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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 235 records · Page 13
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Jet Noise Modeling Using an Acoustic Analogy: From Theoretical Formulation to Practical Noise Predictions

In this presentation an overview of the development of an acoustic analogy formulation, and its implementation into a reduced-order prediction method for turbulent jet mixing noise, will be given. The definition and rationale of an acoustic analogy approach to the prediction of flow-generated noise will be provided. A high-level description of the mathematical processes involved will be outlined in the context of a particular formulation developed at NASA Glenn Research Center. The modelling approximations needed to implement the general theoretical formulation into a practical noise prediction tool will be discussed. Sample results obtained using a noise prediction code based on the NASA Glenn formulation, and comparisons with experimental data, will be presented for a series of turbulent jet test cases. A view on the prospects for continued use of acoustic analogy-based methods for the prediction of flow-generated noise and the assessment of noise-reduction technologies will conclude the presentation.

Jet noise↗
DOE OSTI2011

Reduced weight decontamination formulation utilizing a solid peracid compound for neutralization of chemical and biological warfare agents

A reduced weight decontamination formulation that utilizes a solid peracid compound (sodium borate peracetate) and a cationic surfactant (dodecyltrimethylammonium chloride) that can be packaged with all water removed. This reduces the packaged weight of the decontamination formulation by .about.80% (as compared to the "all-liquid" DF-200 formulation) and significantly lowers the logistics burden on the warfighter. Water (freshwater or saltwater) is added to the new decontamination formulation at the time of use from a local source.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

The WTP Immobilized LAW Formulation Algorithm: Recent Efforts Toward Software Development - 17342

The immobilized low-activity waste (ILAW) product from WTP must meet certain requirements and processing constraints. The strategy for controlling ILAW product composition uses the ILAW formulation algorithm. This algorithm is approved by the DOE Office of River Protection (ORP) for use in calculating melter feed recipes that will produce acceptable ILAW product during Low-Activity Waste (LAW) Facility commissioning. The calculations performed by the algorithm have been demonstrated using a sophisticated spreadsheet, but this spreadsheet is not expected to support continuous operation. Efforts are underway to develop software that will support glass formulation during operation. Recent work toward software development includes an examination of assumptions made in the algorithm about expected LAW Facility operation, and spreadsheet calculations to formulate glass for potential LAW compositions under the direct feed LAW (DFLAW) strategy that ORP has adopted. The documentation of the ILAW algorithm is the planned basis for software development. However, some assumptions made in the current algorithm's mass balance logic do not match the matured design and expected operation of the LAW Facility. A self-assessment effort evaluated the validity of these assumptions by reviewing design documents, in order to identify opportunities to align the algorithm's mass balance logic with the matured design and ensure that the developed software supports continuous LAW Facility operation. Several improvement opportunities were identified and are discussed. The results of ILAW algorithm calculations to formulate glass for eighteen challenging LAW compositions indicate that the current WTP baseline LAW glass models are sufficiently robust to accommodate DFLAW. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

New Formulation of Cast Stone for {sup 99}Tc Immobilization in Sulfate Rich Secondary Waste Stream - 16098

A low-temperature, cementitious waste form called Cast Stone (or grout) has been selected for solidification of the Effluent Treatment Facility (ETF)-treated wastes at the Hanford Site. Because the waste stream to be solidified may be relatively high in sulfate, the current Cast Stone dry blend formulation with ordinary Portland cement (OPC), fly ash (FA), and blast furnace slag (BFS) (47% BFS, 45% FA, and 8% OPC) may not be adequate. Thus a new formulation, called secondary waste grout, was proposed and tested. The secondary waste grout uses hydrated lime [Ca(OH){sub 2}] to tie up the sulfate initially such that ettringite [Ca{sub 6}Al{sub 2}(SO{sub 4}){sub 3}(OH){sub 12}.26(H{sub 2}O)] forms rapidly instead of forming as the cementitious waste form cures. Three different liquid waste simulants (242-A evaporator, Environmental Restoration Disposal Facility [ERDF] leachates, and Hanford Tank Waste Treatment and Immobilization Plant [WTP] off-gas condensates) were prepared and solidified using this new dry blend formulation. Baseline grout dry mixes were 20 wt% hydrated lime (HL), 35 wt% OPC, and 45 wt% BFS, and two different water-to-dry mix (w/dm) ratios (0.5 and 0.6) of free water mass to mass of dry blend were tested. After curing for a minimum of 28 days, the grout solidified waste forms were characterized and used for Tc leachability testing using the EPA 1315 Method. X-ray diffraction analysis confirmed that ∼12-15% of ettringite was formed in early stage of 28-day curing for the grouts prepared with the high sulfate WTP simulant and HL addition. In addition, the new formulation of secondary waste grout prepared with HL (20%), OPC (35%), and BFS (45%) at either 0.5 or 0.6 water to dry mix ratio yields higher average Tc interval leachability index (LI) values (12.5 to 13.9) after 28 to 90 days of leaching using deionized water, which is higher than the desired {sup 99}Tc LI value of 12 for grout destined for burial in the Integrated Disposal Facility at the Hanford Site. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

Comparative investigation of iterative solutions of the all-frequency stable formulation and its vector-potential-only variation

An all-frequency stable formulation has been proposed and applied to solve low-frequency and multiscale electromagnetic problems to avoid the low-frequency breakdown catastrophe of the traditional vector wave equation. Based on the potential representation of the fields, this formulation involves vector and scalar potentials, as well as an auxiliary potential to enforce the gauge condition. In this paper, such a formulation is first simplified to involve vector potential only. Their iterative solutions are then sought by using an incomplete LU preconditioner and an iterative solver. The iterative performance of both formulations are investigated in a comparative study.

Mekonnen, Minyechil↗
DOE OSTI2024

A simplified all-frequency stable formulation with an implicit Coulomb gauge

A potential-based finite element formulation has been developed in the past to circumvent the low-frequency breakdown issues commonly encountered in electromagnetic (EM) simulations of low-frequency and multiscale problems. In this formulation, the magnetic vector and electric scalar potentials have been employed to express the electric field and magnetic flux, leading to a set of two equations that represents all four Maxwell’s equations and the current continuity equation. To enforce the Coulomb gauge, an auxiliary potential has been introduced, which results in a total of three equations to be solved simultaneously. To reduce the number of equations and unknowns needed in a simulation, a simplified formulation is proposed in this paper to enforce the Coulomb gauge implicitly without the need for the auxiliary potential. A numerical example is given to demonstrate the accuracy of the proposed formulation.

Mekonnen, Minyechil↗
DOE OSTI2019

Antiwear Properties of Binary Ashless Blend of Phosphonium Ionic Liquids and Borate Esters in Partially Formulated Oil (No Zn)

Here, interaction of ionic liquid (IL) and borate esters (SBs) as antiwear (AW) additives with steel surfaces in tribological contacts was examined using blends which contained no prior AW additives but all the other ingredients present in a fully formulated engine oil. In detail, low phosphorus oil blends were prepared by adding trihexyltetradecylphosphonium bis(2-ethylhexyl)phosphate (P_DEHP) at 700ppm phosphorus and 2-methoxy-4,4,6-trimethyl-1,3,2-dioxaborinane or trimethoxyboroxine at 200ppm boron treat rate to a partially formulated oil. The tribological properties of these novel ionic liquid (IL) additive and IL+SB additive mixtures were compared with those of zinc dialkyldithiophosphate (ZDDP) at equal phosphorus levels in the oil blends. Tribological experiments with a reciprocating cylinder on flat contact revealed that both P_DEHP and binary mixtures of P_DEHP+SB offer superior wear protection than ZDDP and the partially formulated oil without AW additives, expressed by a wear reduction of minimum 50%. X-ray absorption near edge structure spectroscopy (XANES) analysis revealed that tribologically formed films are primarily composed of calcium phosphate for oils with AW additives. The interaction of P_DEHP with SB results in additional boron oxide/boric acid and to some extent boron phosphate domains incorporated into the tribofilms.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

An arbitrary Lagrangian–Eulerian finite element formulation for a poroelasticity problem stemming from mixture theory

In this paper, a finite element formulation is developed for a poroelastic medium consisting of an incompressible hyperelastic skeleton saturated by an incompressible fluid. The governing equations stem from mixture theory and the application is motivated by the study of interstitial fluid flow in brain tissue. The formulation is based on the adoption of an arbitrary Lagrangian–Eulerian (ALE) perspective. We focus on a flow regime in which inertia forces are negligible. Finally, the stability and convergence of the formulation is discussed, and numerical results demonstrate agreement with the theory.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2014

Compositional Models of Glass/Melt Properties and their Use for Glass Formulation

Nuclear waste glasses must simultaneously meet a number of criteria related to their processability, product quality, and cost factors. The properties that must be controlled in glass formulation and waste vitrification plant operation tend to vary smoothly with composition allowing for glass property-composition models to be developed and used. Models have been fit to the key glass properties. The properties are transformed so that simple functions of composition (e.g., linear, polynomial, or component ratios) can be used as model forms. The model forms are fit to experimental data designed statistically to efficiently cover the composition space of interest. Examples of these models are found in literature. The glass property-composition models, their uncertainty definitions, property constraints, and optimality criteria are combined to formulate optimal glass compositions, control composition in vitrification plants, and to qualify waste glasses for disposal. An overview of current glass property-composition modeling techniques is summarized in this paper along with an example of how those models are applied to glass formulation and product qualification at the planned Hanford high-level waste vitrification plant.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2012

Assessing Component Effects in Formulation Systems

The purpose of Snee (2011) was to discuss and illustrate how using Six Sigma concepts and approaches can lead to a better understanding of formulation systems. Central to the recommended approach is estimating and interpreting the effects of the components in the formulation on the response variable. Knowledge of components that have no effect, small or large effects (positive or negative), and similar effects is very helpful in understanding how the formulation system works. This understanding helps one decide 1) which components having large effects should be increased or decreased, and 2) what to do about components with no effects or similar effects. Correspondence between the authors following Snee (2011), along with further review of the literature, have pointed out that the approaches discussed in Snee (2011), and the interpretation of component effects in general, need further clarification. That is the focus of this article.

component effect directions↗
DOE OSTI2022

Extended Barton–Bandis model for rock joints under cyclic loading: Formulation and implicit algorithm

In this paper, the Barton–Bandis model for rock joints is extended to cyclic loading conditions, without any new material parameter. Also developed herein is an implicit solution algorithm for the extended Barton–Bandis model, which can also be used for the original Barton–Bandis model for which an implicit algorithm has been unavailable. To this end, we first cast the Barton–Bandis model into an incremental elasto-plastic framework, deriving an expression for the elastic shear stiffness being consistent with the original model formulation. We then extend the model formulation to cyclic loading conditions, incorporating the dependence of shear stress and dilation on the joint position and the shearing direction. The extension is achieved by introducing a few state-dependent variables which can be calculated with the existing material parameters. For robust and accurate utilization of the model, we also develop an implicit algorithm based on return mapping, which is unconditionally stable and guarantees the satisfaction of the strength criterion. We verify that the proposed model formulation and algorithm produce virtually the same results as the original Barton–Bandis model under monotonic shearing conditions. Here, we then validate the extended Barton–Bandis model against experimental data on natural rock joints under cycling loading conditions. The present work thus enables the Barton–Bandis model, which has been exceptionally popular in research and practice, to be applicable to a wider range of problems in rock mechanics and rock engineering.

58 GEOSCIENCES↗
DOE OSTI2023

Shear and combustion characterization of printable ammonium perchlorate composite propellant formulations

Seven formulations of ammonium perchlorate composite propellant (APCP) are developed and their properties relevant for successful additive manufacture are characterized. Extrusion in a custom-built 3D printing system and spindle viscometry are used to collect viscosity measurements of curing primary and non-curing secondary versions of the formulations. The formulations that behave similarly to a Bingham plastic, with apparent viscosities between 4 and 8 thousand Pa*s at 30 minutes post-mix, are determined to be most suitable for printing applications. Measurements of one material show a yield stress of 1 kPa. Ambient pressure burn rates of 2.0–2.9 mm/s were measured for the compositions tested. All measured burn rates were comparable to the lower end of typical burn rates for APCP. In conclusion, the results of the characterization demonstrate a propellant suitable for use in a 3D printing system.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

A time‐varying formulation of the curled wake model within the FAST.Farm framework

Abstract In this article, we present a time‐varying formulation of the curled wake model that we implemented in FAST.Farm. The curled wake model, originally developed for steady‐state conditions, is used to produce realistic wake profiles behind a wind turbine in yawed (or skewed) conditions. We begin by introducing the key elements of the FAST.Farm framework. Then, after briefly summarizing the original wake dynamics formulation of FAST.Farm based on a polar wake profile, we present the new time‐varying formulation of the curled wake model, compare the two, and highlight the differences with the original curled wake model. After discussing some implementation details, we present different applications with increasing levels of complexity: single turbine with uniform and turbulent inflow, fixed and transient yaw, and multiple turbines. We verify our results using the original FAST.Farm implementation and large‐eddy simulations. The results with the new curled wake model are improved compared to the original implementation, as they include cross‐flow velocities and wake asymmetry. Yet, large‐eddy simulation results show a more pronounced lateral convection of the wake and a stronger concentration of vorticity at the top vortex. The new curled wake implementation in FAST.Farm should enable the calculation of not only generator power but also wind turbine structural loads for applications involving intentional or unintentional skewed flow and wind‐farm control involving wake steering.

17 WIND ENERGY↗
DOE OSTI2018

Polycrystal Plasticity Models Based on Green’s Functions: Mean-Field Self-Consistent and Full-Field Fast Fourier Transform Formulations

We review two crystal plasticity methodologies based on Green’s functions for the prediction of microstructure-property relations in polycrystalline aggregates. The first, known as the viscoplastic self-consistent (VPSC) formulation, is a mean-field theory. The second, known as the viscoplastic fast Fourier transform-based (VPFFT) formulation, is a full-field method. Finally, the assumptions and main equations of these Green’s function-based crystal plasticity formulations are presented using a unified notation, pointing out their similarities and differences and cross-validating their predictions.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Note on two formulations of Crank-Nicolson method for Navier-Stokes equations

Here, we consider two formulations of the Crank-Nicolson (CN) method for the Navier-Stokes equations (NSE). The “natural” way of implementing CN for NSE is formally second order accurate in time for both velocity and pressure, whereas another formulation approximates pressure with only first order accuracy in time. Both versions of the method are applied to the benchmark problem of computing drag and lift in the flow around a cylinder. We show that the presumably more accurate version of the CN can create a solution with nonphysical oscillations and give incorrect predictions for the maximal drag coefficient, whereas the other formulation of the method predicts the drag and lift coefficients more accurately and does not introduce nonphysical oscillations. We locate the source of the issue and suggest several remedies.

Crank-Nicolson↗
DOE OSTI2010

Fundamental theories of waves and particles formulated without classical mass

Quantum and classical mechanics are two conceptually and mathematically different theories of physics, and yet they do use the same concept of classical mass that was originally introduced by Newton in his formulation of the laws of dynamics. In this paper, physical consequences of using the classical mass by both theories are explored, and a novel approach that allows formulating fundamental (Galilean invariant) theories of waves and particles without formally introducing the classical mass is presented. In this new formulation, the theories depend only on one common parameter called 'wave mass', which is deduced from experiments for selected elementary particles and for the classical mass of one kilogram. It is shown that quantum theory with the wave mass is independent of the Planck constant and that higher accuracy of performing calculations can be attained by such theory. Natural units in connection with the presented approach are also discussed and justification beyond dimensional analysis is given for the particular choice of such units.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Relativistic wave and particle mechanics formulated without classical mass

Highlights: > Formal derivation of the Klein-Gordon equation with an invariant frequency. > Formal derivation of the relativistic version of Newton's equation. > The classical mass is replaced by the invariant frequency. > The invariant frequencies for selected elementary particles are deduced. > The choice of natural units resulting from the developed theories is discussed. - Abstract: The fact that the concept of classical mass plays an important role in formulating relativistic theories of waves and particles is well-known. However, recent studies show that Galilean invariant theories of waves and particles can be formulated with the so-called 'wave mass', which replaces the classical mass and allows attaining higher accuracy of performing calculations [J.L. Fry and Z.E. Musielak, Ann. Phys. 325 (2010) 1194]. The main purpose of this paper is to generalize these results and formulate fundamental (Poincare invariant) relativistic theories of waves and particles without the classical mass. In the presented approach, the classical mass is replaced by an invariant frequency that only involves units of time. The invariant frequencies for various elementary particles are deduced from experiments and their relationship to the corresponding classical and wave mass for each particle is described. It is shown that relativistic wave mechanics with the invariant frequency is independent of the Planck constant, and that such theory can attain higher accuracy of performing calculations. The choice of natural units resulting from the developed theories of waves and particles is also discussed.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Hamiltonian formulation of systems with balanced loss–gain and exactly solvable models

A Hamiltonian formulation of generic many-body systems with balanced loss and gain is presented. It is shown that a Hamiltonian formulation is possible only if the balancing of loss and gain terms occurs in a pairwise fashion. It is also shown that with the choice of a suitable co-ordinate, the Hamiltonian can always be reformulated in the background of a pseudo-Euclidean metric. If the equations of motion of some of the well-known many-body systems like Calogero models are generalized to include balanced loss and gain, it appears that the same may not be amenable to a Hamiltonian formulation. A few exactly solvable systems with balanced loss and gain, along with a set of integrals of motion are constructed. The examples include a coupled chain of nonlinear oscillators and a many-particle Calogero-type model with four-body inverse square plus two-body pair-wise harmonic interactions. For the case of nonlinear oscillators, stable solution exists even if the loss and gain parameter has unbounded upper range. Further, the range of the parameter for which the stable solutions are obtained is independent of the total number of the oscillators. The set of coupled nonlinear equations are solved exactly for the case when the values of all the constants of motions except the Hamiltonian are equal to zero. Exact, analytical classical solutions are presented for all the examples considered.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗