turbulence-Measuring Equipment

Description: "Hot wire turbulence-measuring equipment has been developed to meet the more stringent requirements involved in the measurement of fluctuations in flow parameters at supersonic velocities. The higher mean speed necessitates the resolution of higher frequency components than at low speed, and the relatively low turbulence level present at supersonic speed makes necessary an improved noise level for the equipment. The equipment covers the frequency range from 2 to about 70,000 cycles per second" (p. 1).
Date: 1954
Creator: Kovasznay, Leslie S. G.
Partner: UNT Libraries Government Documents Department

Diffusion of heat from a line source in isotropic turbulence

Description: "An experimental and analytical study has been made of some features of the turbulent heat diffusion behind a line heated wire stretched perpendicular to a flowing isotropic turbulence. The mean temperature distributions have been measured with systematic variations in wind speed, size of turbulence-producing grid, and downstream location of heat source. The nature of the temperature fluctuation field has been studied" (p. 1).
Date: June 5, 1951
Creator: Uberoi, Mahinder S. & Corrsin, Stanley
Partner: UNT Libraries Government Documents Department

Spectra and diffusion in a round turbulent jet

Description: "In a round turbulent jet at room temperature, measurement of the shear correlation coefficient as a function of frequency (through band-pass filters) has given a rather direct verification of Kolmogoroff's local-isotropy hypothesis. One-dimensional power spectra of velocity and temperature fluctuations, measured in unheated and heated jets, respectively, have been contrasted. Under the same conditions, the two corresponding transverse correlation functions have been measured and compared" (p. 1).
Date: August 17, 1949
Creator: Corrsin, Stanley & Uberoi, Mahinder S.
Partner: UNT Libraries Government Documents Department

Spectrums and diffusion in a round turbulent jet

Description: "In a round turbulent jet at room temperature, measurement of the shear correlation coefficient as a function of frequency (through bandpass filters) has given a rather direct verification of Kolmogoroff's local-isotropy hypothesis. One-dimensional power spectrums of velocity and temperature fluctuations, measured in unheated and heated jets, respectively, have been contrasted. Under the same conditions, the two corresponding transverse correlation functions have been measured and compared" (p. 1).
Date: July 1950
Creator: Corrsin, Stanley & Uberoi, Mahinder S.
Partner: UNT Libraries Government Documents Department

Free-Stream Boundaries of Turbulent Flows

Description: Report presents the results of an experimental and theoretical study made of the instantaneously sharp and irregular front which is always found to separate turbulent fluid from contiguous "nonturbulent" fluid at a free-stream boundary. This distinct demarcation is known to give an intermittent character to hot-wire signals in the boundary zone. The overall behavior of the front is described statistically in terms of its wrinkle-amplitude growth and its lateral propagation relative to the fluid as functions of downstream coordinate.
Date: 1955
Creator: Corrsin, Stanley & Kistler, Alan L.
Partner: UNT Libraries Government Documents Department

Geothermal Energy Market Study on the Atlantic Coastal Plain. The Demand Specified Model for Direct Applications of Geothermal Energy: A User's Guide

Description: The Applied Physics Laboratory and the Center for Metropolitan Planning and Research of The Johns Hopkins University support the Department of Energy's Division of Geothermal Energy (DOE/DGE) in planning and assisting the development of geothermal energy in the eastern United States. This effort includes development scenarios, energy market surveys, development of tools to analyze and optimize the cost of geothermal energy, the methodology for prediction of market penetration technical assistance to states, groups, and individuals and general support to DOE/DGE. This report documents one of the economic tools developed under that program. Related reports are listed as references.
Date: December 1, 1980
Creator: Kroll, Peter; Barron, William F. & Toth, William J.
Partner: UNT Libraries Government Documents Department

The Effect of Hydrogen on the Stability of, and the Stabilization of Perfluoro Oils Toward Fluorine

Description: The following report discusses methods developed through various investigations on the effect of hydrogen on the stability and stabilization of perfluoro oils toward fluorine, using compounds of carbon and fluorine or "perfluorocarbons" as the subject of study.
Date: 1952
Creator: Weber, C. E.
Partner: UNT Libraries Government Documents Department

Local Isotropy in Turbulent Shear Flow

Description: "The mean strain rate in turbulent shear flow must tend to make the structure anisotropic in all parts of the spectrum. It is argued here, however, that if the spectral energy transfer process destroys orientation, the Kolmogoroff notion of local isotropy can still be justified in spectral regions where the local transfer time is shorter than the characteristics time of the gross shear strain" (p. 1).
Date: May 28, 1958
Creator: Corrsin, Stanley
Partner: UNT Libraries Government Documents Department

Heat Transfer in Isotropic Turbulence During the Final Period of Decay

Description: Note presenting a consideration of the problem of heat transfer in isotropic turbulence with a constant mean temperature gradient during the final period of decay. The temperature field is ultimately found to become independent of the initial conditions on the temperature and have characteristics determined only by the mean temperature gradient, the physical properties of the fluid, and the characteristics of the turbulence.
Date: June 1958
Creator: Dunn, D. W. & Reid, W. H.
Partner: UNT Libraries Government Documents Department

Influence of Solid-Body Rotation on Screen-Produced Turbulence

Description: Note presenting an investigation of the influence of solid-body rotation on a screen-produced turbulence in a flow between concentric, rotating cylinders. Radial distributions of the three components of turbulence intensity and the three turbulent shear stresses were measured at a fixed distance downstream of the screen both with and without rotation.
Date: August 1958
Creator: Traugott, Stephen C.
Partner: UNT Libraries Government Documents Department

Stability of Systems Containing a Heat Source - The Rayleigh Criterion

Description: "The stability of systems containing a heat source is examined from the energy point of view. Rayleigh's criterion is derived. In the case of a flame, it is found that Rayleigh's criterion must be modified slightly if the specific-heat ratios of the burned and unburned gases are different" (p. 1).
Date: June 26, 1956
Creator: Chu, Boa-Teh
Partner: UNT Libraries Government Documents Department

Some Exact Solutions of Two-Dimensional Flows of Compressible Fluid With Hodograph Method

Description: Note presenting a suggestion for classifying the compressible potential flows according to the location and number of singularities in the subsonic region of the hodograph plane, which seems to offer a convenient criterion for systematic investigation of these flows with Chaplygin's original method. The primary object of the paper is to present and analyze a few useful solutions of compressible potential flow with the exact gas law.
Date: February 1953
Creator: Chang, Chien-Chien & O'Brien, Vivian
Partner: UNT Libraries Government Documents Department

Uncertainty quantification in reacting flow modeling.

Description: Uncertainty quantification (UQ) in the computational modeling of physical systems is important for scientific investigation, engineering design, and model validation. In this work we develop techniques for UQ based on spectral and pseudo-spectral polynomial chaos (PC) expansions, and we apply these constructions in computations of reacting flow. We develop and compare both intrusive and non-intrusive spectral PC techniques. In the intrusive construction, the deterministic model equations are reformulated using Galerkin projection into a set of equations for the time evolution of the field variable PC expansion mode strengths. The mode strengths relate specific parametric uncertainties to their effects on model outputs. The non-intrusive construction uses sampling of many realizations of the original deterministic model, and projects the resulting statistics onto the PC modes, arriving at the PC expansions of the model outputs. We investigate and discuss the strengths and weaknesses of each approach, and identify their utility under different conditions. We also outline areas where ongoing and future research are needed to address challenges with both approaches.
Date: October 1, 2003
Creator: Le MaÒitre, Olivier P. (UniversitÔe d'Evry Val d'Essonne, Evry, France); Reagan, Matthew T.; Knio, Omar M. (Johns Hopkins University, Baltimore, MD); Ghanem, Roger Georges (Johns Hopkins University, Baltimore, MD) & Najm, Habib N.
Partner: UNT Libraries Government Documents Department

Molecular dynamics of membrane proteins.

Description: Understanding the dynamics of the membrane protein rhodopsin will have broad implications for other membrane proteins and cellular signaling processes. Rhodopsin (Rho) is a light activated G-protein coupled receptor (GPCR). When activated by ligands, GPCRs bind and activate G-proteins residing within the cell and begin a signaling cascade that results in the cell's response to external stimuli. More than 50% of all current drugs are targeted toward G-proteins. Rho is the prototypical member of the class A GPCR superfamily. Understanding the activation of Rho and its interaction with its Gprotein can therefore lead to a wider understanding of the mechanisms of GPCR activation and G-protein activation. Understanding the dark to light transition of Rho is fully analogous to the general ligand binding and activation problem for GPCRs. This transition is dependent on the lipid environment. The effect of lipids on membrane protein activity in general has had little attention, but evidence is beginning to show a significant role for lipids in membrane protein activity. Using the LAMMPS program and simulation methods benchmarked under the IBIG program, we perform a variety of allatom molecular dynamics simulations of membrane proteins.
Date: October 1, 2004
Creator: Woolf, Thomas B. (Johns Hopkins University School of Medicine, Baltimore, MD); Crozier, Paul Stewart & Stevens, Mark Jackson
Partner: UNT Libraries Government Documents Department

A numerical scheme for modelling reacting flow with detailed chemistry and transport.

Description: An efficient projection scheme is developed for the simulation of reacting flow with detailed kinetics and transport. The scheme is based on a zero-Mach-number formulation of the compressible conservation equations for an ideal gas mixture. It is a modified version of the stiff operator-split scheme developed by Knio, Najm & Wyckoff (1999, J. Comput. Phys. 154, 428). Similar to its predecessor, the new scheme relies on Strang splitting of the discrete evolution equations, where diffusion is integrated in two half steps that are symmetrically distributed around a single stiff step for the reaction source terms. The diffusive half-step is integrated using an explicit single-step, multistage, Runge-Kutta-Chebyshev (RKC) method, which replaces the explicit, multi-step, fractional sub-step approach used in the previous formulation. This modification maintains the overall second-order convergence properties of the scheme and enhances the efficiency of the computations by taking advantage of the extended real-stability region of the RKC scheme. Two additional efficiency-enhancements are also explored, based on an extrapolation procedure for the transport coefficients and on the use of approximate Jacobian data evaluated on a coarse mesh. By including these enhancement schemes, performance tests using 2D computations with a detailed C{sub 1}C{sub 2} methane-air mechanism and a detailed mixture-averaged transport model indicate that speedup factors of about 15 are achieved over the previous split-stiff scheme.
Date: September 1, 2003
Creator: Knio, Omar M. (The Johns Hopkins University, Baltimore, MD); Najm, Habib N. & Paul, Phillip H. (Eksigent Technologies LLC, Livermore, CA)
Partner: UNT Libraries Government Documents Department

Substructured multibody molecular dynamics.

Description: We have enhanced our parallel molecular dynamics (MD) simulation software LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator, lammps.sandia.gov) to include many new features for accelerated simulation including articulated rigid body dynamics via coupling to the Rensselaer Polytechnic Institute code POEMS (Parallelizable Open-source Efficient Multibody Software). We use new features of the LAMMPS software package to investigate rhodopsin photoisomerization, and water model surface tension and capillary waves at the vapor-liquid interface. Finally, we motivate the recipes of MD for practitioners and researchers in numerical analysis and computational mechanics.
Date: November 1, 2006
Creator: Grest, Gary Stephen; Stevens, Mark Jackson; Plimpton, Steven James; Woolf, Thomas B. (Johns Hopkins University, Baltimore, MD); Lehoucq, Richard B.; Crozier, Paul Stewart et al.
Partner: UNT Libraries Government Documents Department

Nanomechanics of hard films on compliant substrates.

Description: Development of flexible thin film systems for biomedical, homeland security and environmental sensing applications has increased dramatically in recent years [1,2,3,4]. These systems typically combine traditional semiconductor technology with new flexible substrates, allowing for both the high electron mobility of semiconductors and the flexibility of polymers. The devices have the ability to be easily integrated into components and show promise for advanced design concepts, ranging from innovative microelectronics to MEMS and NEMS devices. These devices often contain layers of thin polymer, ceramic and metallic films where differing properties can lead to large residual stresses [5]. As long as the films remain substrate-bonded, they may deform far beyond their freestanding counterpart. Once debonded, substrate constraint disappears leading to film failure where compressive stresses can lead to wrinkling, delamination, and buckling [6,7,8] while tensile stresses can lead to film fracture and decohesion [9,10,11]. In all cases, performance depends on film adhesion. Experimentally it is difficult to measure adhesion. It is often studied using tape [12], pull off [13,14,15], and peel tests [16,17]. More recent techniques for measuring adhesion include scratch testing [18,19,20,21], four point bending [22,23,24], indentation [25,26,27], spontaneous blisters [28,29] and stressed overlayers [7,26,30,31,32,33]. Nevertheless, sample design and test techniques must be tailored for each system. There is a large body of elastic thin film fracture and elastic contact mechanics solutions for elastic films on rigid substrates in the published literature [5,7,34,35,36]. More recent work has extended these solutions to films on compliant substrates and show that increasing compliance markedly changes fracture energies compared with rigid elastic solution results [37,38]. However, the introduction of inelastic substrate response significantly complicates the problem [10,39,40]. As a result, our understanding of the critical relationship between adhesion, properties, and fracture for hard films on compliant substrates is limited. To address this issue, we integrated nanomechanical ...
Date: September 1, 2009
Creator: Reedy, Earl David, Jr. (Sandia National Laboratories, Albuquerque, NM); Emerson, John Allen (Sandia National Laboratories, Albuquerque, NM); Bahr, David F. (Washington State University, Pullman, WA); Moody, Neville Reid; Zhou, Xiao Wang; Hales, Lucas (University of Minnesota, Minneapolis, MN) et al.
Partner: UNT Libraries Government Documents Department

Recent developments on the STAR detector system at RHIC

Description: The STAR detector system is designed to provide tracking, momentum analysis and particle identification for many of the mid-rapidity charged particles produced in collisions at the RHIC collider. A silicon vertex detector (SVT) provides three layers of tracking near the interaction point. This is followed by the main time projection chamber (TPC), which continues tracking out to 200 cm radial distance from the interaction region. The detector design also includes an electromagnetic calorimeter, various trigger detectors, and radial TPCs in the forward region. The entire system is enclosed in a 0.5 T solenoid magnet. A progress report is given for the various components of the STAR detector system. The authors report on the recent developments in the detector proto-typing and construction, with an emphasis on the main TPC, recent TPC cosmic ray testing and shipping to Brookhaven National Laboratory.
Date: December 1997
Creator: Argonne National Laboratory
Partner: UNT Libraries Government Documents Department

The STAR Time Project Chamber

Description: Paper presented at the International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (1999) reporting on the progress of the STAR experiment, a complex system of many detector sub-systems which have been installed in a large solenoidal magnet at the Relativistic Heavy Ion Collider (RHIC).
Date: May 10, 1999
Creator: Argonne National Laboratory
Partner: UNT Libraries Government Documents Department