Vehicle Technologies Office Merit Review 2015: Large Eddy Simulation...
Office of Environmental Management (EM)
Large Eddy Simulation (LES) Applied to Advanced Engine Combustion Research Vehicle Technologies Office Merit Review 2015: Large Eddy Simulation (LES) Applied to Advanced Engine...
Large Eddy Simulation (LES) Applied to Advanced Engine Combustion...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Advanced Engine Combustion Research Large Eddy Simulation (LES) Applied to Advanced Engine Combustion Research 2012 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies...
Large Eddy Simulation (LES) Applied to LTC/Diesel/Hydrogen Engine...
Office of Environmental Management (EM)
Large Eddy Simulation (LES) Applied to LTCDieselHydrogen Engine Combustion Research Large Eddy Simulation (LES) Applied to LTCDieselHydrogen Engine Combustion Research 2009 DOE...
Large-Eddy Simulation of Wind-Plant Aerodynamics: Preprint
Churchfield, M. J.; Lee, S.; Moriarty, P. J.; Martinez, L. A.; Leonardi, S.; Vijayakumar, G.; Brasseur, J. G.
2012-01-01T23:59:59.000Z
In this work, we present results of a large-eddy simulation of the 48 multi-megawatt turbines composing the Lillgrund wind plant. Turbulent inflow wind is created by performing an atmospheric boundary layer precursor simulation and turbines are modeled using a rotating, variable-speed actuator line representation. The motivation for this work is that few others have done wind plant large-eddy simulations with a substantial number of turbines, and the methods for carrying out the simulations are varied. We wish to draw upon the strengths of the existing simulations and our growing atmospheric large-eddy simulation capability to create a sound methodology for performing this type of simulation. We have used the OpenFOAM CFD toolbox to create our solver.
Large-eddy simulation of multiphase flows in complex combustors
Mahesh, Krishnan
Large-eddy simulation of multiphase flows in complex combustors S. V. Apte1 , K. Mahesh2 , F. Ham1 to accurately predict reacting multi-phase flows in practical combustors involving complex physical phenomena-turbine combustor geometries to evaluate the predictions made for multiphase, turbulent flow. 1 Introduction
Adaptively refined large eddy simulations of clusters
Maier, A; Schmidt, W; Niemeyer, J C
2009-01-01T23:59:59.000Z
We present a numerical scheme for modelling unresolved turbulence in cosmological adaptive mesh refinement codes. As a first application, we study the evolution of turbulence in the intra-cluster medium and in the core of a galaxy cluster. Simulations with and without subgrid scale model are compared in detail. Since the flow in the ICM is subsonic, the global turbulent energy contribution at the unresolved length scales is smaller than 1% of the internal energy. We find that the production of turbulence is closely correlated with merger events occurring in the cluster environment, and its dissipation locally affects the cluster energy budget. Because of this additional source of dissipation, the core temperature is larger and the density is smaller in the presence of subgrid scale turbulence than in the standard adiabatic run, resulting in a higher entropy core value.
Applications of large eddy simulation methods to gyrokinetic turbulence
Bañón Navarro, A., E-mail: alejandro.banon.navarro@ipp.mpg.de; Happel, T. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)] [Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-85748 Garching (Germany); Teaca, B. [Applied Mathematics Research Centre, Coventry University, Coventry CV1 5FB (United Kingdom) [Applied Mathematics Research Centre, Coventry University, Coventry CV1 5FB (United Kingdom); Max-Planck für Sonnensystemforschung, Max-Planck-Str. 2, D-37191 Katlenburg-Lindau (Germany); Max-Planck/Princeton Center for Plasma Physics (Germany); Jenko, F. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-85748 Garching (Germany) [Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-85748 Garching (Germany); Max-Planck/Princeton Center for Plasma Physics (Germany); Hammett, G. W. [Max-Planck/Princeton Center for Plasma Physics, Princeton Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey 08543 (United States)] [Max-Planck/Princeton Center for Plasma Physics, Princeton Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey 08543 (United States); Collaboration: ASDEX Upgrade Team
2014-03-15T23:59:59.000Z
The large eddy simulation (LES) approach—solving numerically the large scales of a turbulent system and accounting for the small-scale influence through a model—is applied to nonlinear gyrokinetic systems that are driven by a number of different microinstabilities. Comparisons between modeled, lower resolution, and higher resolution simulations are performed for an experimental measurable quantity, the electron density fluctuation spectrum. Moreover, the validation and applicability of LES is demonstrated through a series of diagnostics based on the free energetics of the system.
Large Eddy Simulation (LES) Applied to Low-Temperature and Diesel...
Broader source: Energy.gov (indexed) [DOE]
Combustion Research Large Eddy Simulation (LES) Applied to Low-Temperature and Diesel Engine Combustion Research 2011 DOE Hydrogen and Fuel Cells Program, and Vehicle...
Hydrodynamic and hydromagnetic energy spectra from large eddy simulations
N. E. L. Haugen; A. Brandenburg
2006-06-29T23:59:59.000Z
Direct and large eddy simulations of hydrodynamic and hydromagnetic turbulence have been performed in an attempt to isolate artifacts from real and possibly asymptotic features in the energy spectra. It is shown that in a hydrodynamic turbulence simulation with a Smagorinsky subgrid scale model using 512^3 meshpoints two important features of the 4096^3 simulation on the Earth simulator (Kaneda et al. 2003, Phys. Fluids 15, L21) are reproduced: a k^{-0.1} correction to the inertial range with a k^{-5/3} Kolmogorov slope and the form of the bottleneck just before the dissipative subrange. Furthermore, it is shown that, while a Smagorinsky-type model for the induction equation causes an artificial and unacceptable reduction in the dynamo efficiency, hyper-resistivity yields good agreement with direct simulations. In the large-scale part of the inertial range, an excess of the spectral magnetic energy over the spectral kinetic energy is confirmed. However, a trend towards spectral equipartition at smaller scales in the inertial range can be identified. With magnetic fields, no explicit bottleneck effect is seen.
Implicit Large Eddy Simulation of Cavitation in Micro Channel Flows
Hickel, S; Schmidt, S J
2014-01-01T23:59:59.000Z
We present a numerical method for Large Eddy Simulations (LES) of compressible two-phase flows. The method is validated for the flow in a micro channel with a step-like restriction. This setup is representative for typical cavitating multi-phase flows in fuel injectors and follows an experimental study of Iben et al., 2010. While a diesel-like test fuel was used in the experiment, we solve the compressible Navier-Stokes equations with a barotropic equation of state for water and vapor and a simple phase-change model based on equilibrium assumptions. Our LES resolve all wave dynamics in the compressible fluid and the turbulence production in shear layers.
Mesoscale and Large-Eddy Simulations for Wind Energy
Marjanovic, N
2011-02-22T23:59:59.000Z
Operational wind power forecasting, turbine micrositing, and turbine design require high-resolution simulations of atmospheric flow over complex terrain. The use of both Reynolds-Averaged Navier Stokes (RANS) and large-eddy (LES) simulations is explored for wind energy applications using the Weather Research and Forecasting (WRF) model. To adequately resolve terrain and turbulence in the atmospheric boundary layer, grid nesting is used to refine the grid from mesoscale to finer scales. This paper examines the performance of the grid nesting configuration, turbulence closures, and resolution (up to as fine as 100 m horizontal spacing) for simulations of synoptically and locally driven wind ramping events at a West Coast North American wind farm. Interestingly, little improvement is found when using higher resolution simulations or better resolved turbulence closures in comparison to observation data available for this particular site. This is true for week-long simulations as well, where finer resolution runs show only small changes in the distribution of wind speeds or turbulence intensities. It appears that the relatively simple topography of this site is adequately resolved by all model grids (even as coarse as 2.7 km) so that all resolutions are able to model the physics at similar accuracy. The accuracy of the results is shown in this paper to be more dependent on the parameterization of the land-surface characteristics such as soil moisture rather than on grid resolution.
Flame Stability Analysis in an Ultra Compact Combustor Using Large-Eddy Simulation
Raman, Venkat
Flame Stability Analysis in an Ultra Compact Combustor Using Large-Eddy Simulation C. Lietz , C Base, Ohio 45433 Large eddy simulation (LES) of an experimental ultra-compact combustor (UCC as a conven- tional combustor path. In order to reduce the penalty due to increased weight of these burners
Large-eddy simulation of swirling particle-laden flows in a coaxial-jet combustor
Apte, Sourabh V.
Large-eddy simulation of swirling particle-laden flows in a coaxial-jet combustor S.V. Apte a,* , K 2003 Abstract Large-eddy simulation (LES) of particle-laden, swirling flow in a coaxial-jet combustor;cyclone combustors, and biomass gasifiers (Lefebvre, 1989). The physics of such flows is extremely complex
Study of natural ventilation in buildings by large eddy simulation Yi Jiang and Qingyan Chen*
Chen, Qingyan "Yan"
1 Study of natural ventilation in buildings by large eddy simulation Yi Jiang and Qingyan Chen 02139 *Phone: (617) 253-7714, Fax: (617) 253-6152, Email: qchen@mit.edu Abstract Natural ventilation in the mechanical ventilation systems. Two subgrid-scale models of large eddy simulation (LES), a Smagorinsky
Large-eddy simulation of a wind turbine wake in turbulent
Firestone, Jeremy
Large-eddy simulation of a wind turbine wake in turbulent neutral shear flow Shengbai Xie, Cristina-similar velocity profile existing in the wake after a wind turbine? How does the wake influence the vertical? Motivation #12; Large-eddy simulation for turbulent flow field Actuator-line model for wind turbine ui
Measurements and large eddy simulation of propagating premixed flames
Masri, A.R.; Cadwallader, B.J. [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006 (Australia); Ibrahim, S.S. [Department of Aeronautical and Automotive Engineering, Loughborough University, Loughborough LE11 3TU (United Kingdom)
2006-07-15T23:59:59.000Z
This paper presents an experimental and numerical study of unsteady turbulent premixed flames igniting in an initially stagnant mixture and propagating past solid obstacles. The objective here is to study the outstanding issue of flow-flame interactions in transient premixed combustion environments. Particular emphasis is placed on the burning rate and the structure of the flame front. The experimental configuration consists of a chamber with a square cross-section filled with a combustible mixture of propane-air ignited from rest. An array of baffle plates as well as geometrical obstructions of varying shapes and blockage ratios, are placed in the path of the flame as it propagates from the ignition source to the vented end of the enclosure. A range of flame propagation conditions are studied experimentally. Measurements are presented for pressure-time traces, high-speed images of the flame front, mean velocities obtained from particle imaging velocimetry and laser induced fluorescence images of the hydroxyl radical OH. Three-dimensional large eddy simulations (LES) are also made for a case where a square obstacle and an array of baffle plates are placed in the chamber. The dynamic Germano model and a simple flamelet combustion model are used at the sub-grid scale. The effects of grid size and sub-grid filter width are also discussed. Calculations and measurements are found to be in good agreement with respect to flame structure and peak overpressure. Turbulence levels increase significantly at the leading edge of the flame as it propagates past the array of baffle plates and the obstacle. With reference to the regime diagrams for turbulent premixed combustion, it is noted that the flame continues to lie in the zones of thin reactions or corrugated flamelets regardless of the stage of propagation along the chamber. (author)
Large-Eddy Simulation of Flow and Pollutant Transport in Urban Street Canyons with Ground Heating
Li, Xian-Xiang
Our study employed large-eddy simulation (LES) based on a one-equation subgrid-scale model to investigate the flow field and pollutant dispersion characteristics inside urban street canyons. Unstable thermal stratification ...
Helton, Donald McLean
2002-01-01T23:59:59.000Z
The premise of the work presented here is to use a common analytical tool, Computational Fluid Dynamics (CFD), along with a prevalent turbulence model, Large Eddy Simulation (LES), to study the flow past rectangular cylinders. In an attempt to use...
Investigation of two-fluid methods for Large Eddy Simulation of spray combustion in Gas Turbines
Investigation of two-fluid methods for Large Eddy Simulation of spray combustion in Gas Turbines the EL method well suited for gas turbine computations, but RANS with the EE approach may also be found
Nesting large-eddy simulations within mesoscale simulations for wind energy applications
Lundquist, J K; Mirocha, J D; Chow, F K; Kosovic, B; Lundquist, K A
2008-09-08T23:59:59.000Z
With increasing demand for more accurate atmospheric simulations for wind turbine micrositing, for operational wind power forecasting, and for more reliable turbine design, simulations of atmospheric flow with resolution of tens of meters or higher are required. These time-dependent large-eddy simulations (LES), which resolve individual atmospheric eddies on length scales smaller than turbine blades and account for complex terrain, are possible with a range of commercial and open-source software, including the Weather Research and Forecasting (WRF) model. In addition to 'local' sources of turbulence within an LES domain, changing weather conditions outside the domain can also affect flow, suggesting that a mesoscale model provide boundary conditions to the large-eddy simulations. Nesting a large-eddy simulation within a mesoscale model requires nuanced representations of turbulence. Our group has improved the Weather and Research Forecasting model's (WRF) LES capability by implementing the Nonlinear Backscatter and Anisotropy (NBA) subfilter stress model following Kosovic (1997) and an explicit filtering and reconstruction technique to compute the Resolvable Subfilter-Scale (RSFS) stresses (following Chow et al, 2005). We have also implemented an immersed boundary method (IBM) in WRF to accommodate complex terrain. These new models improve WRF's LES capabilities over complex terrain and in stable atmospheric conditions. We demonstrate approaches to nesting LES within a mesoscale simulation for farms of wind turbines in hilly regions. Results are sensitive to the nesting method, indicating that care must be taken to provide appropriate boundary conditions, and to allow adequate spin-up of turbulence in the LES domain.
Chen, Qingyan "Yan"
simulation Yi Jiang and Qingyan Chen* Building Technology Program Massachusetts Institute of Technology 77 direction on cross natural ventilation in building from large eddy simulation," Building and Environment, 37 in many industrial applications. To simulate natural ventilation in buildings, however, RANS modeling has
Large-eddy Simulation of Realistic Gas Turbine Combustors , & Apte, S. V.
Apte, Sourabh V.
Large-eddy Simulation of Realistic Gas Turbine Combustors Moin, P. , & Apte, S. V. Center models and the numerical scheme is performed in canonical and complex combustor geometries. Finally, a multi-scale, multi-physics, turbulent reacting flow simulation in a real gas-turbine combustor
Assessment of combustion noise in a premixed swirled combustor via Large-Eddy Simulation
Nicoud, Franck
Assessment of combustion noise in a premixed swirled combustor via Large-Eddy Simulation Camilo F noise is conducted by both direct (LES) and hybrid computations in a premixed swirled combustor. Some5] as well as to more complex cases such as gas turbine combustors [6]. Computational techniques
Assessment of combustion noise in a premixed swirled combustor via Large-eddy simulation
Boyer, Edmond
Assessment of combustion noise in a premixed swirled combustor via Large-eddy simulation Camilo F direct (LES) and hybrid computations in a premixed swirled combustor. Some comparisons of the sound, 4, 5] as well as to more complex cases such as gas turbine combustors. [6] Corresponding author. Ph
Large Eddy Simulation Analysis of Flow Field Inside a High-g Combustor
Raman, Venkat
Large Eddy Simulation Analysis of Flow Field Inside a High-g Combustor C. Heye , C. Lietz , J-compact combustors (UCC) are a technology for reducing the size of combustors. In these combustors the fuel and air results exhibit significant entrainment of fuel into recirculation zones inside the combustor, however
Paris-Sud XI, Université de
Computing combustion noise by combining Large Eddy Simulations with analytical models +++++ Presented by Ignacio Duran Abstract Two mechanisms control combustion noise generation as shown by Marble. A method to calculate combustion-generated noise has been implemented in a tool called CHORUS. The method
Wind Energy-Related Atmospheric Boundary Layer Large-Eddy Simulation Using OpenFOAM: Preprint
Churchfield, M.J.; Vijayakumar, G.; Brasseur, J.G.; Moriarty, P.J.
2010-08-01T23:59:59.000Z
This paper develops and evaluates the performance of a large-eddy simulation (LES) solver in computing the atmospheric boundary layer (ABL) over flat terrain under a variety of stability conditions, ranging from shear driven (neutral stratification) to moderately convective (unstable stratification).
Large Eddy Simulation of Supersonic Combustion using Direct Quadrature Method of Moments
Raman, Venkat
. Supersonic combustion involves the interaction of complex gas-phase chemical reactions in a compressible flowLarge Eddy Simulation of Supersonic Combustion using Direct Quadrature Method of Moments Pratik modeling problem. In supersonic combustion, typical closures based on conserved scalar approaches cannot
Thole, Karen A.
Elsevier Inc. All rights reserved. Keywords: Duct flow; Ribbed channels; LES 1. Introduction In an effortExperimental validation of large eddy simulations of flow and heat transfer in a stationary ribbed Abstract Accurate prediction of ribbed duct flow and heat transfer is of importance to the gas turbine
Massively-Parallel Spectral Element Large Eddy Simulation of a Ring-Type Gas Turbine Combustor
Camp, Joshua Lane
2012-07-16T23:59:59.000Z
The average and fluctuating components in a model ring-type gas turbine combustor are characterized using a Large Eddy Simulation at a Reynolds number of 11,000, based on the bulk velocity and the mean channel height. A spatial filter is applied...
Numerical Investigation of a Transverse Jet in a Supersonic Crossflow using Large Eddy Simulation
Paris-Sud XI, Université de
Numerical Investigation of a Transverse Jet in a Supersonic Crossflow using Large Eddy Simulation injected fuel jets in hot supersonic crossflows. This paper describes the numerical algorithm being used into a supersonic crossflow computed on a coarse mesh. These results are discussed and similarity
Conjugate Heat Transfer with Large Eddy Simulation for Gas Turbine Components.
Nicoud, Franck
Conjugate Heat Transfer with Large Eddy Simulation for Gas Turbine Components. Florent Duchaine constraint for GT (gas turbines). Most existing CHT tools are developped for chained, steady phenomena. A film-cooled turbine vane is then studied. Thermal conduction in the blade implies lower wall
Large-eddy Simulation of the Nighttime Stable Atmospheric Boundary Layer
Zhou, Bowen
2012-01-01T23:59:59.000Z
eddy Simulation of Wind-turbine Wakes: Evaluation of Turbineperformed LES of wind-turbine wakes in neutrally stratified
Examination of steam generator turbulence by large eddy simulation
Bagwell, Ted Glyn
1989-01-01T23:59:59.000Z
phenomenon in which the vortex shedding frequency is equal to the acoustic frequency. This is primarily a problem in gas heat exchangers. This work is a continuation of work started by the Electrical Power Research Institute (EPRI), wherein the LES.... The two ongoing computer simulations are in the k- c modeling (ATHOS) (EPRI 1988a; EPRI 1988e) and the LES modeling (GUST) (EPRI 1988f; EPRI 1988e; Chilukuri et al. 1987). Both of these codes have been used to calculate the flow in both the model D-4...
Uranga Cabrera, Alejandra (Uranga)
2011-01-01T23:59:59.000Z
The present work predicts the formation of laminar separation bubbles at low Reynolds numbers and the related transition to turbulence. In addition to being one of the first Implicit Large Eddy Simulation studies using a ...
Broader source: Energy.gov [DOE]
Presentation given by Sandia National Laboratories at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about large eddy...
Large-eddy simulations of isolated disc galaxies with thermal and turbulent feedback
Braun, Harald; Niemeyer, Jens C; Almgren, Ann S
2014-01-01T23:59:59.000Z
We present a subgrid-scale model for the Multi-phase Interstellar medium, Star formation, and Turbulence (MIST) and explore its behaviour in high-resolution large-eddy simulations of isolated disc galaxies. MIST follows the evolution of a clumpy cold and a diffuse warm component of the gas within a volume element which exchange mass and energy via various cooling, heating and mixing processes. The star formation rate is dynamically computed from the state of the gas in the cold phase. An important feature of MIST is the treatment of unresolved turbulence in the two phases and its interaction with star formation and feedback by supernovae. This makes MIST a particularly suitable model for the interstellar medium in galaxy simulations. We carried out a suite of simulations varying fundamental parameters of our feedback implementation. Several observational properties of galactic star formation are reproduced in our simulations, such as an average star formation efficiency ~1%, a typical velocity dispersion arou...
to simulate events such as frontal passages through a wind plant and their effect on turbine power production-eddy simulation model designed to predict the performance of large wind plants with a higher degree of accuracy larger, but the power production of these large plants has, in some cases, been lower than initially
Large Eddy Simulation studies of the effects of alignment and wind farm length
Stevens, Richard J A M; Meneveau, Charles
2014-01-01T23:59:59.000Z
Large eddy simulations of wind farms are performed to study the effects of wind turbine row alignment with respect to the incoming flow direction. Various wind farms with fixed stream-wise spacing (7.85 rotor diameters) and varying lateral displacements and span-wise turbine spacings are considered, for a fixed inflow direction. Simulations show that, contrary to common belief, a perfectly staggered (checker-board) configuration does not necessarily give the highest average power output. Instead, the highest mean wind farm power output is found to depend on several factors, the most important one being the alignment that leads to minimization of wake effects from turbines in several upstream rows. This alignment typically occurs at significantly smaller angles than those corresponding to perfect staggering. The observed trends have implications for wind farm designs, especially in sites with a well-defined prevailing wind direction.
Temporal structure of aggregate power fluctuations in large-eddy simulations of extended wind-farms
Stevens, Richard J A M
2014-01-01T23:59:59.000Z
Fluctuations represent a major challenge for the incorporation of electric power from large wind-farms into power grids. Wind farm power output fluctuates strongly in time, over various time scales. Understanding these fluctuations, especially their spatio-temporal characteristics, is particularly important for the design of backup power systems that must be readily available in conjunction with wind-farms. In this work we analyze the power fluctuations associated with the wind-input variability at scales between minutes to several hours, using large eddy simulations (LES) of extended wind-parks, interacting with the atmospheric boundary layer. LES studies enable careful control of parameters and availability of wind-velocities simultaneously across the entire wind-farm. The present study focuses on neutral atmospheric conditions and flat terrain, using actuator-disk representations of the individual wind-turbines. We consider power from various aggregates of wind-turbines such as the total average power sign...
Chen, Qingyan "Yan"
1 Using Large Eddy Simulation to Study Airflows in and around Buildings Yi Jiang, Ph.D. Mingde Su-scale models of large eddy simulation (LES) to study airflows in and around buildings. They are the Smagorinsky, studies of airflow around a building often use wind tunnels that could simulate wind conditions. Notable
Large-Eddy Simulations of Zero-Net-Mass-Flux Jet Based Separation Control in a Canonical Separated
Mittal, Rajat
Large-Eddy Simulations of Zero-Net-Mass-Flux Jet Based Separation Control in a Canonical Separated by Mittal et al1 for investigating active separation control using zero-net-mass-flux jets. Large. Zero-net-mass-flux forcing of the separated flow at the superharmonics of this baseline lock
Creech, Angus; Maguire, A Eoghan
2014-01-01T23:59:59.000Z
We present here a computational fluid dynamics (CFD) simulation of Lillgrund offshore wind farm, which is located in the {\\O}resund Strait between Sweden and Denmark. The simulation combines a dynamic representation of wind turbines embedded within a Large-Eddy Simulation CFD solver, and uses hr-adaptive meshing to increase or decrease mesh resolution where required. This allows the resolution of both large scale flow structures around the wind farm, and local flow conditions at individual turbines; consequently, the response of each turbine to local conditions can be modelled, as well as the resulting evolution of the turbine wakes. This paper provides a detailed description of the turbine model which simulates interactions between the wind, turbine rotors, and turbine generators by calculating the forces on the rotor, the body forces on the air, and instantaneous power output. This model was used to investigate a selection of key wind speeds and directions, investigating cases where a row of turbines would ...
Stevens, Richard J A M; Meneveau, Charles
2014-01-01T23:59:59.000Z
In order to enable simulations of developing wind turbine array boundary layers with highly realistic inflow conditions a concurrent precursor method for Large Eddy Simulations is proposed. In this method we consider two domains simultaneously, i.e. in one domain a turbulent Atmospheric Boundary Layer (ABL) without wind turbines is simulated in order to generate the turbulent inflow conditions for a second domain in which the wind turbines are placed. The benefit of this approach is that a) it avoids the need for large databases in which the turbulent inflow conditions are stored and the correspondingly slow I/O operations and b) we are sure that the simulations are not negatively affected by statically swept fixed inflow fields or synthetic fields lacking the proper ABL coherent structures. Sample applications are presented, in which, in agreement with field data a strong decrease of the power output of downstream wind-turbines with respect to the first row of wind-turbines is observed for perfectly aligned ...
Large Eddy Simulation of the Diurnal Cycle in Southeast Pacific Stratocumulus
Caldwell, P; Bretherton, C
2008-03-03T23:59:59.000Z
This paper describes a series of 6 day large eddy simulations of a deep, sometimes drizzling stratocumulus-topped boundary layer based on forcings from the East Pacific Investigation of Climate (EPIC) 2001 field campaign. The base simulation was found to reproduce the observed mean boundary layer properties quite well. The diurnal cycle of liquid water path was also well captured, although good agreement appears to result partially from compensating errors in the diurnal cycles of cloud base and cloud top due to overentrainment around midday. At other times of the day, entrainment is found to be proportional to the vertically-integrated buoyancy flux. Model stratification matches observations well; turbulence profiles suggest that the boundary layer is always at least somewhat decoupled. Model drizzle appears to be too sensitive to liquid water path and subcloud evaporation appears to be too weak. Removing the diurnal cycle of subsidence had little effect on simulated cloud albedo. Simulations with changed droplet concentration and drizzle susceptibility showed large liquid water path differences at night, but differences were quite small at midday. Droplet concentration also had a significant impact on entrainment, primarily through droplet sedimentation feedback rather than through drizzle processes.
Sen, Baris Ali; Menon, Suresh [School of Aerospace Engineering, Georgia Institute of Technology, 270 Ferst Drive, Atlanta, GA 30332-0150 (United States); Hawkes, Evatt R. [School of Photovoltaic and Renewable Energy Engineering, The University of New South Wales, NSW 2052 (Australia); School of Mechanical and Manufacturing Engineering, The University of New South Wales, NSW 2052 (Australia)
2010-03-15T23:59:59.000Z
Large eddy simulation (LES) of a non-premixed, temporally evolving, syngas/air flame is performed with special emphasis on speeding-up the sub-grid chemistry computations using an artificial neural networks (ANN) approach. The numerical setup for the LES is identical to a previous direct numerical simulation (DNS) study, which reported considerable local extinction and reignition physics, and hence, offers a challenging test case. The chemical kinetics modeling with ANN is based on a recent approach, and replaces the stiff ODE solver (DI) to predict the species reaction rates in the subgrid linear eddy mixing (LEM) model based LES (LEMLES). In order to provide a comprehensive evaluation of the current approach, additional information on conditional statistics of some of the key species and temperature are extracted from the previous DNS study and are compared with the LEMLES using ANN (ANN-LEMLES, hereafter). The results show that the current approach can detect the correct extinction and reignition physics with reasonable accuracy compared to the DNS. The syngas flame structure and the scalar dissipation rate statistics obtained by the current ANN-LEMLES are provided to further probe the flame physics. It is observed that, in contrast to H{sub 2}, CO exhibits a smooth variation within the region enclosed by the stoichiometric mixture fraction. The probability density functions (PDFs) of the scalar dissipation rates calculated based on the mixture fraction and CO demonstrate that the mean value of the PDF is insensitive to extinction and reignition. However, this is not the case for the scalar dissipation rate calculated by the OH mass fraction. Overall, ANN provides considerable computational speed-up and memory saving compared to DI, and can be used to investigate turbulent flames in a computationally affordable manner. (author)
Congrs Franais de Mcanique Grenoble, 27-31 aot 2007 Large Eddy Simulation and experimentation in an
Paris-Sud XI, Université de
between the rotor and the stator have been attributed to the effects of the radial convective transport France Abstract: Comparisons between Large Eddy Simulation (LES) and velocity measurements have been mesures de vitesse par anémométrie laser Doppler à deux composantes. Le code LES est basé sur une méthode
Large-eddy simulations of turbulent flow for grid-to-rod fretting in nuclear reactors
Bakosi, J; Lowrie, R B; Pritchett-Sheats, L A; Nourgaliev, R R
2013-01-01T23:59:59.000Z
The grid-to-rod fretting (GTRF) problem in pressurized water reactors is a flow-induced vibration problem that results in wear and failure of the fuel rods in nuclear assemblies. In order to understand the fluid dynamics of GTRF and to build an archival database of turbulence statistics for various configurations, implicit large-eddy simulations of time-dependent single-phase turbulent flow have been performed in 3x3 and 5x5 rod bundles with a single grid spacer. To assess the computational mesh and resolution requirements, a method for quantitative assessment of unstructured meshes with no-slip walls is described. The calculations have been carried out using Hydra-TH, a thermal-hydraulics code developed at Los Alamos for the Consortium for Advanced Simulation of Light water reactors, a United States Department of Energy Innovation Hub. Hydra-TH uses a second-order implicit incremental projection method to solve the single-phase incompressible Navier-Stokes equations. The simulations explicitly resolve the la...
Large-eddy simulation of turbulent cavitating flow in a micro channel
Egerer, Christian P., E-mail: christian.egerer@aer.mw.tum.de; Hickel, Stefan; Schmidt, Steffen J.; Adams, Nikolaus A. [Institute of Aerodynamics and Fluid Mechanics, Technische Universität München, Boltzmannstr. 15, 85748 Garching bei München (Germany)
2014-08-15T23:59:59.000Z
Large-eddy simulations (LES) of cavitating flow of a Diesel-fuel-like fluid in a generic throttle geometry are presented. Two-phase regions are modeled by a parameter-free thermodynamic equilibrium mixture model, and compressibility of the liquid and the liquid-vapor mixture is taken into account. The Adaptive Local Deconvolution Method (ALDM), adapted for cavitating flows, is employed for discretizing the convective terms of the Navier-Stokes equations for the homogeneous mixture. ALDM is a finite-volume-based implicit LES approach that merges physically motivated turbulence modeling and numerical discretization. Validation of the numerical method is performed for a cavitating turbulent mixing layer. Comparisons with experimental data of the throttle flow at two different operating conditions are presented. The LES with the employed cavitation modeling predicts relevant flow and cavitation features accurately within the uncertainty range of the experiment. The turbulence structure of the flow is further analyzed with an emphasis on the interaction between cavitation and coherent motion, and on the statistically averaged-flow evolution.
Chen, Qingyan "Yan"
save energy consumed by the heating, ventilating, and air- conditioning systems in a building1 Natural Ventilation in Buildings: Measurement in a Wind Tunnel and Numerical Simulation@purdue.edu Abstract Natural ventilation in buildings can create a comfortable and healthy indoor environment, and can
A framework for the evaluation of turbulence closures used in mesoscale ocean large-eddy simulations
Graham, Jonathan Pietarila
2012-01-01T23:59:59.000Z
We present a methodology to determine the best turbulence closure for an eddy-permitting ocean model: measurement of the error-landscape of the closure's subgrid spectral transfers and flux. Using a high-resolution benchmark, we compare each closure's model of energy and enstrophy transfer to the actual transfer observed in the benchmark run. The error-landscape norms enable us to both make objective comparisons between the closures and to optimize each closure's free parameter for a fair comparison. We apply this method to 6 different closures for forced-dissipative simulations of the barotropic vorticity equation on a f-plane (2D Navier-Stokes equation). The hyper-viscous closure most closely reproduces the enstrophy cascade especially at larger scales due to the concentration of its dissipative effects to the very smallest scales. The viscous and Leith closures perform nearly as well especially at smaller scales where all three models were dissipative. The Smagorinsky closure dissipates enstrophy at the wr...
Churchfield, M. J.; Michalakes, J.; Vanderwende, B.; Lee, S.; Sprague, M. A.; Lundquist, J. K.; Moriarty, P. J.
2013-10-01T23:59:59.000Z
Wind plant aerodynamics are directly affected by the microscale weather, which is directly influenced by the mesoscale weather. Microscale weather refers to processes that occur within the atmospheric boundary layer with the largest scales being a few hundred meters to a few kilometers depending on the atmospheric stability of the boundary layer. Mesoscale weather refers to large weather patterns, such as weather fronts, with the largest scales being hundreds of kilometers wide. Sometimes microscale simulations that capture mesoscale-driven variations (changes in wind speed and direction over time or across the spatial extent of a wind plant) are important in wind plant analysis. In this paper, we present our preliminary work in coupling a mesoscale weather model with a microscale atmospheric large-eddy simulation model. The coupling is one-way beginning with the weather model and ending with a computational fluid dynamics solver using the weather model in coarse large-eddy simulation mode as an intermediary. We simulate one hour of daytime moderately convective microscale development driven by the mesoscale data, which are applied as initial and boundary conditions to the microscale domain, at a site in Iowa. We analyze the time and distance necessary for the smallest resolvable microscales to develop.
Churchfield, M. J.; Li, Y.; Moriarty, P. J.
2012-07-01T23:59:59.000Z
This paper presents our initial work in performing large-eddy simulations of tidal turbine array flows. First, a horizontally-periodic precursor simulation is performed to create turbulent flow data. Then that data is used as inflow into a tidal turbine array two rows deep and infinitely wide. The turbines are modeled using rotating actuator lines, and the finite-volume method is used to solve the governing equations. In studying the wakes created by the turbines, we observed that the vertical shear of the inflow combined with wake rotation causes lateral wake asymmetry. Also, various turbine configurations are simulated, and the total power production relative to isolated turbines is examined. Staggering consecutive rows of turbines in the simulated configurations allows the greatest efficiency using the least downstream row spacing. Counter-rotating consecutive downstream turbines in a non-staggered array shows a small benefit. This work has identified areas for improvement, such as the use of a larger precursor domain to better capture elongated turbulent structures, the inclusion of salinity and temperature equations to account for density stratification and its effect on turbulence, improved wall shear stress modelling, and the examination of more array configurations.
Churchfield, M. J.; Li, Y.; Moriarty, P. J.
2011-07-01T23:59:59.000Z
This paper presents our initial work in performing large-eddy simulations of tidal turbine array flows. First, a horizontally-periodic precursor simulation is performed to create turbulent flow data. Then that data is used to determine the inflow into a tidal turbine array two rows deep and infinitely wide. The turbines are modeled using rotating actuator lines, and the finite-volume method is used to solve the governing equations. In studying the wakes created by the turbines, we observed that the vertical shear of the inflow combined with wake rotation causes lateral wake asymmetry. Also, various turbine configurations are simulated, and the total power production relative to isolated turbines is examined. Staggering consecutive rows of turbines in the simulated configurations allows the greatest efficiency using the least downstream row spacing. Counter-rotating consecutive downstream turbines in a non-staggered array shows a small benefit. This work has identified areas for improvement, such as the use of a larger precursor domain to better capture elongated turbulent structures, the inclusion of salinity and temperature equations to account for density stratification and its effect on turbulence, improved wall shear stress modeling, and the examination of more array configurations.
Visualization and analysis of eddies in a global ocean simulation
Williams, Sean J [Los Alamos National Laboratory; Hecht, Matthew W [Los Alamos National Laboratory; Petersen, Mark [Los Alamos National Laboratory; Strelitz, Richard [Los Alamos National Laboratory; Maltrud, Mathew E [Los Alamos National Laboratory; Ahrens, James P [Los Alamos National Laboratory; Hlawitschka, Mario [UC DAVIS; Hamann, Bernd [UC DAVIS
2010-10-15T23:59:59.000Z
Eddies at a scale of approximately one hundred kilometers have been shown to be surprisingly important to understanding large-scale transport of heat and nutrients in the ocean. Due to difficulties in observing the ocean directly, the behavior of eddies below the surface is not very well understood. To fill this gap, we employ a high-resolution simulation of the ocean developed at Los Alamos National Laboratory. Using large-scale parallel visualization and analysis tools, we produce three-dimensional images of ocean eddies, and also generate a census of eddy distribution and shape averaged over multiple simulation time steps, resulting in a world map of eddy characteristics. As expected from observational studies, our census reveals a higher concentration of eddies at the mid-latitudes than the equator. Our analysis further shows that mid-latitude eddies are thicker, within a range of 1000-2000m, while equatorial eddies are less than 100m thick.
Attinger, Daniel
in e.g. nuclear power plants. In the present work, the mixing of a hot and a cold fluid streamLarge-eddy simulations of structure effects of an upstream elbow main pipe on hot and cold fluids Fuel Injection Equipment Stock Co., Ltd., Beijing 100166, China c Department of Mechanical Engineering
Yue, Qing; Kahn, Brian; Xiao, Heng; Schreier, Mathias; Fetzer, E. J.; Teixeira, J.; Suselj, Kay
2013-08-16T23:59:59.000Z
Cloud top entrainment instability (CTEI) is a hypothesized positive feedback between entrainment mixing and evaporative cooling near the cloud top. Previous theoretical and numerical modeling studies have shown that the persistence or breakup of marine boundary layer (MBL) clouds may be sensitive to the CTEI parameter. Collocated thermodynamic profile and cloud observations obtained from the Atmospheric Infrared Sounder (AIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS) instruments are used to quantify the relationship between the CTEI parameter and the cloud-topped MBL transition from stratocumulus to trade cumulus in the northeastern Pacific Ocean. Results derived from AIRS and MODIS are compared with numerical results from the UCLA large eddy simulation (LES) model for both well-mixed and decoupled MBLs. The satellite and model results both demonstrate a clear correlation between the CTEI parameter and MBL cloud fraction. Despite fundamental differences between LES steady state results and the instantaneous snapshot type of observations from satellites, significant correlations for both the instantaneous pixel-scale observations and the long-term averaged spatial patterns between the CTEI parameter and MBL cloud fraction are found from the satellite observations and are consistent with LES results. This suggests the potential of using AIRS and MODIS to quantify global and temporal characteristics of the cloud-topped MBL transition.
Paris-Sud XI, Université de
the temperature and pressure levels reached in the combustor, and therefore the engine efficiency. Numerical simulations of the thermal interaction between fluid flows and solids offer new design paths to diminish converge to steady thermal states. There are two basic approaches to solve Conjugate Heat Transfer (CHT
and is coupled with an actuator line model to simulate the effects of the rotating wind turbine blades. A control that is capable of resolving wind turbine blades as rotat- ing actuator lines (not fixed disks) and does not rely by the spacing between wind turbines (along and across the prevailing wind direction) and by their alignment
Complex Effects in Large Eddy Simulation Limassol, September 20-24,2005
generation, gas turbines have gained an increasing role over the years. New emission regulations and growing SIMULATIONS OF MULTIBURNER CONFIGURATIONS IN INDUSTRIAL GAS TURBINES G. Staffelbach , L. Y. M. Gicquel and T. A single burner periodic sector and a triple burner sector of an annular combustion chamber of a gas
Francis J. Robinson; Kwing L. Chan
2000-11-21T23:59:59.000Z
We present results of two simulations of the convection zone, obtained by solving the full hydrodynamic equations in a section of a spherical shell. The first simulation has cylindrical rotation contours (parallel to the rotation axis) and a strong meridional circulation, which traverses the entire depth. The second simulation has isorotation contours about mid-way between cylinders and cones, and a weak meridional circulation, concentrated in the uppermost part of the shell. We show that the solar differential rotation is directly related to a latitudinal entropy gradient, which pervades into the deep layers of the convection zone. We also offer an explanation of the angular velocity shear found at low latitudes near the top. A non-zero correlation between radial and zonal velocity fluctuations produces a significant Reynolds stress in that region. This constitutes a net transport of angular momentum inwards, which causes a slight modification of the overall structure of the differential rotation near the top. In essence, the {\\it thermodynamics controls the dynamics through the Taylor-Proudman momentum balance}. The Reynolds stresses only become significant in the surface layers, where they generate a weak meridional circulation and an angular velocity `bump'.
Churchfield, M. J.; Moriarty, P. J.; Hao, Y.; Lackner, M. A.; Barthelmie, R.; Lundquist, J.; Oxley, G. S.
2014-12-01T23:59:59.000Z
The focus of this work is the comparison of the dynamic wake meandering model and large-eddy simulation with field data from the Egmond aan Zee offshore wind plant composed of 36 3-MW turbines. The field data includes meteorological mast measurements, SCADA information from all turbines, and strain-gauge data from two turbines. The dynamic wake meandering model and large-eddy simulation are means of computing unsteady wind plant aerodynamics, including the important unsteady meandering of wakes as they convect downstream and interact with other turbines and wakes. Both of these models are coupled to a turbine model such that power and mechanical loads of each turbine in the wind plant are computed. We are interested in how accurately different types of waking (e.g., direct versus partial waking), can be modeled, and how background turbulence level affects these loads. We show that both the dynamic wake meandering model and large-eddy simulation appear to underpredict power and overpredict fatigue loads because of wake effects, but it is unclear that they are really in error. This discrepancy may be caused by wind-direction uncertainty in the field data, which tends to make wake effects appear less pronounced.
Large eddy simulation of soot formation in a turbulent non-premixed jet flame
El-Asrag, Hossam [Center For Turbulence Research, Stanford, CA 94305 (United States); Menon, Suresh [School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)
2009-02-15T23:59:59.000Z
A recently developed subgrid model for soot dynamics [H. El-Asrag, T. Lu, C.K. Law, S. Menon, Combust. Flame 150 (2007) 108-126] is used to study the soot formation in a non-premixed turbulent flame. The model allows coupling between reaction, diffusion and soot (including soot diffusion and thermophoretic forces) processes in the subgrid domain without requiring ad hoc filtering or model parameter adjustments. The combined model includes the entire process, from the initial phase, when the soot nucleus diameter is much smaller than the mean free path, to the final phase, after coagulation and aggregation, where it can be considered in the continuum regime. A relatively detailed but reduced kinetics for ethylene-air is used to simulate an experimentally studied non-premixed ethylene/air jet diffusion flame. Acetylene is used as a soot precursor species. The soot volume fraction order of magnitude, the location of its maxima, and the soot particle size distribution are all captured reasonably. Along the centerline, an initial region dominated by nucleation and surface growth is established followed by an oxidation region. The diffusion effect is found to be most important in the nucleation regime, while the thermophoretic forces become more influential downstream of the potential core in the oxidation zone. The particle size distribution shows a log-normal distribution in the nucleation region, and a more Gaussian like distribution further downstream. Limitations of the current approach and possible solution strategies are also discussed. (author)
Sliding Interfaces for Eddy Current Simulations
Hiptmair, Ralf
Sliding Interfaces for Eddy Current Simulations Raffael Casagrande Master Thesis Supervisor: Prof. Dr. Ralf Hiptmair ZÃ¼rich, April 2013 #12;Contents Contents i 1. Introduction 1 2. Eddy Current-formulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.4. The eddy current problem in a moving, solid body . . . . . . . . . . . . . 9 3. Discontinuous
Singer, M; Mirocha, J; Lundquist, J; Cleve, J
2010-03-03T23:59:59.000Z
Flow dynamics in large wind projects are influenced by the turbines located within. The turbine wakes, regions characterized by lower wind speeds and higher levels of turbulence than the surrounding free stream flow, can extend several rotor diameters downstream, and may meander and widen with increasing distance from the turbine. Turbine wakes can also reduce the power generated by downstream turbines and accelerate fatigue and damage to turbine components. An improved understanding of wake formation and transport within wind parks is essential for maximizing power output and increasing turbine lifespan. Moreover, the influence of wakes from large wind projects on neighboring wind farms, agricultural activities, and local climate are all areas of concern that can likewise be addressed by wake modeling. This work describes the formulation and application of an actuator disk model for studying flow dynamics of both individual turbines and arrays of turbines within wind projects. The actuator disk model is implemented in the Weather Research and Forecasting (WRF) model, which is an open-source atmospheric simulation code applicable to a wide range of scales, from mesoscale to large-eddy simulation. Preliminary results demonstrate the applicability of the actuator disk model within WRF to a moderately high-resolution large-eddy simulation study of a small array of turbines.
Smith, P.J.; Eddings, E.G.; Ring, T.; Thornock, J.; Draper, T.; Isaac, B.; Rezeai, D.; Toth, P.; Wu, Y.; Kelly, K.
2014-08-01T23:59:59.000Z
The objective of this task is to produce predictive capability with quantified uncertainty bounds for the heat flux in commercial-scale, tangentially fired, oxy-coal boilers. Validation data came from the Alstom Boiler Simulation Facility (BSF) for tangentially fired, oxy-coal operation. This task brings together experimental data collected under Alstom’s DOE project for measuring oxy-firing performance parameters in the BSF with this University of Utah project for large eddy simulation (LES) and validation/uncertainty quantification (V/UQ). The Utah work includes V/UQ with measurements in the single-burner facility where advanced strategies for O2 injection can be more easily controlled and data more easily obtained. Highlights of the work include: • Simulations of Alstom’s 15 megawatt (MW) BSF, exploring the uncertainty in thermal boundary conditions. A V/UQ analysis showed consistency between experimental results and simulation results, identifying uncertainty bounds on the quantities of interest for this system (Subtask 9.1) • A simulation study of the University of Utah’s oxy-fuel combustor (OFC) focused on heat flux (Subtask 9.2). A V/UQ analysis was used to show consistency between experimental and simulation results. • Measurement of heat flux and temperature with new optical diagnostic techniques and comparison with conventional measurements (Subtask 9.3). Various optical diagnostics systems were created to provide experimental data to the simulation team. The final configuration utilized a mid-wave infrared (MWIR) camera to measure heat flux and temperature, which was synchronized with a high-speed, visible camera to utilize two-color pyrometry to measure temperature and soot concentration. • Collection of heat flux and temperature measurements in the University of Utah’s OFC for use is subtasks 9.2 and 9.3 (Subtask 9.4). Several replicates were carried to better assess the experimental error. Experiments were specifically designed for the generation of high-fidelity data from a turbulent oxy-coal flame for the validation of oxy-coal simulation models. Experiments were also conducted on the OFC to determine heat flux profiles using advanced strategies for O2 injection. This is important when considering retrofit of advanced O2 injection in retrofit configurations.
Draxl, C.; Churchfield, M.; Mirocha, J.; Lee, S.; Lundquist, J.; Michalakes, J.; Moriarty, P.; Purkayastha, A.; Sprague, M.; Vanderwende, B.
2014-06-01T23:59:59.000Z
Wind plant aerodynamics are influenced by a combination of microscale and mesoscale phenomena. Incorporating mesoscale atmospheric forcing (e.g., diurnal cycles and frontal passages) into wind plant simulations can lead to a more accurate representation of microscale flows, aerodynamics, and wind turbine/plant performance. Our goal is to couple a numerical weather prediction model that can represent mesoscale flow [specifically the Weather Research and Forecasting model] with a microscale LES model (OpenFOAM) that can predict microscale turbulence and wake losses.
Denmark and Sweden and compared results with more than a year's worth of plant data.The simulated power at least 50% wastepaper, including 10% post consumer waste. NREL Develops Simulations forWind Plant Power-eddy simulation of an entire wind plant. Researchers at the National Renewable Energy Laboratory's (NREL) National
Bauer, Georg; Gamnitzer, Peter [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany)] [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany); Gravemeier, Volker, E-mail: vgravem@lnm.mw.tum.de [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany) [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany); Emmy Noether Research Group “Computational Multiscale Methods for Turbulent Combustion”, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany); Wall, Wolfgang A. [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany)] [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany)
2013-10-15T23:59:59.000Z
Highlights: •We present a computational method for coupled multi-ion transport in turbulent flow. •The underlying formulation is a variational multiscale finite element method. •It is combined with the isogeometric concept for electrochemical systems. •Coupled multi-ion transport in fully turbulent Taylor–Couette flow is simulated. •This example is an important model problem for rotating cylinder electrodes. -- Abstract: Electrochemical processes, such as electroplating of large items in galvanic baths, are often coupled to turbulent flow. In this study, we propose an isogeometric residual-based variational multiscale finite element method for multi-ion transport in dilute electrolyte solutions under turbulent flow conditions. In other words, this means that the concepts of isogeometric discretization and variational multiscale methods are successfully combined for developing a method capable of simulating the challenging problem of coupled multi-ion transport in turbulent flow. We present a comprehensive three-dimensional computational method taking into account, among others, coupled convection–diffusion-migration equations subject to an electroneutrality constraint in combination with phenomenological electrode-kinetics modeling. The electrochemical subproblem is one-way coupled to turbulent incompressible flow via convection. Ionic mass transfer in turbulent Taylor–Couette flow is investigated, representing an important model problem for rotating-cylinder-electrode configurations. Multi-ion transport as considered here is an example for mass transport at high Schmidt number (Sc=1389). An isogeometric discretization is especially advantageous for the present problem, since (i) curved boundaries can be represented exactly, and (ii) it has been proven to provide very accurate solutions for flow quantities when being applied in combination with residual-based variational multiscale modeling. We demonstrate that the method is robust and provides results which are in good agreement with direct numerical simulation results as well as empirical mass-transfer correlations reported in literature.
Sliding Interfaces for Eddy Current Simulations Raffael Casagrande
Hiptmair, Ralf
Sliding Interfaces for Eddy Current Simulations Raffael Casagrande Supervisor: Prof. Dr. Ralf Interfaces for Eddy Current April 17th, 2013 1 / 25 #12;Outline 1 Introduction Motivation 2 Deriving the eddy current model Maxwell's Equations in a moving frame The eddy current model in a moving frame 3
Gregory L. Eyink
1996-02-19T23:59:59.000Z
We establish and discuss {\\em a priori} estimates on subgrid stress and subgrid flux for filtering schemes used in the turbulence modelling method of Large-Eddy Simulation (LES). Our estimates are derived as rigorous consequences of the exact subgrid stress formulae from Navier-Stokes equations under realistic conditions for inertial-range velocity fields, those conjectured in the Parisi-Frisch ``multifractal model.'' The estimates are shown to be an expression of ``local energy cascade,'' i.e. the dominance of local wavevector triads in the energy transfer. We prove that for nearly any reasonable filter function the LES method defines an energy flux in which local triads dominate in individual realizations, due to cancellation of distant triadic contributions by detailed conservation. A somewhat similar observation of Leslie and Quarini on graded filters in the EDQNM closure is shown to be unrelated to the cancellation we establish in Navier-Stokes solutions. The sharp Fourier cutoff filter is one example which does not satisfy the modest conditions of our proof and, in fact, we show that with that filter the energy transfer in individual realizations at arbitrarily high Reynolds number will be dominated by nonlocal, convective sweeping.
Multiscale eddy simulation for moist atmospheric convection: Preliminary investigation
Stechmann, Samuel N., E-mail: stechmann@wisc.edu [Department of Mathematics, University of Wisconsin-Madison (United States); Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison (United States)
2014-08-15T23:59:59.000Z
A multiscale computational framework is designed for simulating atmospheric convection and clouds. In this multiscale framework, large eddy simulation (LES) is used to model the coarse scales of 100 m and larger, and a stochastic, one-dimensional turbulence (ODT) model is used to represent the fine scales of 100 m and smaller. Coupled and evolving together, these two components provide a multiscale eddy simulation (MES). Through its fine-scale turbulence and moist thermodynamics, MES allows coarse grid cells to be partially cloudy and to encompass cloudy–clear air mixing on scales down to 1 m; in contrast, in typical LES such fine-scale processes are not represented or are parameterized using bulk deterministic closures. To illustrate MES and investigate its multiscale dynamics, a shallow cumulus cloud field is simulated. The fine-scale variability is seen to take a plausible form, with partially cloudy grid cells prominent near cloud edges and cloud top. From earlier theoretical work, this mixing of cloudy and clear air is believed to have an important impact on buoyancy. However, contrary to expectations based on earlier theoretical studies, the mean statistics of the bulk cloud field are essentially the same in MES and LES; possible reasons for this are discussed, including possible limitations in the present formulation of MES. One difference between LES and MES is seen in the coarse-scale turbulent kinetic energy, which appears to grow slowly in time due to incoherent stochastic fluctuations in the buoyancy. This and other considerations suggest the need for some type of spatial and/or temporal filtering to attenuate undersampling of the stochastic fine-scale processes.
Coupled Mesoscale-Large-Eddy Modeling of Realistic Stable Boundary Layer Turbulence
Wang, Yao; Manuel, Lance
2013-01-01T23:59:59.000Z
Site-specific flow and turbulence information are needed for various practical applications, ranging from aerodynamic/aeroelastic modeling for wind turbine design to optical diffraction calculations. Even though highly desirable, collecting on-site meteorological measurements can be an expensive, time-consuming, and sometimes a challenging task. In this work, we propose a coupled mesoscale-large-eddy modeling framework to synthetically generate site-specific flow and turbulence data. The workhorses behind our framework are a state-of-the-art, open-source atmospheric model called the Weather Research and Forecasting (WRF) model and a tuning-free large-eddy simulation (LES) model. Using this coupled framework, we simulate a nighttime stable boundary layer (SBL) case from the well-known CASES-99 field campaign. One of the unique aspects of this work is the usage of a diverse range of observations for characterization and validation. The coupled models reproduce certain characteristics of observed low-level jets....
Eddy current NDE performance demonstrations using simulation tools
Maurice, L. [EDF - CEIDRE, 2 rue Ampere, 93206 Saint-Denis Cedex 1 (France); Costan, V.; Guillot, E.; Thomas, P. [EDF - R and D, THEMIS, 1, avenue du General de Gaulle, 92141 Clamart (France)
2013-01-25T23:59:59.000Z
To carry out performance demonstrations of the Eddy-Current NDE processes applied on French nuclear power plants, EDF studies the possibility of using simulation tools as an alternative to measurements on steam generator tube mocks-up. This paper focuses on the strategy led by EDF to assess and use code{sub C}armel3D and Civa, on the case of Eddy-Current NDE on wears problem which may appear in the U-shape region of steam generator tubes due to the rubbing of anti-vibration bars.
Fast Solver for Large Scale Eddy Current Non-Destructive Evaluation Problems
Fast Solver for Large Scale Eddy Current Non-Destructive Evaluation Problems Naiguang Lei Advisor: Lalita Udpa Thursday, July 31st, 2014 9:00-11:00am, EB2219 Abstract Eddy current testing plays a very, an alternating magnetic field source generates induced currents, called eddy currents, in an electrically
Nicoud, Franck
turbine blades conditions the temperature and pres- sure levels reached in the combustor, and therefore the engine effi- ciency. Numerical simulations of the thermal interaction between fluid flows and solids to efficiently converge to steady thermal states. There are two basic approaches to solve Conjugate Heat Trans
Adaptive Detached Eddy Simulation of a High Lift Wing with Active...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
and slat support). Adaptive Detached Eddy Simulation of a High Lift Wing with Active Flow Control PI Name: Kenneth Jansen PI Email: jansenke@colorado.edu Institution:...
Simulation for the assessment of wall thinning using eddy current method
Cheng, W.; Komura, I. [NDE Center, Japan Power Engineering and Inspection Corporation, Yokohama 230-0044 (Japan)
2011-06-23T23:59:59.000Z
A pipe with protective cladding and insulation was simplified to a four-layered structure when the diameter of a pipe is large enough, and analytical solutions for sinusoidal and pulsed wave excitation were derived. Simulation implemented by using the analytical solutions showed that sinusoidal excitation is not appropriate for the monitoring of inner thinning, while pulsed eddy current method can be used to measure wall-thickness regardless of inner or outer thinning by using the decay rate of log(Bz) as a particular parameter to evaluate wall thickness.
Lundquist, Katherine Ann
2010-01-01T23:59:59.000Z
large-eddy simulations within mesoscale simulations for windEddy Simulation of a Mesoscale Convective Internal Boundary185, 1957. Pielke, R. , Mesoscale Meteorological Modeling,
Study on eddy current losses and shielding measures in large power transformers
Chen Yongbin; Yu Hainian [Shenyang Transformer Research Inst. (China)] [Shenyang Transformer Research Inst. (China); Yang Junyou; Tang Renyuan [Shenyang Polytechnic Univ. (China)] [Shenyang Polytechnic Univ. (China)
1994-09-01T23:59:59.000Z
The improved T-{Omega} method is applied to the computation of the three dimensional eddy current field in a 360MVA/500kV large power transformer, the structure of which is complicated. The different cases of tank wall with magnetic shunt, aluminum screen or without any shield are analyzed. The relations between eddy current losses and the materials, structure and size of the tank shield are presented. Compared with a parallel magnetic shunt arrangement, the vertical magnetic shunt reduces stray losses by 63.8%. The optimal thickness or the vertical magnetic shunt Is 10mm. The magnetic shunt should be spread over 0.5mm at both ends of windings in the 360MVA/500kV large power transformer.
Marusic, Ivan
Large-scale eddies and their role in entrainment in turbulent jets and wakes Jimmy Philip and Ivan jets and wakes Jimmy Philipa) and Ivan Marusicb) Department of Mechanical Engineering, University
Hagos, Samson M.; Leung, Lai-Yung R.; Gustafson, William I.; Singh, Balwinder
2014-02-28T23:59:59.000Z
A multi-scale moisture budget analysis is used to identify the mechanisms responsible for the sensitivity of the water cycle to spatial resolution using idealized regional aquaplanet simulations. In the higher resolution simulations, moisture transport by eddies fluxes dry the boundary layer enhancing evaporation and precipitation. This effect of eddies, which is underestimated by the physics parameterizations in the low-resolution simulations, is found to be responsible for the sensitivity of the water cycle both directly, and through its upscale effect, on the mean circulation. Correlations among moisture transport by eddies at adjacent ranges of scales provides the potential for reducing this sensitivity by representing the unresolved eddies by their marginally resolved counterparts.
Large eddy simulation of turbulence within heat exchangers
Pruitt, John Myron
1992-01-01T23:59:59.000Z
by the Electric Power Research Institute (EPRI), and continued within the Nuclear Engineering Department of Texas A&M University. Previous investigation has predicted the turbulent characteristics within the waterbox region of the Westinghouse D-4 steam... generator. Further investigation has included single and multiple tube configurations using coarse meshes. EPRI has supported this effort with many experimental investigations designed to provide data for comparison and validation of the technique...
Large Eddy Simulation (LES) Applied to Advanced Engine Combustion...
Broader source: Energy.gov (indexed) [DOE]
over broad operating ranges) - Requirements for efficient and routine use of high-performance computing (HPC), development of both predictive and affordable models for advanced...
Large Eddy Simulation (LES) Applied to Advanced Engine Combustion...
Broader source: Energy.gov (indexed) [DOE]
Flow Research - 8353 Combustion Chemistry - 8362 Engine Combustion - 8365 ThermalFluid Science and Engineering * Professor W. Anderson, Purdue * Professor J. -Y. Chen, UC...
Large Eddy Simulation (LES) Applied to Advanced Engine Combustion...
Broader source: Energy.gov (indexed) [DOE]
3 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting ace007oefelein2013o.pdf More Documents & Publications...
Large Eddy Simulation (LES) Applied to Advanced Engine Combustion Research
Broader source: Energy.gov [DOE]
2013 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting
Large Eddy Simulations of Jet Flow Interactions Within Rod Bundles
Salpeter, Nathaniel O.
2010-07-14T23:59:59.000Z
5,603,819 4 2.00mm 4,439,612 5 3.00mm 4,237,281 19 a) 0.65mm Cell Size b) 0.75mm Cell Size b) 0.9mm Cell Size c) 1.2mm Cell Size d) 2mm Cell Size e) 3mm Cell Size... ................................................................................................. 16 2.3. Grid Sensitivity Study Results and Discussion .............................................. 23 2.4. Analysis Methods ........................................................................................... 31 3. RESULTS...
Study of natural ventilation in buildings with large eddy simulation
Jiang, Yi, 1972-
2002-01-01T23:59:59.000Z
With the discovery of many economic, environmental, and health problems in sealed and mechanically ventilated buildings, the concept of natural ventilation has been revived. "Buildings that breathe" have become more and ...
Vehicle Technologies Office Merit Review 2015: Large Eddy Simulation (LES)
Broader source: Energy.gov (indexed) [DOE]
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group current C3EDepartmentDepartment ofConstruction || DepartmentTesting
LARGE EDDY SIMULATION OF NATURAL AND MIXED CONVECTION AIRFLOW INDOORS
Chen, Qingyan "Yan"
coordinate Greek symbols : Thermal expansion coefficient t : Time step : Filter size : Kinematic viscocity convection, such as winter heating by a baseboard heater; forced convection, such as free cooling in shoulder
Large Eddy Simulation (LES) Applied to Advanced Engine Combustion Research
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport(FactDepartment ofLetter Report:40PM toLEDControl Concept |EnergyLandscapingThe|
Large Eddy Simulations of Combustor Liner Flows | Argonne Leadership
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 - -/e),,sand CERNLand andComputing Facility
Prediction of Small-Scale Cavitation in a High Speed Flow Over an Open Cavity Using Large Eddy
Apte, Sourabh V.
Prediction of Small-Scale Cavitation in a High Speed Flow Over an Open Cavity Using Large Eddy- gether with the cavitation models predict that inception occurs near the trailing edge similar in cavitation. 1 INTRODUCTION The problem of cavitation has been widely studied owing to its influence
Sandia Energy - Simulating Turbine-Turbine Interaction
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
of wind-turbine wakes within a turbulent atmospheric boundary layer using a large eddy simulation (LES) method. Current and ongoing work aims to leverage the simulation...
Large-scale simulations of reionization
Kohler, Katharina; /JILA, Boulder /Fermilab; Gnedin, Nickolay Y.; /Fermilab; Hamilton, Andrew J.S.; /JILA, Boulder
2005-11-01T23:59:59.000Z
We use cosmological simulations to explore the large-scale effects of reionization. Since reionization is a process that involves a large dynamic range--from galaxies to rare bright quasars--we need to be able to cover a significant volume of the universe in our simulation without losing the important small scale effects from galaxies. Here we have taken an approach that uses clumping factors derived from small scale simulations to approximate the radiative transfer on the sub-cell scales. Using this technique, we can cover a simulation size up to 1280h{sup -1} Mpc with 10h{sup -1} Mpc cells. This allows us to construct synthetic spectra of quasars similar to observed spectra of SDSS quasars at high redshifts and compare them to the observational data. These spectra can then be analyzed for HII region sizes, the presence of the Gunn-Peterson trough, and the Lyman-{alpha} forest.
advanced analytical simulation: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
in Drizzling Stratiform Clouds Based on Large-Eddy Simulations University of Kansas - KU ScholarWorks Summary: Cloud microphysical parameterizations and retrievals...
Raman, Venkat
while the small-scale motions are modeled using sub-filter models. Since gas-turbine relevant combustion providing better input for the combustion models. Developing LES-based combustion models for stationary gas) based approach is used here to deal with the complexities of gas turbine combustion. In the PDF approach
White, D
2009-04-30T23:59:59.000Z
Simulation of three-dimensional transient eddy current problems is important to numerous applications. The Finite Element Method (FEM) has proven be to be powerful numerical technique for solving the Partial Differential Equations (PDE) describing eddy currents. In order to solve the PDE, boundary conditions must be provided, and in many applications the boundary conditions are not known explicitly but can be provided by a Resistor-Inductor-Capacitor (RLC) circuit model. The emphasis of this paper is on an efficient and exact coupling of the RLC network equations with the FEM equations. The coupling is based on an exact linear algebra identity known as the Sherman-Morrison-Woodbury (SMW) formula. One advantage of this approach is that the FEM matrices are not modified. This is important if a fast 'black-box' solver is available for the FEM matrices, these solvers typically require that the matrices have certain mathematical properties and these properties are not modified by the SMW approach. A second advantage is that the SMW approach is valid for an arbitrary number of independent external circuits.
NREL Develops Simulations for Wind Plant Power and Turbine Loads (Fact Sheet)
Not Available
2012-04-01T23:59:59.000Z
NREL researchers are the first to use a high-performance computing tool for a large-eddy simulation of an entire wind plant.
Large-scale Intelligent Transporation Systems simulation
Ewing, T.; Canfield, T.; Hannebutte, U.; Levine, D.; Tentner, A.
1995-06-01T23:59:59.000Z
A prototype computer system has been developed which defines a high-level architecture for a large-scale, comprehensive, scalable simulation of an Intelligent Transportation System (ITS) capable of running on massively parallel computers and distributed (networked) computer systems. The prototype includes the modelling of instrumented ``smart`` vehicles with in-vehicle navigation units capable of optimal route planning and Traffic Management Centers (TMC). The TMC has probe vehicle tracking capabilities (display position and attributes of instrumented vehicles), and can provide 2-way interaction with traffic to provide advisories and link times. Both the in-vehicle navigation module and the TMC feature detailed graphical user interfaces to support human-factors studies. The prototype has been developed on a distributed system of networked UNIX computers but is designed to run on ANL`s IBM SP-X parallel computer system for large scale problems. A novel feature of our design is that vehicles will be represented by autonomus computer processes, each with a behavior model which performs independent route selection and reacts to external traffic events much like real vehicles. With this approach, one will be able to take advantage of emerging massively parallel processor (MPP) systems.
Large-Eddy Simulation of the Bachalo-Johnson Flow, with Shock...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
proposals for carbon capture and sequestration also involve supersonic flows in the compressors. This project will focus on the upper surface of a transport aircraft wing,...
Large Eddy Simulation of laser ignition and compressible reacting flow in a rocket-like
Paris-Sud XI, Université de
combustion devices. The technical needs for internal-combustion (IC) engines and aircraft combustors have in a rocket engine is a critical problem for combustion cham- ber design. Delayed ignition may lead to high without failure. The combustion initiation in rocket engines is usually based on pyrotechnic devices
Large eddy simulation of supersonic combustion with application to scramjet engines
Cocks, Peter
2011-07-12T23:59:59.000Z
.4.1 Desirable Properties . . . . . . . . . . . . . . . . . . . . . 64 4.4.1.1 Monotonicity . . . . . . . . . . . . . . . . . . . . 65 4.4.1.2 High Order of Accuracy . . . . . . . . . . . . . . 65 4.4.2 Discretisation Techniques... [105] (a) Detail of noz- zle and combustor (b) Detail of combustor entrance and injector geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 7.2 Hydrogen mass fraction distribution on the combustor centreline . 185 7.3 Planes...
Turbulence prediction in two- and three-dimensional bundle flows using Large Eddy Simulation
Ibrahim, Wael Abdul-Hamid
1994-01-01T23:59:59.000Z
using both models. The results are then compared with the experimental data obtained previously from the experiment conducted at the Electrical Power Research Institute (EPRI NP-5540, May 1988b). For the purpose of completeness, LES is further used...
Large Eddy Simulation (LES) Applied to LTC/Diesel/Hydrogen Engine...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
10 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C. ace007oefelein2010o.pdf More Documents &...
Large-Eddy Simulation of Pulverized Coal Jet Flame -Effect of Oxygen Concentration on NOx formation
Muto, Masaya; Watanabe, Hiroaki; Kurose, Ryoichi; Komori, Satoru; Balusamy, Saravanan; Hochgreb, Simone
2015-01-01T23:59:59.000Z
than those by using other fossil fuels [1]. It is therefore important to develop clean coal technology for pulverized coal fired power plants, in order to control such emissions and to reduce the environmental impact. Regarding the reduction... of environmental impact of CO2, carbon capture and sequestration (CCS) is expected as a key technology, and it is believed that oxy-fuel pulverized coal combus- tion, in which gas mixture of oxygen (O2) and CO2 are used instead of air as oxidizer, has advantages...
Large-Eddy Simulations of a Drizzling, Stratocumulus-Topped Marine Boundary
Stevens, Bjorn
and Technology Yokahama, Japan Markus D. Petters Department of Atmospheric Science Colorado State University, Colorado Kozo Nakamura Frontier Research Center for Global Change Japan Agency for Marine-Earth Science on the global heat budget (Klein and Hartmann 1993). Evidence suggests they constitute a leading
Pierce, Stephen
Oceanographic Institution, Woods Hole, MA, USA. 4 Naval Air Systems Command, Patuxent River, MD, USA
Large-Eddy Simulation of a Supersonic Inlet-Isolator Heeseok Koo
Raman, Venkat
in a dual-mode scramjet engine that provides stable compressed flow to the combustor. However function in weighted essentially nonoscillatory scheme cp = heat capacity at constant pressure e = nonchemical, sensible energy, m2 =s2 et = nonchemical total energy, m2 =s2 F = flux G = filtering kernel h
Large-Eddy Simulation of a Supersonic Inlet-Isolator Heeseok Koo1
Raman, Venkat
The University of Texas at Austin, Austin, Tx, 78712 The isolator is an important flow section in a dual in hyperviscosity model cp = heat capacity at constant pressure cj = weighting function in WENO scheme e = non-chemical, sensible energy, m2 /s2 et = non-chemical total energy, m2 /s2 F = flux h = isolator height IP
Large-eddy simulation of lean hydrogenemethane turbulent premixed flames in the methane-
GÃ¼lder, Ã?mer L.
-based to hydrogen-based economy are still under discussion and the implementation of the hydrogen- based economy methane flame in the methane- dominated regime. Copyright Âª 2014, Hydrogen Energy Publications, LLC appear to be a promising option to synergistically pave the way toward pure hydrogen- based combustion
Turbulence prediction using the large eddy simulation method in staggered and inlined bundles
Barsamian, Hagop Raffi
1994-01-01T23:59:59.000Z
and not the cause of the instability (France and Hopkins, 1994). This process has been studied by Song and Yuan (1990) for both primary and secondary vortices with relative success, as well as Polak and Weaver (1994) in triangular tube arrays. The forces...
ON THE EULERIAN LARGE EDDY SIMULATION OF DISPERSE PHASE FLOWS: AN ASYMPTOTIC PRESERVING SCHEME FOR
Paris-Sud XI, UniversitÃ© de
. These constraints are: 1/as the resulting sound speed is inversely proportional to the Stokes number, it is highly on the accurate description of both the continuous carrier phase, gaseous or liquid, and the discrete particulate
Massively Parallel Spectral Element Large Eddy Simulation of a Turbulent Channel Using Wall Models
Rabau, Joshua I
2013-05-01T23:59:59.000Z
Wall-bounded turbulent flows are prevalent in engineering and industrial applications. Walls greatly affect turbulent characteristics in many ways including production and propagation of turbulent stresses. While computational fluid dynamics can...
Kewlani, Gaurav
2014-01-01T23:59:59.000Z
High efficiency, low emissions and stable operation over a wide range of conditions are some of the key requirements of modem-day combustors. To achieve these objectives, lean premixed flames are generally preferred as ...
LARGE EDDY SIMULATION FOR TURBULENT MHD FLOWS A. LABOVSKY AND C. TRENCHEA
Trenchea, Catalin
problems such as plasma confinement, controlled thermonuclear fusion, liquid-metal cooling of nuclear
Numerical errors in the computation of subfilter scalar variance in large eddy simulations
Raman, Venkat
Mechanics, The University of Texas at Austin, Austin, Texas 78712, USA 2 Center for Turbulence Research of specific model forms. Like other subfilter quantities, such as kinetic energy, subfilter variance can-rule manipulations used to derive convection, diffusion, and production terms associated with the square
Raman, Venkat
Crossflow Sin Hyen Kim , Optimulation, LLC., Austin, Texas, 78731, USA Pratik Donde , Venkat Raman crossflow (JISC) provide e cient mixing and flame stabilization in su- personic combustion. A LES-DQMOM based comprehensive methodology was developed and calculated sonic jet in Mach 2.0 crossflow
Large-Eddy Simulation of Pulverized Coal Jet Flame -Effect of Oxygen Concentration on NOx formation
Muto, Masaya; Watanabe, Hiroaki; Kurose, Ryoichi; Komori, Satoru; Balusamy, Saravanan; Hochgreb, Simone
2015-01-01T23:59:59.000Z
than those by using other fossil fuels [1]. It is therefore important to develop clean coal technology for pulverized coal fired power plants, in order to control such emissions and to reduce the environmental impact. Regarding the reduction...
Kogan, Yefim L.; Kogan, Zena N.; Mechem, David B.
2009-08-01T23:59:59.000Z
Cloud microphysical parameterizations and retrievals rely heavily on knowledge of the shape of drop size distributions (DSDs). Many investigations assume that DSDs in the entire or partial drop size range may be approximated ...
Large-eddy Simulation of the Nighttime Stable Atmospheric Boundary Layer
Zhou, Bowen
2012-01-01T23:59:59.000Z
coordinate and (b) wind and potential temperature at the up-coordinate and (b) wind and potential temperature at the up-Mean profiles of wind and potential temperature, turbulent
Evaluating Subgrid-Scale Models for Large-Eddy Simulation of Turbulent Katabatic Flow
Fedorovich, Evgeni
of LES for reproducing stably-stratified turbulent boundary layers [2]. Under stably-stratified conditions, the characteristic length scale of the small-scale turbulent motions decrease, placing a larger analytically for a laminar slope flow in a stably- stratified environment. The Prandtl solution
Large Eddy Simulation (LES) Applied to LTC/Diesel/Hydrogen Engine
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport(FactDepartment ofLetter Report:40PM toLEDControl Concept
Large Eddy Simulation (LES) Applied to LTC/Diesel/Hydrogen Engine
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport(FactDepartment ofLetter Report:40PM toLEDControl ConceptCombustion Research |
Large Eddy Simulation (LES) Applied to Low-Temperature and Diesel Engine
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport(FactDepartment ofLetter Report:40PM toLEDControl ConceptCombustion Research
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 - -/e),,sand CERNLand and
Large-Eddy Simulation for Green Energy and Propulsion Systems | Argonne
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 - -/e),,sand CERNLandLargefor High
Bailey-Kellogg, Chris
Intelligent Simulation Tools for Mining Large Scienti#12;c Data Sets 1 Intelligent Simulation Tools for Mining Large Scienti#12;c Data Sets Feng ZHAO Xerox Palo Alto Research Center 3333 Coyote Hill Road, Palo. Keywords Intelligent simulation, Scienti#12;c data mining, Qualitative reasoning, Reasoning about physical
van Zanten, Margreet C; Stevens, Bjorn; Nuijens, Louise; Siebesma, A Pier; Ackerman, A. S.; Burnet, F.; Cheng, A.; Couvreux, F.; Jiang, H.; Khairoutdinov, M.; Kogan, Yefim L.; Lewellen, D. C.; Mechem, David B.
2011-06-28T23:59:59.000Z
Twelve large-eddy simulations, with a wide range of microphysical representations, are compared to each other and to independent measurements. The measurements and the initial and forcing data for the simulations are taken ...
Effects of Sea-Salt Aerosols on Precipitation in Simulations of Shallow Cumulus
Kogan, Yefim L.; Mechem, David B.; Choi, Kityan
2012-02-01T23:59:59.000Z
A suite of large-eddy simulations with size-resolving microphysical processes was performed in order to assess effects of sea-salt aerosols on precipitation process in trade cumulus. Simulations based on observations from ...
Large-scale simulations of complex physical systems
Belic, A. [Scientific Computing Laboratory, Institute of Physics, Pregrevica 118, 11080 Belgrade (Serbia and Montenegro)
2007-04-23T23:59:59.000Z
Scientific computing has become a tool as vital as experimentation and theory for dealing with scientific challenges of the twenty-first century. Large scale simulations and modelling serve as heuristic tools in a broad problem-solving process. High-performance computing facilities make possible the first step in this process - a view of new and previously inaccessible domains in science and the building up of intuition regarding the new phenomenology. The final goal of this process is to translate this newly found intuition into better algorithms and new analytical results.In this presentation we give an outline of the research themes pursued at the Scientific Computing Laboratory of the Institute of Physics in Belgrade regarding large-scale simulations of complex classical and quantum physical systems, and present recent results obtained in the large-scale simulations of granular materials and path integrals.
Not Available
2011-02-01T23:59:59.000Z
Researchers at the National Renewable Energy Laboratory (NREL) develop a high-fidelity large-eddy simulation model designed to predict the performance of large wind plants with a higher degree of accuracy than current models.
An Evaluation of the Network Simulators in Large-Scale Distributed Simulations
Ciraci, Selim; Akyol, Bora A.
2011-11-13T23:59:59.000Z
This is a survey paper about the state-of-the-art in large-scale network simulation. Networks for the smart grids are characterized by millions of sensor nodes exchanging information about the status of the grid. This information exchange must be realized reliably and efficiently due to the mission critical nature of the power grid. Hence, the applications and the network protocols developed for the smart grid need go through rigorous testing and analysis before deployment. Developers usually do not have access to such a large-scale network that can be used as a controlled test-bed; therefore, network simulation becomes an essential tool for testing. Network simulation is a well studied problem in the literature and there are various widely used network simulators. These simulators can be adopted for testing applications and protocols of the smart grid. Due to the scale of these networks, parallel/distributed simulations need to be conducted. Even though most network simulators support distributed simulations, generating a large-scale network model to simulate can still be a cumbersome task. In this survey, we describe a selection of commonly used network simulators and evaluate them with respect to the following features that can aid users in distributed simulations of large-scale networks: transparency of setting up distributed simulation, automated topology generation, information hiding, lightweight routing protocols, network error simulation, evaluation of the network model during simulation and trace analysis tools. As a complementary result, we identify two issues with network simulators that can be addressed with runtime steering methods.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign: Potential ApplicationYu, James Cowin PNNLDeviceDiagnosis
Toward Improved Support for Loosely Coupled Large Scale Simulation Workflows
Boehm, Swen [ORNL] [ORNL; Elwasif, Wael R [ORNL] [ORNL; Naughton, III, Thomas J [ORNL; Vallee, Geoffroy R [ORNL] [ORNL
2014-01-01T23:59:59.000Z
High-performance computing (HPC) workloads are increasingly leveraging loosely coupled large scale simula- tions. Unfortunately, most large-scale HPC platforms, including Cray/ALPS environments, are designed for the execution of long-running jobs based on coarse-grained launch capabilities (e.g., one MPI rank per core on all allocated compute nodes). This assumption limits capability-class workload campaigns that require large numbers of discrete or loosely coupled simulations, and where time-to-solution is an untenable pacing issue. This paper describes the challenges related to the support of fine-grained launch capabilities that are necessary for the execution of loosely coupled large scale simulations on Cray/ALPS platforms. More precisely, we present the details of an enhanced runtime system to support this use case, and report on initial results from early testing on systems at Oak Ridge National Laboratory.
Lieb, Jason
Ambulatory Care Thurston Bowles Neurosciences MBRB Carolina Inn Paul Green Graham Davis Lib Eddie Smith Field
Technical Note Correction of Eddy-Current Distortions in Diffusion
Technical Note Correction of Eddy-Current Distortions in Diffusion Tensor Images Using the Known,2 Purpose: To correct eddy-current artifacts in diffusion ten- sor (DT) images without the need to obtain- tortions caused by eddy currents induced by large diffusion gradients. We propose a new postacquisition
Large Scale Simulation of Tor: Modelling a Global Passive Adversary
Blott, Stephen
. Implementing global passive adversary attacks on currently deployed low latency anonymous networks designs have been developed which attempt to apply mixes to low latency traffic. The most widelyLarge Scale Simulation of Tor: Modelling a Global Passive Adversary Gavin O' Gorman and Stephen
Materialized community ground models for large-scale earthquake simulation
Shewchuk, Jonathan
Materialized community ground models for large-scale earthquake simulation Steven W. Schlosser to ground motion sim- ulations, in which ground model datasets are fully materi- alized into octress stored as a service techniques in which scientific computation and storage services become more tightly intertwined. 1
The use of large plot rainfall simulation to investigate
Sorenson, Joshua Russell
2006-04-12T23:59:59.000Z
In this study, large scale rainfall simulation was used to evaluate runoff generation from canopy and intercanopy areas within an ashe juniper woodland of the Edwards Plateau. One 3 x 12 m site was established beneath the canopy of mature ashe...
SIMULATING LARGE-SCALE STRUCTURE FORMATION FOR BSI POWER SPECTRA
V. Mueller
1995-05-30T23:59:59.000Z
A double inflationary model provides perturbation spectra with enhanced power at large scales (Broken Scale Invariant perturbations -- BSI), leading to a promising scenario for the formation of cosmic structures. We describe a series of high-resolution PM simulations with a model for the thermodynamic evolution of baryons in which we are capable of identifying 'galaxy' halos with a reasonable mass spectrum and following the genesis of large and super-large scale structures. The power spectra and correlation functions of 'galaxies' are compared with reconstructed power spectra of the CfA catalogue and the correlation functions of the Las Campanas Deep Redshift Survey.
Tidal Residual Eddies and their Effect on Water Exchange in Puget Sound
Yang, Zhaoqing; Wang, Taiping
2013-08-30T23:59:59.000Z
Tidal residual eddies are one of the important hydrodynamic features in tidally dominant estuaries and coastal bays, and they could have significant effects on water exchange in a tidal system. This paper presents a modeling study of tides and tidal residual eddies in Puget Sound, a tidally dominant fjord-like estuary in the Pacific Northwest coast, using a three-dimensional finite-volume coastal ocean model. Mechanisms of vorticity generation and asymmetric distribution patterns around an island/headland were analyzed using the dynamic vorticity transfer approach and numerical experiments. Model results of Puget Sound show that a number of large twin tidal residual eddies exist in the Admiralty Inlet because of the presence of major headlands in the inlet. Simulated residual vorticities near the major headlands indicate that the clockwise tidal residual eddy (negative vorticity) is generally stronger than the anticlockwise eddy (positive vorticity) because of the effect of Coriolis force. The effect of tidal residual eddies on water exchange in Puget Sound and its sub-basins were evaluated by simulations of dye transport. It was found that the strong transverse variability of residual currents in the Admiralty Inlet results in a dominant seaward transport along the eastern shore and a dominant landward transport along the western shore of the Inlet. A similar transport pattern in Hood Canal is caused by the presence of tidal residual eddies near the entrance of the canal. Model results show that tidal residual currents in Whidbey Basin are small in comparison to other sub-basins. A large clockwise residual circulation is formed around Vashon Island near entrance of South Sound, which can potentially constrain the water exchange between the Central Basin and South Sound.
Lilly, Jonathan
that govern the heat supply to ice shelves in the Eastern Weddell Sea. The simulations confirm the low melt
Eddy Current Model of Ball Lightning
J. D. Shelton
2011-02-07T23:59:59.000Z
Eddy Current Model of Ball Lightning Calculations show that high-energy ball lightning may consist of a ball of plasma containing a large circular electric current arising as an eddy current generated by lightning. Synthetic ball lightning might serve as a method of plasma confinement for purposes of nuclear fusion. In this paper, three articles concerning ball lightning and the related phenomenon of large ball lightning are combined to provide insight into this rarely glimpsed occurrence.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Plimpton, Steve; Thompson, Aidan; Crozier, Paul
LAMMPS (http://lammps.sandia.gov/index.html) stands for Large-scale Atomic/Molecular Massively Parallel Simulator and is a code that can be used to model atoms or, as the LAMMPS website says, as a parallel particle simulator at the atomic, meso, or continuum scale. This Sandia-based website provides a long list of animations from large simulations. These were created using different visualization packages to read LAMMPS output, and each one provides the name of the PI and a brief description of the work done or visualization package used. See also the static images produced from simulations at http://lammps.sandia.gov/pictures.html The foundation paper for LAMMPS is: S. Plimpton, Fast Parallel Algorithms for Short-Range Molecular Dynamics, J Comp Phys, 117, 1-19 (1995), but the website also lists other papers describing contributions to LAMMPS over the years.
Numerical simulation of flow distribution for pebble bed high temperature gas cooled reactors
Yesilyurt, Gokhan
2004-09-30T23:59:59.000Z
?....................................................................................26 V CFD MODELLING ...................................................................................28 V.1 Computational Fluid Dynamics (CFD) ..........................................28 V.2 The History.... Hassan The premise of the work presented here is to use a common analytical tool, Computational Fluid Dynamics (CFD), along with different turbulence models. Eddy viscosity models as well as state-of-the-art Large Eddy Simulation (LES) were...
Fast time domain simulation for large order hybrid systems
Sou, Kin Cheong, 1979-
2002-01-01T23:59:59.000Z
Simulation is an important tool for the analysis and design of complex systems. As the models become more and more complex, more powerful simulation methods are desired. As an attempt to address this problem, a simulation ...
Paris-Sud XI, Université de
A new database generation method combining maximin method and kriging prediction for eddy-current@evt.bme.hu Abstract: The accurate numerical simulation of the eddy- current testing (ECT) experiments usually requires-based adaptive methodology which yields to databases optimized to the given problem. Keywords: eddy-current
AN EFFICIENT EDDY CURRENT MODEL FOR NONLINEAR MAXWELL EQUATIONS WITH LAMINATED CONDUCTORS
Zheng, Weiying
AN EFFICIENT EDDY CURRENT MODEL FOR NONLINEAR MAXWELL EQUATIONS WITH LAMINATED CONDUCTORS XUE JIANG AND WEIYING ZHENG Abstract. In this paper, we propose a new eddy current model for the nonlinear Maxwell equations with laminated conductors. Direct simulation of three-dimensional (3D) eddy currents in grain
Interface Exchange as an Indicator for Eddy Heat Transport
Petersen, Mark R. [Los Alamos National Laboratory; Williams, Sean J. [Los Alamos National Laboratory; Hecht, Matthew W. [Los Alamos National Laboratory; Maltrud, Mathew E. [Los Alamos National Laboratory; Hamann, Bernd [U of California Davis; Patchett, John M. [Los Alamos National Laboratory; Ahrens, James P. [Los Alamos National Laboratory
2012-06-12T23:59:59.000Z
The ocean contains many large-scale, long-lived vortices, called mesoscale eddies, that are believed to have a role in the transport and redistribution of salt, heat, and nutrients throughout the ocean. Determining this role, however, has proven to be a challenge, since the mechanics of eddies are only partly understood; a standard definition for these ocean eddies does not exist and, therefore, scientifically meaningful, robust methods for eddy extraction, characterization, tracking and visualization remain a challenge. In order to shed light on the nature and potential roles of eddies, we have combined our previous research on eddy identification and tracking, and have used those approaches as the basis for analysis-driven computational experiments on the nature of eddies. Based on the resulting visualizations of eddy behavior, we have devised a new metric to characterize the transfer of water into and out of eddies across their boundary, and have developed visualization methods for this new metric to provide clues about the role eddies play in the global ocean and, potentially, climate change.
Large-eddy simulation/probability density function modeling of a non-premixed CO/H2
;applicable to practical devices such as gas turbine combustors and internal combustion engines [2 4]. In LES School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14853, USA b Combustion PDFs of compositions. Ó 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved
DeCroix, D. S. (David S.)
2002-01-01T23:59:59.000Z
In October 2000, the US Department of Energy, along with NOAA and several other government labs and universities, conducted the Vertical Transport and Mixing Experiment (VTMX) and URBAN2000 field programs in Salt Lake City, Utah (Alwine et al., 2002). The VTMX program focused on the basin-scale flow regime, where the URBAN2000 component focused on transport and dispersion in the downtown Salt Lake City area. In this paper, we will focus on a specific Intensive Operations Period, IOP-10, which occurred on October 25-26, 2000. IOP-16 was chosen because the winds in the downtown area were fairly weak and variable early in the experiment, and became more windy in the later part of the IOP. The local conditions were influenced by a shortwave ridge, and were cloudy, with a weak and very shallow surface inversion, and light mean southerly flow over the area. An inert tracer gas, SF6, was released downtown Salt Lake City for a duration of one hour at three separate times on 26 October 2000, 01:00-02:00, 03:00-04:00, and 05:00-06:00 MDT. This paper will focus on the first release time, from 01:00-02:00 MDT.
Mirocha, Jeffrey D.; Kosovi?, Branko
2010-01-01T23:59:59.000Z
to the surface of the snow/ice pack is often prevented byheat ?ux from the snow/ice pack interior, which constrainsover the Arctic Ocean snow/ice pack during clear-sky, winter
Chow, Fotini Katopodes
reflect off grid refinement interfaces, specifically on the outflow boundary from a fine to a coarse grid reflection off grid refinement interfaces by forcing the filter-resolved scale on a fine grid to equal
Zhang, Huangwei; Garmory, Andrew; Cavaliere, Davide E.; Mastorakos, Epaminondas
2014-06-25T23:59:59.000Z
of around 100,000 polyhedral cells and is refined in the fuel jet and flame regions, thereby leading to 100-200 LES cells within one CMC cell there. This CMC mesh refinement is expected to be useful here because fine local CMC resolution can better... . In CMC, h=0 corresponds to air and h=1 to pure fuel, both at 298 K. The fully burning steady solutions with 10 50 sN ?? from a 0D-CMC calculation are used to initialize all the CMC cells. Inert mixing solutions are injected in the air and fuel inlets...
Oberai, Assad A [Rensselaer Polytechnic Instistute
2013-07-16T23:59:59.000Z
In the report we present a summary of the new models and algorithms developed by the PI and the students supported by this grant. These developments are described in detail in ten peer-reviewed journal articles that acknowledge support from this grant.
Sun, Long
2011-01-01T23:59:59.000Z
When the convection heat transfer model is well validated,models, convection heat transfer model is often over-and a convection heat transfer model with local accuracy is
Sun, Long
2011-01-01T23:59:59.000Z
losses of a flat-plate collector, Solar Energy 35, 15–19.from outer cover of solar collectors, Renew. Energ. 10 (4)
Jagannathan, Shriram
2012-02-14T23:59:59.000Z
. The vortex shed from the bubble, convects downstream and interacts with the trailing edge vortices increasing the turbulence intensity. On the suction side, dominant hairpin structures near the transitional and turbulent flow regime are observed...
Mirocha, Jeffrey D.; Kosovi?, Branko
2010-01-01T23:59:59.000Z
Mean pro?les of potential temperature, wind speed, verticalsection. 4.1 Potential Temperature and Wind Speed Pro?lesequilibrium LES potential temperature and wind speed pro?les
Large-Scale Atomistic Simulations of Material Failure
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Abraham, Farid [IBM Almaden Research; Duchaineau, Mark [LLNL; Wirth, Brian [LLNL; Heidelberg,; Seager, Mark [LLNL; De La Rubia, Diaz [LLNL
These simulations from 2000 examine the supersonic propagation of cracks and the formation of complex junction structures in metals. Eight simulations concerning brittle fracture, ductile failure, and shockless compression are available.
Computer Energy Modeling Techniques for Simulation Large Scale Correctional Institutes in Texas
Heneghan, T.; Haberl, J. S.; Saman, N.; Bou-Saada, T. E.
1996-01-01T23:59:59.000Z
Building energy simulation programs have undergone an increase in use for evaluating energy consumption and energy conservation retrofits in buildings. Utilization of computer simulation programs for large facilities with multiple buildings, however...
Schmidt, W; Niemeyer, J C
2006-01-01T23:59:59.000Z
We present a one-equation subgrid scale model that evolves the turbulence energy corresponding to unresolved velocity fluctuations in large eddy simulations. The model is derived in the context of the Germano consistent decomposition of the hydrodynamical equations. The eddy-viscosity closure for the rate of energy transfer from resolved toward subgrid scales is localised by means of a dynamical procedure for the computation of the closure parameter. Therefore, the subgrid scale model applies to arbitrary flow geometry and evolution. For the treatment of microscopic viscous dissipation a semi-statistical approach is used, and the gradient-diffusion hypothesis is adopted for turbulent transport. A priori tests of the localised eddy-viscosity closure and the gradient-diffusion closure are made by analysing data from direct numerical simulations. As an a posteriori testing case, the large eddy simulation of thermonuclear combustion in forced isotropic turbulence is discussed. We intend the formulation of the sub...
A FINITE ELEMENT APPROACH FOR SIMULATING THE QUENCHING OF LARGE ALUMINIUM COMPRESSOR WHEELS
A FINITE ELEMENT APPROACH FOR SIMULATING THE QUENCHING OF LARGE ALUMINIUM COMPRESSOR WHEELS A FINITE ELEMENT APPROACH FOR SIMULATING THE QUENCHING OF LARGE ALUMINIUM COMPRESSOR WHEELS Dirk Büche Aluminum devices such as compressor wheels are typically heat treated in order to achieve the required
Large-Scale Molecular Dynamics Simulations for Highly Parallel Infrastructures
Pazúriková, Jana
2014-01-01T23:59:59.000Z
Computational chemistry allows researchers to experiment in sillico: by running a computer simulations of a biological or chemical processes of interest. Molecular dynamics with molecular mechanics model of interactions simulates N-body problem of atoms$-$it computes movements of atoms according to Newtonian physics and empirical descriptions of atomic electrostatic interactions. These simulations require high performance computing resources, as evaluations within each step are computationally demanding and billions of steps are needed to reach interesting timescales. Current methods decompose the spatial domain of the problem and calculate on parallel/distributed infrastructures. Even the methods with the highest strong scaling hit the limit at half a million cores: they are not able to cut the time to result if provided with more processors. At the dawn of exascale computing with massively parallel computational resources, we want to increase the level of parallelism by incorporating parallel-in-time comput...
Simulating large cosmology surveys with calibrated halo models
Lynn, Stuart
2011-11-23T23:59:59.000Z
In this thesis I present a novel method for constructing large scale mock galaxy and halo catalogues and apply this model to a number of important topics in modern cosmology. Traditionally such mocks are created through ...
Large-scale simulator for global data infrastructure optimization
Herrero-López, Sergio
2012-01-01T23:59:59.000Z
Companies depend on information systems to control their operations. During the last decade, Information Technology (IT) infrastructures have grown in scale and complexity. Any large company runs many enterprise applications ...
Real-time Monitoring of Large Scientific Simulations
Pascucci, Valerio
space-filling curves. The Lebesgue curve is also known as Z-order, Morton, .... Curve. Special case. · Simple load balancing on visualization side. · Fast slicing, isosurfacing, and volume rendering. #12;The7 B8 B13 B14 B15 B16 · Takes advantage of simulation load balancing · One Data Source per compute
Paris-Sud XI, Université de
Eddy current evaluation of air-gaps in aeronautical multilayered assemblies using multi in an aeronautical multilayered metallic assembly, by the means of the eddy current method. A behavioural multi, either for simulated or experimental data. KEYWORDS: Non-destructive evaluation, eddy currents, multi
Nabben, Reinhard
-harmonic eddy current model in two dimensions. The first criterion is the robustness with respect Expansions, Eddy- current model AMS subject classifications. 65N30, 35C20, 35J25, 41A60, 35B40, 78M30, 78M35 Introduction. For simulations of the eddy current problem with thin sheets by standard methods, like the finite
Smith, K. Shafer
Mesoscale Eddy Energy Locality in an Idealized Ocean Model IAN GROOMS, LOUIS-PHILIPPE NADEAU, AND K investigates the energy budget of mesoscale eddies in wind-driven two-layer quasigeostrophic simulations of eddy energy are ``nonlocal.'' Many mesoscale parameterizations assume that statistics of the unresolved
Induced Currents, Eddy Currents and
Tobar, Michael
Lecture 11 Induced Currents, Eddy Currents and Maxwell's Equations 1 Faraday Disk Dynamo F = q Eddy Currents We have learnt that changing magnetic fields can induce electric fields in conductors 108 ms-1 16 #12;In this lecture and the next Eddy Currents: We have covered Sect. 29
GridMate: A Portable Simulation Environment for Large-Scale Adaptive Scientific Applications
Li, Xiaolin "Andy"
GridMate: A Portable Simulation Environment for Large-Scale Adaptive Scientific Applications: parashar@caip.rutgers.edu Abstract--In this paper, we present a portable sim- ulation environment GridMate for large-scale adaptive scientific applications in multi-site Grid environments. GridMate is a discrete
Parallel domain decomposition for simulation of large-scale power grids
Mohanram, Kartik
of large-scale linear circuits such as power grids. DD techniques that use non-overlapping and overlap that with the proposed parallel DD framework, existing linear circuit simulators can be extended to handle large- scale can be solved independently in parallel using standard techniques for linear system analysis
Seasonal Modulation of Eddy Kinetic Energy and Its Formation Mechanism in the Southeast Indian Ocean
Qiu, Bo
energy and exert profound impacts on large-scale ocean circulations. Satellite altimeter ob- servations- sociations with the large-scale oceanic circulations and the climate. The global eddy kinetic energy (EKESeasonal Modulation of Eddy Kinetic Energy and Its Formation Mechanism in the Southeast Indian
LES/probability density function approach for the simulation of an ethanol spray flame
Raman, Venkat
LES/probability density function approach for the simulation of an ethanol spray flame Colin Heye a an experimental pilot-stabilized ethanol spray flame. In this particular flame, droplet evaporation occurs away: Large-eddy simulation; Probability density function; Flamelet/progress variable approach; Ethanol
Mesoscale flows in large aspect ratio simulations of turbulent compressible convection
F. Rincon; F. Lignieres; M. Rieutord
2006-11-28T23:59:59.000Z
We present the results of a very large aspect ratio (42.6) numerical simulation of fully compressible turbulent convection in a polytropic atmosphere, and focus on the properties of large-scale flows. Mesoscale patterns dominate the turbulent energy spectrum. We show that these structures, which had already been observed in Boussinesq simulations by Cattaneo et al. (2001), have a genuine convective origin and do not result directly from collective interactions of the smaller scales of the flow, even though their growth is strongly affected by nonlinear transfers. If this result is relevant to the solar photosphere, it suggests that the dominant convective mode below the Sun's surface may be at mesoscales.
Boyer, Edmond
866 IEEE TRANSACTIONS ON MAGNETICS, VOL. 44, NO. 6, JUNE 2008 Dynamical Models for Eddy Current accurate dynamical models for representing eddy currents are studied. The simulation of the relay is provided. Index Terms--AC circuit breakers (CBs), eddy currents, magnetic hysteresis, optimization methods
In-situ sampling of a large-scale particle simulation for interactive visualization and analysis
Woodring, Jonathan L [Los Alamos National Laboratory; Ahrens, James P [Los Alamos National Laboratory; Heitmann, Katrin [Los Alamos National Laboratory
2010-12-09T23:59:59.000Z
We propose storing a random sampling of data from large scale particle simulations, such as the Roadrunner Universe MC{sup 3} cosmological simulation, to be used for interactive post-analysis and visualization. Simulation data generation rates will continue to be far greater than storage bandwidth rates and other limiting technologies by many orders of magnitude. This implies that only a very small fraction of data generated by the simulation can ever be stored and subsequently post-analyzed. The limiting technology in this situation is analogous to the problem in many population surveys: there aren't enough human resources to query a large population. To cope with the lack of resources, statistical sampling techniques are used to create a representative data set of a large population. Mirroring that situation, we propose to store a simulation-time random sampling of the particle data to cope with the bOlllenecks and support interactive, exploratory post-analysis. The particle samples are immediately stored in a level-ol-detail format for post-visualization and analysis, which amortizes the cost of post-processing for interactive visualization. Additionally, we incorporate a system for recording and visualizing sample approximation error information for confidence and importance highlighting.
Simulating the Power Consumption of Large-Scale Sensor Network Applications
Simulating the Power Consumption of Large-Scale Sensor Network Applications Victor Shnayder, Mark of the most important as- pects of sensor application design: that of power consump- tion. While simple approximations of overall power usage can be derived from estimates of node duty cycle and com- munication rates
Large-scale simulations of fluctuating biological membranes Andrea Pasqua,1,a
Oster, George
in their computational demands, these approaches are still limited in the scope of fluctuations and response they can's response to a prodding nanorod. © 2010 American Institute of Physics. doi:10.1063/1.3382349 I. INTRODUCTION feasibly capture. Extending computer simulations to examine large scale behaviors such as aggregation
Simulation of large-amplitude motion of floating wind turbines using conservation of momentum
Sweetman, Bert
hull size, which would allow more compliance with the wind thrust force in the pitch directionSimulation of large-amplitude motion of floating wind turbines using conservation of momentum Lei December 2011 Editor-in-Chief: A.I. Incecik Available online 28 January 2012 Keywords: Floating wind
Simulation-based optimization of communication protocols for large-scale wireless sensor networks1
Maróti, Miklós
1 Simulation-based optimization of communication protocols for large-scale wireless sensor networks--The design of reliable, dynamic, fault-tolerant services in wireless sensor networks is a big challenge everyday life more comfortable, e.g. Intelligent Spaces [3]. These sensor networks often use distributed
Large-scale molecular dynamics simulation of magnetic properties of amorphous iron under pressure
) Enhanced refrigerant capacity and magnetic entropy flattening using a two-amorphous FeZrB(Cu) compositeLarge-scale molecular dynamics simulation of magnetic properties of amorphous iron under pressure Appl. Phys. Lett. 99, 232501 (2011) Nonlinear motion of magnetic vortex under alternating
An avenue of eddies: Quantifying the biophysical properties of mesoscale eddies in the Tasman Sea
Oke, Peter
after separating from the coast. Through a 16-year analysis of Tasman Sea eddies, we identify a region of cyclonic and anticyclonic eddies within Eddy Avenue is 23% and 16% higher respectively than the broader Tasman Sea. We find that Eddy Avenue cyclonic and anti- cyclonic eddies have more strongly differentiated
Dynamic procedure for filtered gyrokinetic simulations
Morel, P.; Banon Navarro, A.; Albrecht-Marc, M.; Carati, D. [Statistical and Plasma Physics Laboratory, Universite Libre de Bruxelles, Bruxelles 1050 (Belgium); Merz, F.; Goerler, T.; Jenko, F. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)
2012-01-15T23:59:59.000Z
Large eddy simulations (LES) of gyrokinetic plasma turbulence are investigated as interesting candidates to decrease the computational cost. A dynamic procedure is implemented in the gene code, allowing for dynamic optimization of the free parameters of the LES models (setting the amplitudes of dissipative terms). Employing such LES methods, one recovers the free energy and heat flux spectra obtained from highly resolved direct numerical simulations. Systematic comparisons are performed for different values of the temperature gradient and magnetic shear, parameters which are of prime importance in ion temperature gradient driven turbulence. Moreover, the degree of anisotropy of the problem, which can vary with parameters, can be adapted dynamically by the method that shows gyrokinetic large eddy simulation to be a serious candidate to reduce numerical cost of gyrokinetic solvers.
Turbulence Modelling and Stirring Mechanisms in the Cosmological Large-scale Structure
Iapichino, L; Niemeyer, J C; Merklein, J
2011-01-01T23:59:59.000Z
FEARLESS (Fluid mEchanics with Adaptively Refined Large Eddy SimulationS) is a numerical scheme for modelling subgrid-scale turbulence in cosmological adaptive mesh refinement simulations. In this contribution, the main features of this tool will be outlined. We discuss the application of this method to cosmological simulations of the large-scale structure. The simulations show that the production of turbulence has a different redshift dependence in the intra-cluster medium and the warm-hot intergalactic medium, caused by the distinct stirring mechanisms (mergers and shock interactions) acting in them. Some properties of the non-thermal pressure support in the two baryon phases are also described.
NV Energy Large-Scale Photovoltaic Integration Study: Intra-Hour Dispatch and AGC Simulation
Lu, Shuai; Etingov, Pavel V.; Meng, Da; Guo, Xinxin; Jin, Chunlian; Samaan, Nader A.
2013-01-02T23:59:59.000Z
The uncertainty and variability with photovoltaic (PV) generation make it very challenging to balance power system generation and load, especially under high penetration cases. Higher reserve requirements and more cycling of conventional generators are generally anticipated for large-scale PV integration. However, whether the existing generation fleet is flexible enough to handle the variations and how well the system can maintain its control performance are difficult to predict. The goal of this project is to develop a software program that can perform intra-hour dispatch and automatic generation control (AGC) simulation, by which the balancing operations of a system can be simulated to answer the questions posed above. The simulator, named Electric System Intra-Hour Operation Simulator (ESIOS), uses the NV Energy southern system as a study case, and models the system’s generator configurations, AGC functions, and operator actions to balance system generation and load. Actual dispatch of AGC generators and control performance under various PV penetration levels can be predicted by running ESIOS. With data about the load, generation, and generator characteristics, ESIOS can perform similar simulations and assess variable generation integration impacts for other systems as well. This report describes the design of the simulator and presents the study results showing the PV impacts on NV Energy real-time operations.
Low frequency eddy current benchmark study for model validation
Mooers, R. D.; Boehnlein, T. R. [University of Dayton Research Institute, Structural Integrity Division, Dayton, OH, 45469 (United States); Cherry, M. R.; Knopp, J. S. [Air Force Research Lab, NDE Division, Wright Patterson, OH 45433 (United States); Aldrin, J. C. [Computational Tools, Gurnee, IL 60031 (United States); Sabbagh, H. A. [Victor Technologies LLC, Bloomington, IN 47401 (United States)
2011-06-23T23:59:59.000Z
This paper presents results of an eddy current model validation study. Precise measurements were made using an impedance analyzer to investigate changes in impedance due to Electrical Discharge Machining (EDM) notches in aluminum plates. Each plate contained one EDM notch at an angle of 0, 10, 20, or 30 degrees from the normal of the plate surface. Measurements were made with the eddy current probe both scanning parallel and perpendicular to the notch length. The experimental response from the vertical and oblique notches will be reported and compared to results from different numerical simulation codes.
SSALMON - The Solar Simulations for the Atacama Large Millimeter Observatory Network
Wedemeyera, S; Brajsa, R; Barta, M; Hudson, H; Fleishman, G; Loukitcheva, M; Fleck, B; Kontar, E; De Pontieu, B; Tiwari, S; Kato, Y; Soler, R; Yagoubov, P; Black, J H; Antolin, P; Gunar, S; Labrosse, N; Benz, A O; Nindos, A; Steffen, M; Scullion, E; Doyle, J G; Zaqarashvili, T; Hanslmeier, A; Nakariakov, V M; Heinzel, P; Ayres, T; Karlicky, M
2015-01-01T23:59:59.000Z
The Solar Simulations for the Atacama Large Millimeter Observatory Network (SSALMON) was initiated in 2014 in connection with two ALMA development studies. The Atacama Large Millimeter/submillimeter Array (ALMA) is a powerful new tool, which can also observe the Sun at high spatial, temporal, and spectral resolution. The international SSALMONetwork aims at coordinating the further development of solar observing modes for ALMA and at promoting scientific opportunities for solar physics with particular focus on numerical simulations, which can provide important constraints for the observing modes and can aid the interpretation of future observations. The radiation detected by ALMA originates mostly in the solar chromosphere - a complex and dynamic layer between the photosphere and corona, which plays an important role in the transport of energy and matter and the heating of the outer layers of the solar atmosphere. Potential targets include active regions, prominences, quiet Sun regions, flares. Here, we give a...
Whitton, Mary C.
Daniels Hill Ackland McCaskill Paul Green Eddie Smith Alumni Center Carmichael Auditorium Center Student Dean E. Smith Student Hall Kenan Field House Bookstore Affairs Stadium Kenan Hill Williams House Forest
Eddy fluxes in baroclinic turbulence
Thompson, Andrew F.
2006-01-01T23:59:59.000Z
near-inertial energy in an eddying ocean channel model. Geo-dissipation of tidal energy in the deep ocean inferred fromfor the Southern Ocean), the rate of energy input by wind
Doyle, Martin
Excellence Center for Loudermilk Graham Memorial Daniels Hill Ackland McCaskill Paul Green Eddie Smith Alumni Carolina at Chapel Hill : 500 5000 Feet Student Life Classrooms Health Affairs Libraries Parking Decks
Energy Spectra of Quantum Turbulence: Large-scale Simulation and Modeling
Machida, Masahiko; Kano, Takuma; L'vov, Victor S; Rudenko, Oleksii; Tsubota, Makoto
2010-01-01T23:59:59.000Z
In 2048^3 simulation of quantum turbulence within the Gross-Pitaevskii equation we demonstrate that the large scale motions have a classical Kolmogorov-1941 energy spectrum E(k) ~ k^{-5/3}, followed by an energy accumulation with E(k) ~ const at 1/k about the mean intervortex distance. This behavior was predicted by the L'vov-Nazarenko-Rudenko bottleneck model [Phys.Rev.B 76, 024520 (2007)], further developed in the Letter.
Copy of Using Emulation and Simulation to Understand the Large-Scale Behavior of the Internet.
Adalsteinsson, Helgi; Armstrong, Robert C.; Chiang, Ken; Gentile, Ann C. [Sandia National Laboratories, Albuquerque, NM; Lloyd, Levi; Minnich, Ronald G.; Vanderveen, Keith; Van Randwyk, Jamie A; Rudish, Don W.
2008-10-01T23:59:59.000Z
We report on the work done in the late-start LDRDUsing Emulation and Simulation toUnderstand the Large-Scale Behavior of the Internet. We describe the creation of a researchplatform that emulates many thousands of machines to be used for the study of large-scale inter-net behavior. We describe a proof-of-concept simple attack we performed in this environment.We describe the successful capture of a Storm bot and, from the study of the bot and furtherliterature search, establish large-scale aspects we seek to understand via emulation of Storm onour research platform in possible follow-on work. Finally, we discuss possible future work.3
Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider
R. Bruce; R. W. Assmann; V. Boccone; C. Bracco; M. Brugger; M. Cauchi; F. Cerutti; D. Deboy; A. Ferrari; L. Lari; A. Marsili; A. Mereghetti; D. Mirarchi; E. Quaranta; S. Redaelli; G. Robert-Demolaize; A. Rossi; B. Salvachua; E. Skordis; C. Tambasco; G. Valentino; T. Weiler; V. Vlachoudis; D. Wollmann
2014-09-10T23:59:59.000Z
The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010--2013, the LHC was routinely storing protons at 3.5--4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An un-controlled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multi-stage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the collimation system. The studies include tracking of protons through the fields of more than 5000 magnets in the 27 km LHC ring over hundreds of revolutions, and Monte-Carlo simulations of particle-matter interactions both in collimators and machine elements being hit by escaping particles. The simulation results agree typically within a factor 2 with measurements of beam loss distributions from the previous LHC run. Considering the complex simulation, which must account for a very large number of unknown imperfections, and in view of the total losses around the ring spanning over 7 orders of magnitude, we consider this an excellent agreement. Our results give confidence in the simulation tools, which are used also for the design of future accelerators.
Large-scale simulation of methane dissociation along the West Spitzbergen Margin
Reagan, M.T.; Moridis, G.J.
2009-07-15T23:59:59.000Z
Vast quantities of methane are trapped in oceanic hydrate deposits, and there is concern that a rise in the ocean temperature will induce dissociation of these hydrate accumulations, potentially releasing large amounts of methane into the atmosphere. The recent discovery of active methane gas venting along the landward limit of the gas hydrate stability zone (GHSZ) on the shallow continental slope west of Spitsbergen could be an indication of this process, if the source of the methane can be confidently attributed to dissociating hydrates. In the first large-scale simulation study of its kind, we simulate shallow hydrate dissociation in conditions representative of the West Spitsbergen margin to test the hypothesis that the observed gas release originated from hydrates. The simulation results are consistent with this hypothesis, and are in remarkable agreement with the recently published observations. They show that shallow, low-saturation hydrate deposits, when subjected to temperature increases at the seafloor, can release significant quantities of methane, and that the releases will be localized near the landward limit of the top of the GHSZ. These results indicate the possibility that hydrate dissociation and methane release may be both a consequence and a cause of climate change.
Calculation of Eddy Currents In the CTH Vacuum Vessel and Coil Frame
A. Zolfaghari, A. Brooks, A. Michaels, J. Hanson, and G. Hartwell
2012-09-25T23:59:59.000Z
Knowledge of eddy currents in the vacuum vessel walls and nearby conducting support structures can significantly contribute to the accuracy of Magnetohydrodynamics (MHD) equilibrium reconstruction in toroidal plasmas. Moreover, the magnetic fields produced by the eddy currents could generate error fields that may give rise to islands at rational surfaces or cause field lines to become chaotic. In the Compact Toroidal Hybrid (CTH) device (R0 = 0.75 m, a = 0.29 m, B ? 0.7 T), the primary driver of the eddy currents during the plasma discharge is the changing flux of the ohmic heating transformer. Electromagnetic simulations are used to calculate eddy current paths and profile in the vacuum vessel and in the coil frame pieces with known time dependent currents in the ohmic heating coils. MAXWELL and SPARK codes were used for the Electromagnetic modeling and simulation. MAXWELL code was used for detailed 3D finite-element analysis of the eddy currents in the structures. SPARK code was used to calculate the eddy currents in the structures as modeled with shell/surface elements, with each element representing a current loop. In both cases current filaments representing the eddy currents were prepared for input into VMEC code for MHD equilibrium reconstruction of the plasma discharge. __________________________________________________
Eddy current scanning at Fermilab
Boffo, C.; Bauer, P.; Foley, M.; /Fermilab; Brinkmann, A.; /DESY; Ozelis, J.; /Jefferson Lab
2005-07-01T23:59:59.000Z
In the framework of SRF cavity development, Fermilab is creating the infrastructure needed for the characterization of the material used in the cavity fabrication. An important step in the characterization of ''as received'' niobium sheets is the eddy current scanning. Eddy current scanning is a non-destructive technique first adopted and further developed by DESY with the purpose of checking the cavity material for sub-surface defects and inclusions. Fermilab has received and further upgraded a commercial eddy current scanner previously used for the SNS project. The upgrading process included developing new filtering software. This scanner is now used daily to scan the niobium sheets for the Fermilab third harmonic and transverse deflecting cavities. This paper gives a status report on the scanning results obtained so far, including a discussion of the typology of signals being detected. We also report on the efforts to calibrate this scanner, a work conducted in collaboration with DESY.
Expert system for analyzing eddy current measurements
Levy, Arthur J. (Schenectady, NY); Oppenlander, Jane E. (Scotia, NY); Brudnoy, David M. (Albany, NY); Englund, James M. (Clifton Park, NY); Loomis, Kent C. (Clifton Park, NY)
1994-01-01T23:59:59.000Z
A method and apparatus (called DODGER) analyzes eddy current data for heat exchanger tubes or any other metallic object. DODGER uses an expert system to analyze eddy current data by reasoning with uncertainty and pattern recognition. The expert system permits DODGER to analyze eddy current data intelligently, and obviate operator uncertainty by analyzing the data in a uniform and consistent manner.
Testing of Large-Scale ICV Glasses with Hanford LAW Simulant
Hrma, Pavel R.; Kim, Dong-Sang; Vienna, John D.; Matyas, Josef; Smith, Donald E.; Schweiger, Michael J.; Yeager, John D.
2005-03-01T23:59:59.000Z
Preliminary glass compositions for immobilizing Hanford low-activity waste (LAW) by the in-container vitrification (ICV) process were initially fabricated at crucible- and engineering-scale, including simulants and actual (radioactive) LAW. Glasses were characterized for vapor hydration test (VHT) and product consistency test (PCT) responses and crystallinity (both quenched and slow-cooled samples). Selected glasses were tested for toxicity characteristic leach procedure (TCLP) responses, viscosity, and electrical conductivity. This testing showed that glasses with LAW loading of 20 mass% can be made readily and meet all product constraints by a far margin. Glasses with over 22 mass% Na2O can be made to meet all other product quality and process constraints. Large-scale testing was performed at the AMEC, Geomelt Division facility in Richland. Three tests were conducted using simulated LAW with increasing loadings of 12, 17, and 20 mass% Na2O. Glass samples were taken from the test products in a manner to represent the full expected range of product performance. These samples were characterized for composition, density, crystalline and non-crystalline phase assemblage, and durability using the VHT, PCT, and TCLP tests. The results, presented in this report, show that the AMEC ICV product with meets all waste form requirements with a large margin. These results provide strong evidence that the Hanford LAW can be successfully vitrified by the ICV technology and can meet all the constraints related to product quality. The economic feasibility of the ICV technology can be further enhanced by subsequent optimization.
Chakravarty, A.; Emanuel, A.S.; Bernath, J.A. [Chevron Petroleum Technology Company, LaHabra, CA (United States)
1997-08-01T23:59:59.000Z
The application of streamtube models for reservoir simulation has an extensive history in the oil industry. Although these models are strictly applicable only to fields under voidage balance, they have proved to be useful in a large number of fields provided that there is no solution gas evolution and production. These models combine the benefit of very fast computational time with the practical ability to model a large reservoir over the course of its history. These models do not, however, directly incorporate the detailed geological information that recent experience has taught is important. This paper presents a technique for mapping the saturation information contained in a history matched streamtube model onto a detailed geostatistically derived finite difference grid. With this technique, the saturation information in a streamtube model, data that is actually statistical in nature, can be identified with actual physical locations in a field and a picture of the remaining oil saturation can be determined. Alternatively, the streamtube model can be used to simulate the early development history of a field and the saturation data then used to initialize detailed late time finite difference models. The proposed method is presented through an example application to the Ninian reservoir. This reservoir, located in the North Sea (UK), is a heterogeneous sandstone characterized by a line drive waterflood, with about 160 wells, and a 16 year history. The reservoir was satisfactorily history matched and mapped for remaining oil saturation. A comparison to 3-D seismic survey and recently drilled wells have provided preliminary verification.
MEASUREMENTS AND MODELING OF EDDY CURRENT EFFECTS IN BNL'S AGS BOOSTER.
BROWN, K.A.; AHRENS, L.; GARDNER, C.; GLENN, J.W.; HARVEY, M.; MENG, W.; ZENO, K.
2006-06-23T23:59:59.000Z
Recent beam experiments at BNL's AGS Booster have enabled us to study in more detail the effects of eddy currents on the lattice structure and our control over the betatron tune. The Booster is capable of operating at ramp rates as high as 9 T/sec. At these ramp rates eddy currents in the vacuum chambers significantly alter the fields and gradients seen by the beam as it is accelerated. The Booster was designed with these effects in mind and to help control the field uniformity and linearity in the Booster Dipoles special vacuum chambers were designed with current windings to negate the affect of the induced eddy currents. In this report results from betatron tune measurements and eddy current simulations will be presented. We will then present results from modeling the accelerator using the results of the magnetic field simulations and compare these to the measurements.
A Metascalable Computing Framework for Large Spatiotemporal-Scale Atomistic Simulations
Nomura, K; Seymour, R; Wang, W; Kalia, R; Nakano, A; Vashishta, P; Shimojo, F; Yang, L H
2009-02-17T23:59:59.000Z
A metascalable (or 'design once, scale on new architectures') parallel computing framework has been developed for large spatiotemporal-scale atomistic simulations of materials based on spatiotemporal data locality principles, which is expected to scale on emerging multipetaflops architectures. The framework consists of: (1) an embedded divide-and-conquer (EDC) algorithmic framework based on spatial locality to design linear-scaling algorithms for high complexity problems; (2) a space-time-ensemble parallel (STEP) approach based on temporal locality to predict long-time dynamics, while introducing multiple parallelization axes; and (3) a tunable hierarchical cellular decomposition (HCD) parallelization framework to map these O(N) algorithms onto a multicore cluster based on hybrid implementation combining message passing and critical section-free multithreading. The EDC-STEP-HCD framework exposes maximal concurrency and data locality, thereby achieving: (1) inter-node parallel efficiency well over 0.95 for 218 billion-atom molecular-dynamics and 1.68 trillion electronic-degrees-of-freedom quantum-mechanical simulations on 212,992 IBM BlueGene/L processors (superscalability); (2) high intra-node, multithreading parallel efficiency (nanoscalability); and (3) nearly perfect time/ensemble parallel efficiency (eon-scalability). The spatiotemporal scale covered by MD simulation on a sustained petaflops computer per day (i.e. petaflops {center_dot} day of computing) is estimated as NT = 2.14 (e.g. N = 2.14 million atoms for T = 1 microseconds).
A numerical model of aerosol scavenging. Part 2, Simulation of a large city fire
Bradley, M.M.; Molenkamp, C.R.
1991-10-01T23:59:59.000Z
Using a three-dimensional numerical cloud/smoke-plume model, we have simulated the burning of a large, mid-latitude city following a nuclear exchange. The model includes 18 dynamic and microphysical equations that predict the fire-driven airflow, cloud processes, and smoke-cloud interactions. In the simulation, the intense heating from the burning city produces a firestorm with updraft velocities exceeding 60 m/s. Within 15 minutes of ignition, the smoke plume penetrates the tropopause. The updraft triggers a cumulonimbus cloud that produces significant quantities of ice, snow, and hail. These solid hydrometeors, as well as cloud droplets and rain, interact with the smoke particles from the fire. At the end of the one-hour simulation, over 20% of the smoke is in slowly falling snowflakes. If the snow reaches the ground before the flakes completely sublimate (or melt and then evaporate), then only approximately 50% of the smoke will survive the scavenging processes and remain in the atmosphere to affect the global climate.
Process Design by FEM Simulation for Shape Ring Rolling of Large-Sized Ring
Lee, Y. S.; Lee, M. W. [Materials Deformation Group, Korea Institute of Materials Science.531 Changwondaero, Changwon, Gyeongsangnam 641-831 (Korea, Republic of); Park, S. S.; Lee, I. [Forging Production Division, Unison Co., Ltd. 1984, Chojeon-Ri, Sanam-Myeon, Sacheon-Si, Gyeongsangnam-Do (Korea, Republic of); Moon, Y. H. [Engineering Research Center for Net Shape and Die Manufacturing, Pusan National University, 30 Jangeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of)
2010-06-15T23:59:59.000Z
Ring rolling process is usually used to fabricate large-sized ring, such as, tower flange for wind power electric generator. Many kinds of seamless ring are used in wind power electric generator and manufactured by ring rolling process. In general, final part is machined after forming with shape of plain square section. Since interests for near net shaping of seamless ring have been increased gradually because of green energy, it is necessary to develop the technology for shape ring rolling with respect to the market demands and cost. Therefore, we studied the process and die design for shape ring rolling of large sized ring over 3,500 mm out diameter by experiment and FEM simulation. Ring rolling process is very difficult to solve by FEM method because of equilibrium state and size effect, etc. Moreover, shape ring rolling is more difficult to solve the problem that two plastic deformation zones are different each other, that is main roll and conical roll. Also since conical roll has a shape, deformation velocity field is very much complex and the deformed section passed axial roll is different section and velocity field. The FE simulations are performed to analyze process variables affected in forming of profiled ring. Therefore, the main features of used FE model are: (1) it adopts a transient or unsteady state full ring mesh to model the deformation processes and shape development; (2) the mandrel and conical rolls are modeled using coupled heat-transfer elements; (3) the model involves the full process from blank through perform to final profiled ring. From these calculated results, we have proposed the mechanisms of various tools, such as mandrel and conical roll. The calculated results are compared experimental results. Calculated results can predict the tilting of profiled ring and then process variables to form large sized ring.
Properties of liquid clusters in large-scale molecular dynamics nucleation simulations
Angélil, Raymond; Diemand, Jürg [Institute for Theoretical Physics, University of Zurich, 8057 Zurich (Switzerland)] [Institute for Theoretical Physics, University of Zurich, 8057 Zurich (Switzerland); Tanaka, Kyoko K.; Tanaka, Hidekazu [Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 (Japan)] [Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 (Japan)
2014-02-21T23:59:59.000Z
We have performed large-scale Lennard-Jones molecular dynamics simulations of homogeneous vapor-to-liquid nucleation, with 10{sup 9} atoms. This large number allows us to resolve extremely low nucleation rates, and also provides excellent statistics for cluster properties over a wide range of cluster sizes. The nucleation rates, cluster growth rates, and size distributions are presented in Diemand et al. [J. Chem. Phys. 139, 74309 (2013)], while this paper analyses the properties of the clusters. We explore the cluster temperatures, density profiles, potential energies, and shapes. A thorough understanding of the properties of the clusters is crucial to the formulation of nucleation models. Significant latent heat is retained by stable clusters, by as much as ?kT = 0.1? for clusters with size i = 100. We find that the clusters deviate remarkably from spherical—with ellipsoidal axis ratios for critical cluster sizes typically within b/c = 0.7 ± 0.05 and a/c = 0.5 ± 0.05. We examine cluster spin angular momentum, and find that it plays a negligible role in the cluster dynamics. The interfaces of large, stable clusters are thinner than planar equilibrium interfaces by 10%?30%. At the critical cluster size, the cluster central densities are between 5% and 30% lower than the bulk liquid expectations. These lower densities imply larger-than-expected surface areas, which increase the energy cost to form a surface, which lowers nucleation rates.
Shrestha, Som S [ORNL] [ORNL; Miller, William A [ORNL] [ORNL; Desjarlais, Andre Omer [ORNL] [ORNL
2013-01-01T23:59:59.000Z
Application of radiant barriers and low-emittance surface coatings in residential building attics can significantly reduce conditioning loads from heat flow through attic floors. The roofing industry has been developing and using various radiant barrier systems and low-emittance surface coatings to increase energy efficiency in buildings; however, minimal data are available that quantifies the effectiveness of these technologies. This study evaluates performance of various attic radiant barrier systems under simulated summer daytime conditions and nighttime or low solar gain daytime winter conditions using the large scale climate simulator (LSCS). The four attic configurations that were evaluated are 1) no radiant barrier (control), 2) perforated low-e foil laminated oriented strand board (OSB) deck, 3) low-e foil stapled on rafters, and 4) liquid applied low-emittance coating on roof deck and rafters. All test attics used nominal RUS 13 h-ft2- F/Btu (RSI 2.29 m2-K/W) fiberglass batt insulation on attic floor. Results indicate that the three systems with radiant barriers had heat flows through the attic floor during summer daytime condition that were 33%, 50%, and 19% lower than the control, respectively.
W. Schmidt; J. C. Niemeyer; W. Hillebrandt
2006-01-23T23:59:59.000Z
We present a one-equation subgrid scale model that evolves the turbulence energy corresponding to unresolved velocity fluctuations in large eddy simulations. The model is derived in the context of the Germano consistent decomposition of the hydrodynamical equations. The eddy-viscosity closure for the rate of energy transfer from resolved toward subgrid scales is localised by means of a dynamical procedure for the computation of the closure parameter. Therefore, the subgrid scale model applies to arbitrary flow geometry and evolution. For the treatment of microscopic viscous dissipation a semi-statistical approach is used, and the gradient-diffusion hypothesis is adopted for turbulent transport. A priori tests of the localised eddy-viscosity closure and the gradient-diffusion closure are made by analysing data from direct numerical simulations. As an a posteriori testing case, the large eddy simulation of thermonuclear combustion in forced isotropic turbulence is discussed. We intend the formulation of the subgrid scale model in this paper as a basis for more advanced applications in numerical simulations of complex astrophysical phenomena involving turbulence.
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 - -/e),,sand CERNLand and AssetLandscapingLarge
Eddy mean flow decomposition and eddy diffusivity estimates in the tropical Pacific Ocean
Eddy mean flow decomposition and eddy diffusivity estimates in the tropical Pacific Ocean: 2] Eddy diffusivity of the surface velocity field in the tropical Pacific Ocean was estimated using diffusivity estimates in the tropical Pacific Ocean: 2. Results, J. Geophys. Res., 107(C10), 3154, doi:10
Polak, S.J.; van Welij, J.S.; Wachters, A.J.H.
1983-11-01T23:59:59.000Z
This paper presents a new EDDY current model. This model minimizes the number of unknown per point. The authors also discuss the uniqueness aspects involved.
Master Thesis Proposal Eddy Current Imaging of Electrically Conducting Media
Vuik, Kees
Master Thesis Proposal Eddy Current Imaging of Electrically Conducting Media Domenico Lahaye and optimization techniques en- abling the eddy current imaging of electrically conducting media. Examples: · perform a literature study into topics such as eddy current imaging, inverse problems including
Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider
Bruce, R; Boccone, V; Bracco, C; Brugger, M; Cauchi, M; Cerutti, F; Deboy, D; Ferrari, A; Lari, L; Marsili, A; Mereghetti, A; Mirarchi, D; Quaranta, E; Redaelli, S; Robert-Demolaize, G; Rossi, A; Salvachua, B; Skordis, E; Tambasco, C; Valentino, G; Weiler, T; Vlachoudis, V; Wollmann, D
2014-01-01T23:59:59.000Z
The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010--2013, the LHC was routinely storing protons at 3.5--4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An un-controlled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multi-stage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the co...
Penner, J.E.; Haselman L. Jr.; Edwards, L.L.
1986-10-01T23:59:59.000Z
Smoke from raging fires produced in the aftermath of a major nuclear exchange has been predicted to cause large decreases in surface temperatures. However, the extent of the decrease and even the sign of the temperature change depend on how the smoke is distributed with altitude. We present a model capable of evaluating the initial distribution of lofted smoke above a massive fire. Calculations are shown for a two-dimensional slab version of the model and a full three-dimensional version. The model has been evaluated by simulating smoke heights for the Hamburg firestorm of 1943, and a smaller-scale oil fire which occurred in Long Beach in 1958. Our plume heights for these fires are compared to those predicted by the classical Morton-Taylor-Turner theory for weakly buoyant plumes. We consider the effect of the added buoyancy caused by condensation of waterladen ground level air being carried to high altitude with the convection column, as well as the effects of background wind on the calculated smoke plume heights for several fire intensities. We find that the rise height of the plume depends on the assumed background atmospheric conditions, as well as the fire intensity.
Lagrangian study of transport and mixing in a mesoscale eddy street
Prants, S V; Ponomarev, V I; Uleysky, M Yu; 10.1016/j.ocemod.2011.02.008
2012-01-01T23:59:59.000Z
We use dynamical systems approach and Lagrangian tools to study surface transport and mixing of water masses in a selected coastal region of the Japan Sea with moving mesoscale eddies associated with the Primorskoye Current. Lagrangian trajectories are computed for a large number of particles in an interpolated velocity field generated by a numerical regional multi-layer eddy-resolving circulation model. We compute finite-time Lyapunov exponents for a comparatively long period of time by the method developed and plot the Lyapunov synoptic map quantifying surface transport and mixing in that region. This map uncovers the striking flow structures along the coast with a mesoscale eddy street and repelling material lines. We propose new Lagrangian diagnostic tools --- the time of exit of particles off a selected box, the number of changes of the sign of zonal and meridional velocities --- to study transport and mixing by a pair of strongly interacting eddies often visible at sea-surface temperature satellite imag...
An Efficient Priority Queue for Large FPGA-Based Discrete Event Simulations of
Herbordt, Martin
: Molecular dynamics simulation based on discrete event simulation (DMD) is emerging as an alternative to time Laboratory Department of Electrical and Computer Engineering Boston University; Boston, MA 02215 Abstract
Large-scale simulation of methane dissociation along the West Spitzbergen Margin
Reagan, M.T.
2010-01-01T23:59:59.000Z
and stability of gas hydrate-related bottom-simulatingPotential effects of gas hydrate on human welfare, Proc.simulated domain, extent of gas hydrate stability zone, and
Reduced-Order Models of Zero-Net Mass-Flux Jets for Large-Scale Flow Control Simulations
Mittal, Rajat
Reduced-Order Models of Zero-Net Mass-Flux Jets for Large-Scale Flow Control Simulations Reni Raju computational tools are well suited for modeling the dynamics of zero-net mass-flux actuators, the computational vorticity, (s-1 ) I. Introduction ERO-net mass-flux (ZNMF) actuators or "synthetic jets" have potential
Oak Ridge National Laboratory
Envelope 1. Large Scale Climate Simulator (Building 3144) The LSCS tests roof and/or attic assemblies weighing up to 9000 kg (10 tons) and as high as 1.83 m (6 ft.) under any inhabited climatic and outdoors but also captures a wide range of secondary metrics. 2. Rotatable Guarded Hot Box (Building 3144
Eddy Correlation Systems Receive Upgrade
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign:INEA :Work4/11ComputationalEd Westcott: Legacy in ... EdEddie2
New Eddy Correlation Systems Installed
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy:Nanowire Solar541,9337, 2011R - 445 CU - 2 3NewNew3 New Eddy
Profile hidden Markov models Sean R. Eddy
Eddy, Sean
Profile hidden Markov models Sean R. Eddy Dept. of Genetics, Washington University School of Medicine 4566 Scott Ave., St. Louis MO 63110 USA eddy@genetics.wustl.edu keywords: profiles, hidden Markov models, protein families Abstract Summary: I review the recent literature on profile hid den Markov
Chen, Q.
simulation models for chilled water and heating hot water distribution systems. The simulation model was used in a $2.3 million Ross Street chilled water pipe replacement project at Texas A&M University. A second project conducted at the University... of Texas at San Antonio was used as an example to demonstrate how to identify and design an optimal distribution system by using a simulation model. The author found that the minor losses of these closed loop thermal distribution systems...
Subsurface Defect Detection in Metals with Pulsed Eddy Current
Plotnikov, Yuri A. [GE Global Research Center, One Research Circle, Niskayuna, NY 12309-1135 (United States); Bantz, Walter J. [GE Aircraft Engines M and QTD, 10270 St. Rita Lane, Cincinnati, OH 45215 (United States)
2005-04-09T23:59:59.000Z
The eddy current (EC) method is traditionally used for open surface crack detection in metallic components. Subsurface voids in bulk metals can also be detected by the eddy current devices. Taking into consideration the skin effect in conductive materials, a lower frequency of electromagnetic excitation is used for a deeper penetration. A set of special specimens was designed and fabricated to investigate sensitivity to subsurface voids. Typically, flat bottom holes (FBHs) are used for subsurface defect simulation. This approach is not very representative of real defects for eddy current inspection because the FBH depth extends to the bottom of the specimen. Two-layer specimens with finite depth FBHs were fabricated and scanned with conventional EC of variable frequency. Sensitivity and spatial resolution of EC diminish with flaw depth. The pulsed EC approach was applied for flaw detection at variable distance under the surface. The transient response from multi-layer model was derived and compared to experiments. The multi-frequency nature of pulsed excitation provides effective coverage of a thick layer of material in one pass. Challenging aspects of subsurface flaw detection and visualization using the EC technique are discussed.
Anomalous Scaling of Structure Functions and Dynamic Constraints on Turbulence Simulations
Victor Yakhot; Katepalli R. Sreenivasan
2005-06-20T23:59:59.000Z
The connection between anomalous scaling of structure functions (intermittency) and numerical methods for turbulence simulations is discussed. It is argued that the computational work for direct numerical simulations (DNS) of fully developed turbulence increases as $Re^{4}$, and not as $Re^{3}$ expected from Kolmogorov's theory, where $Re$ is a large-scale Reynolds number. Various relations for the moments of acceleration and velocity derivatives are derived. An infinite set of exact constraints on dynamically consistent subgrid models for Large Eddy Simulations (LES) is derived from the Navier-Stokes equations, and some problems of principle associated with existing LES models are highlighted.
Large-Scale First-Principles Molecular Dynamics simulations on the BlueGene/L Platform
Franchetti, Franz
. Keywords Electronic structure. Molecular Dynamics. Ab initio simulations. First-principles simulations of the electronic properties of the system. The electronic structure calculation is the most time-consuming part the past three decades to the development of efficient implementations of the electronic structure
Modeling and Simulation of Advanced Nano-Scale Very Large Scale Integration Circuits
Zhou, Ying
2010-07-14T23:59:59.000Z
Capacitance comparison between lithography simulated and lay- out for two elbow conductors. . . . . . . . . . . . . . . . . . . . . . . 33 VI Resistance comparison between lithography simulated and layout for two elbow conductors... and new flow. . . . . . . . . . . . . 104 xii LIST OF FIGURES FIGURE Page 1 The lithography challenge. . . . . . . . . . . . . . . . . . . . . . . . . 2 2 Image distortion due to lithography effect. . . . . . . . . . . . . . . . 2 3 The conductors buried...
Lagrangian study of transport and mixing in a mesoscale eddy street
S. V. Prants; M. V. Budyansky; V. I. Ponomarev; M. Yu. Uleysky
2012-02-02T23:59:59.000Z
We use dynamical systems approach and Lagrangian tools to study surface transport and mixing of water masses in a selected coastal region of the Japan Sea with moving mesoscale eddies associated with the Primorskoye Current. Lagrangian trajectories are computed for a large number of particles in an interpolated velocity field generated by a numerical regional multi-layer eddy-resolving circulation model. We compute finite-time Lyapunov exponents for a comparatively long period of time by the method developed and plot the Lyapunov synoptic map quantifying surface transport and mixing in that region. This map uncovers the striking flow structures along the coast with a mesoscale eddy street and repelling material lines. We propose new Lagrangian diagnostic tools --- the time of exit of particles off a selected box, the number of changes of the sign of zonal and meridional velocities --- to study transport and mixing by a pair of strongly interacting eddies often visible at sea-surface temperature satellite images in that region. We develop a technique to track evolution of clusters of particles, streaklines and material lines. The Lagrangian tools used allow us to reveal mesoscale eddies and their structure, to track different phases of the coastal flow, to find inhomogeneous character of transport and mixing on mesoscales and submesoscales and to quantify mixing by the values of exit times and the number of times particles wind around the eddy's center.
Simulating the High Energy Gamma-ray sky seen by the GLAST Large Area Telescope
F. Longo; P. Azzi; D. Bastieri; G. Busetto; Y. Lei; R. Rando; O. Tibolla; L. Baldini; M. Kuss; L. Latronico; N. Omodei; M. Razzano; G. Spandre; P. Boinee; A. De Angelis; M. Frailis; M. Brigida; F. Gargano; N. Giglietto; F. Loparco; M. N. Mazziotta; C. Cecchi; P. Lubrano; F. Marcucci; M. Pepe; G. Tosti; A. Lionetto; A. Morselli; C. Pittori
2005-03-24T23:59:59.000Z
This paper presents the simulation of the GLAST high energy gamma-ray telescope. The simulation package, written in C++, is based on the Geant4 toolkit, and it is integrated into a general framework used to process events. A detailed simulation of the electronic signals inside Silicon detectors has been provided and it is used for the particle tracking, which is handled by a dedicated software. A unique repository for the geometrical description of the detector has been realized using the XML language and a C++ library to access this information has been designed and implemented. A new event display based on the HepRep protocol was implemented. The full simulation was used to simulate a full week of GLAST high energy gamma-ray observations. This paper outlines the contribution developed by the Italian GLAST software group.
Computer Energy Modeling Techniques for Simulation Large Scale Correctional Institutes in Texas
Heneghan, T.; Haberl, J. S.; Saman, N.; Bou-Saada, T. E.
1996-01-01T23:59:59.000Z
using the DOE-2.1E building enegy simulation program to model a 1,000 bed case study correctional unit located in Texas. INTRODUCTION The Texas Department of Criminal Justice (TDCJ) Stephenson unit located in Cuero, Texas was N. Saman, Ph.D., P... building enegy simulation program (LBL 1980; 1981; 1982; 1989; 1994). The second part of the project included evaluating the energy consumption of this prototype unit. This paper presents a methodology that may be used to view and improve simulation...
Author's personal copy Experimental validation of large-scale simulations of dynamic fracture along
Rosakis, Ares J.
in monolithic homo- geneous brittle solids and along weak interfaces between homo- geneous solids has also been for the fitting of parameters. Then, the results of these simulations are validated against those of experiments
Experimental validation of large-scale simulations of dynamic fracture along weak planes
Huerta, Antonio
of the opening-mode crack initiation and the subsequent crack growth phenomenon both in monolithic homo- geneous are often insufficient to completely setup a simulation, which therefore leaves room for the fitting
Eddy current technique for predicting burst pressure
Petri, Mark C. (Yorkville, IL); Kupperman, David S. (Oak Park, IL); Morman, James A. (Woodridge, IL); Reifman, Jaques (Western Springs, IL); Wei, Thomas Y. C. (Downers Grove, IL)
2003-01-01T23:59:59.000Z
A signal processing technique which correlates eddy current inspection data from a tube having a critical tubing defect with a range of predicted burst pressures for the tube is provided. The method can directly correlate the raw eddy current inspection data representing the critical tubing defect with the range of burst pressures using a regression technique, preferably an artificial neural network. Alternatively, the technique deconvolves the raw eddy current inspection data into a set of undistorted signals, each of which represents a separate defect of the tube. The undistorted defect signal which represents the critical tubing defect is related to a range of burst pressures utilizing a regression technique.
Rotating concave eddy current probe
Roach, Dennis P. (Albuquerque, NM); Walkington, Phil (Albuquerque, NM); Rackow, Kirk A. (Albuquerque, NM); Hohman, Ed (Albuquerque, NM)
2008-04-01T23:59:59.000Z
A rotating concave eddy current probe for detecting fatigue cracks hidden from view underneath the head of a raised head fastener, such as a buttonhead-type rivet, used to join together structural skins, such as aluminum aircraft skins. The probe has a recessed concave dimple in its bottom surface that closely conforms to the shape of the raised head. The concave dimple holds the probe in good alignment on top of the rivet while the probe is rotated around the rivet's centerline. One or more magnetic coils are rigidly embedded within the probe's cylindrical body, which is made of a non-conducting material. This design overcomes the inspection impediment associated with widely varying conductivity in fastened joints.
Zhang, Keni; Moridis, G.J.; Wu, Y.-S.; Pruess, K.
2008-07-01T23:59:59.000Z
Simulation of the system behavior of hydrate-bearing geologic media involves solving fully coupled mass- and heat-balance equations. In this study, we develop a domain decomposition approach for large-scale gas hydrate simulations with coarse-granularity parallel computation. This approach partitions a simulation domain into small subdomains. The full model domain, consisting of discrete subdomains, is still simulated simultaneously by using multiple processes/processors. Each processor is dedicated to following tasks of the partitioned subdomain: updating thermophysical properties, assembling mass- and energy-balance equations, solving linear equation systems, and performing various other local computations. The linearized equation systems are solved in parallel with a parallel linear solver, using an efficient interprocess communication scheme. This new domain decomposition approach has been implemented into the TOUGH+HYDRATE code and has demonstrated excellent speedup and good scalability. In this paper, we will demonstrate applications for the new approach in simulating field-scale models for gas production from gas-hydrate deposits.
Negative magnetic eddy diffusivities from test-field method and multiscale stability theory
Alexander Andrievsky; Axel Brandenburg; Alain Noullez; Vladislav Zheligovsky
2015-01-19T23:59:59.000Z
The generation of large-scale magnetic field in the kinematic regime in the absence of an alpha-effect is investigated by following two different approaches, namely the test-field method and multiscale stability theory relying on the homogenisation technique. We show analytically that the former, applied for the evaluation of magnetic eddy diffusivities, yields results that fully agree with the latter. Our computations of the magnetic eddy diffusivity tensor for the specific instances of the parity-invariant flow-IV of G.O. Roberts and the modified Taylor-Green flow in a suitable range of parameter values confirm the findings of previous studies, and also explain some of their apparent contradictions. The two flows have large symmetry groups; this is used to considerably simplify the eddy diffusivity tensor. Finally, a new analytic result is presented: upon expressing the eddy diffusivity tensor in terms of solutions to auxiliary problems for the adjoint operator, we derive relations between magnetic eddy diffusivity tensors that arise for opposite small-scale flows v(x) and -v(x).
Negative magnetic eddy diffusivities from test-field method and multiscale stability theory
Andrievsky, Alexander; Noullez, Alain; Zheligovsky, Vladislav
2015-01-01T23:59:59.000Z
The generation of large-scale magnetic field in the kinematic regime in the absence of an alpha-effect is investigated by following two different approaches, namely the test-field method and multiscale stability theory relying on the homogenisation technique. We show analytically that the former, applied for the evaluation of magnetic eddy diffusivities, yields results that fully agree with the latter. Our computations of the magnetic eddy diffusivity tensor for the specific instances of the parity-invariant flow-IV of G.O. Roberts and the modified Taylor-Green flow in a suitable range of parameter values confirm the findings of previous studies, and also explain some of their apparent contradictions. The two flows have large symmetry groups; this is used to considerably simplify the eddy diffusivity tensor. Finally, a new analytic result is presented: upon expressing the eddy diffusivity tensor in terms of solutions to auxiliary problems for the adjoint operator, we derive relations between magnetic eddy dif...
Eddy-current-induced multipole field calculations.
Sereno, N. S.; Kim, S. H.
2003-10-15T23:59:59.000Z
Time-varying magnetic fields of magnets in booster accelerators induce substantial eddy currents in the vacuum chambers. The eddy currents in turn act to produce various multipole fields that act on the beam. These fields must be taken into account when doing a lattice design. In the APS booster, the relatively long dipole magnets (3 meters) are linearly ramped to accelerate the injected 325 MeV beam to 7 GeV. Substantial dipole and sextupole fields are generated in the elliptical vacuum chamber from the induced eddy currents. In this note, formulas for the induced dipole and sextupole fields are derived for elliptical and rectangular vacuum chambers for a time-varying dipole field. A discussion is given on how to generalize this derivation method to include eddy-current-induced multipole fields from higher multipole magnets (quadrupole, sextupole, etc.). Finally, transient effects are considered.
Numerical Simulation of Displacement Ventilation in a Gymnasium in a Large Space Building
Wu, X.; Li, X.
2006-01-01T23:59:59.000Z
. However, there still remains a lot to do in providing a suitable airflow pattern for competitions, with less energy consumption. Recently the displacement ventilation (DV) system has been adopted in northern Europe. It is used in large spaces...
Modeling ramp compression experiments using large-scale molecular dynamics simulation.
Mattsson, Thomas Kjell Rene; Desjarlais, Michael Paul; Grest, Gary Stephen; Templeton, Jeremy Alan; Thompson, Aidan Patrick; Jones, Reese E.; Zimmerman, Jonathan A.; Baskes, Michael I. (University of California, San Diego); Winey, J. Michael (Washington State University); Gupta, Yogendra Mohan (Washington State University); Lane, J. Matthew D.; Ditmire, Todd (University of Texas at Austin); Quevedo, Hernan J. (University of Texas at Austin)
2011-10-01T23:59:59.000Z
Molecular dynamics simulation (MD) is an invaluable tool for studying problems sensitive to atomscale physics such as structural transitions, discontinuous interfaces, non-equilibrium dynamics, and elastic-plastic deformation. In order to apply this method to modeling of ramp-compression experiments, several challenges must be overcome: accuracy of interatomic potentials, length- and time-scales, and extraction of continuum quantities. We have completed a 3 year LDRD project with the goal of developing molecular dynamics simulation capabilities for modeling the response of materials to ramp compression. The techniques we have developed fall in to three categories (i) molecular dynamics methods (ii) interatomic potentials (iii) calculation of continuum variables. Highlights include the development of an accurate interatomic potential describing shock-melting of Beryllium, a scaling technique for modeling slow ramp compression experiments using fast ramp MD simulations, and a technique for extracting plastic strain from MD simulations. All of these methods have been implemented in Sandia's LAMMPS MD code, ensuring their widespread availability to dynamic materials research at Sandia and elsewhere.
A Parallel P^3M Code for Very Large Scale Cosmological Simulations
Tom MacFarland; Jakob Pichlmeier; Frazer Pearce; Hugh Couchman
1997-08-07T23:59:59.000Z
We have developed a parallel Particle-Particle, Particle-Mesh (P^3M) simulation code for the T3E well suited to studying the time evolution of systems of particles interacting via gravity and gas forces in cosmological contexts. The parallel code is based upon the public-domain serial Adaptive P^3M code of Couchman et al(1). The algorithm resolves gravitational forces into a long range component computed by discretizing the mass distribution and solving Poisson's equation on a grid using an FFT convolution method, and a short range component computed by direct force summation for sufficiently close particle pairs. The code consists primarily of a particle-particle computation parallelized by domain decomposition over blocks of neighbor-cells, a more regular mesh calculation distributed in planes along one dimension, and several transformations between the two distributions. Great care was taken throughout to make optimal use of the available memory, so that the current implementation is capable of simulating systems approaching 10^9 particles using a 1024^3 mesh for the long range force computation. These are thus among the largest N-body simulations ever carried out. We discuss these memory optimizations as well as those motivated by computational performance. Results from production runs have been very encouraging, and even prior to the implimentation of the full adaptive scheme the code has been used effectively for simulations in which the particle distribution becomes highly clustered as well as for other non-uniform systems of astrophysical interest.
Crack detection using pulsed eddy current stimulated thermography
Kostson, E.; Weekes, B.; Almond, D. P. [RCNDE, Department of Mechanical Engineering, University of Bath (United Kingdom); Wilson, J.; Tian, G. Y. [School of Electrical, Electronic and Computer Engineering, Newcastle University (United Kingdom)
2011-06-23T23:59:59.000Z
This contribution presents results from studies investigating factors that influence the detection of surface breaking cracks using pulsed eddy current thermography. The influences of the current strength and crack orientation in both ferromagnetic and non-ferromagnetic metals have been investigated. It has been found that crack detection is far more sensitive to crack orientation in non-ferromagnetic metals than in ferromagnetic metals. The effects of crack size on detectability are presented for a large number of steel, nickel alloy and titanium samples. Results of studies comparing crack images obtained prior and after coating a nickel alloy sample with a thermal barrier coating are presented.
Klein, Stephen A.; Pincus, Robert; Xu, Kuan-man
2003-06-23T23:59:59.000Z
Cloud parameterizations in large-scale models struggle to address the significant non-linear effects of radiation and precipitation that arise from horizontal inhomogeneity in cloud properties at scales smaller than the grid box size of the large-scale models. Statistical cloud schemes provide an attractive framework to self-consistently predict the horizontal inhomogeneity in radiation and microphysics because the probability distribution function (PDF) of total water contained in the scheme can be used to calculate these non-linear effects. Statistical cloud schemes were originally developed for boundary layer studies so extending them to a global model with many different environments is not straightforward. For example, deep convection creates abundant cloudiness and yet little is known about how deep convection alters the PDF of total water or how to parameterize these impacts. These issues are explored with data from a 29 day simulation by a cloud resolving model (CRM) of the July 1997 ARM Intensive Observing Period at the Southern Great Plains site. The simulation is used to answer two questions: (a) how well can the beta distribution represent the PDFs of total water relative to saturation resolved by the CRM? (b) how can the effects of convection on the PDF be parameterized? In addition to answering these questions, additional sections more fully describe the proposed statistical cloud scheme and the CRM simulation and analysis methods.
Buckingham, A.C.; Siekhaus, W.J.; Keller, J.O.; Ellzey, J.; Hubbard, G.; Daily, J.W.
1982-05-20T23:59:59.000Z
We are investigating the interactive process between turbulent flow and dispersed phase particles. We are focusing on the mechanisms that appear to result in a reduction of local turbulent intensity and a corresponding reduction in wall heat transfer and subsequent wall erosion in turbulent solid propellant combustion flow. We apply computational simulations and physical experiments specialized to a developing free shear layer over a rearward facing step and over a parallel splitter plate. The flow configuration evolves in a two-dimensional, steady, combustion and non-combustion turbulent free shear mixing region, with and without particle additives. The computational simulations combine three basic components: gas phase Navier-Stokes solutions, Lagrange particle field solutions and a Monte Carlo technique for the random encounters, forces and accelerations between the two fields. We concentrate here on relatively large sized additive particles (of the order of tens of microns to 100 microns mean diameter). We examine their apparent influence in breaking up the larger, energy bearing eddy structures into smaller structures which are more readily dissipated.
Rupture mechanism of liquid crystal thin films realized by large-scale molecular simulations
Nguyen, Trung D [ORNL] [ORNL; Carrillo, Jan-Michael Y [ORNL] [ORNL; Brown, W Michael [ORNL] [ORNL; Matheson, Michael A [ORNL] [ORNL
2014-01-01T23:59:59.000Z
The ability of liquid crystal (LC) molecules to respond to changes in their environment makes them an interesting candidate for thin film applications, particularly in bio-sensing, bio-mimicking devices, and optics. Yet the understanding of the (in)stability of this family of thin films has been limited by the inherent challenges encountered by experiment and continuum models. Using unprecedented largescale molecular dynamics (MD) simulations, we address the rupture origin of LC thin films wetting a solid substrate at length scales similar to those in experiment. Our simulations show the key signatures of spinodal instability in isotropic and nematic films on top of thermal nucleation, and importantly, for the first time, evidence of a common rupture mechanism independent of initial thickness and LC orientational ordering. We further demonstrate that the primary driving force for rupture is closely related to the tendency of the LC mesogens to recover their local environment in the bulk state. Our study not only provides new insights into the rupture mechanism of liquid crystal films, but also sets the stage for future investigations of thin film systems using peta-scale molecular dynamics simulations.
Dominguez, O; Maury, H; Rumolo, G; Zimmermann, F
2011-01-01T23:59:59.000Z
After reviewing the basic features of electron clouds in particle accelerators, the pertinent vacuum-chamber surface properties, and the electron-cloud simulation tools in use at CERN, we report recent observations of electron-cloud phenomena at the Large Hadron Collider (LHC) and ongoing attempts to benchmark the measured LHC vacuum pressure increases and heat loads against electron-cloud build-up simulations aimed at determining the actual surface parameters and at monitoring the so-called scrubbing process. Finally, some other electron-cloud studies related to the LHC are mentioned, and future study plans are described. Presented at MulCoPim2011, Valencia, Spain, 21-23 September 2011.
Generation of strong mesoscale eddies by weak ocean gyres by Michael A. Spall1
Generation of strong mesoscale eddies by weak ocean gyres by Michael A. Spall1 ABSTRACT The generation of strong mesoscale variability through instability of the large-scale circulation in the interior with the scaling theory. 1. Introduction It is now well recognized that the kinetic energy of the mesoscale
Three dimensional simulations of Richtmyer-Meshkov instabilities in shock-tube experiments
Gowardhan, Akshay A [Los Alamos National Laboratory; Grinstein, Fernando F [Los Alamos National Laboratory; Wachtor, Adam J [Los Alamos National Laboratory
2010-01-01T23:59:59.000Z
In the large eddy simulation (LES) approach large-scale energy-containing structures are resolved, smaller (presumably) more isotropic structures are filtered out, and unresolved subgrid effects are modeled. Extensive recent work has demonstrated that predictive simulations of turbulent velocity fields are possible based on subgrid scale modeling implicitly provided by a class of high-resolution finite-volume algorithms. This strategy is called implicit LES. The extension of the approach to the substantially more difficult problem of material mixing IS addressed, and progress in representative shock-driven turbulent mixing studies is reported.
A model for red blood cells in simulations of large-scale blood flows
Simone Melchionna
2011-07-25T23:59:59.000Z
Red blood cells (RBCs) are an essential component of blood. A method to include the particulate nature of blood is introduced here with the goal of studying circulation in large-scale realistic vessels. The method uses a combination of the Lattice Boltzmann method (LBM) to account for the plasma motion, and a modified Molecular Dynamics scheme for the cellular motion. Numerical results illustrate the quality of the model in reproducing known rheological properties of blood as much as revealing the effect of RBC structuring on the wall shear stress, with consequences on the development of cardiovascular diseases.
Glider Path-Planning for Optimal Sampling of Mesoscale Eddies
Smith, Ryan N.
Glider Path-Planning for Optimal Sampling of Mesoscale Eddies Daniel Hernandez1 , Ryan Smith2 these, mesoscale eddies are of particular interest due to the relevance they have in many oceano
On the accuracy of N-body simulations at very large scales
Gerasimos Rigopoulos; Wessel Valkenburg
2014-11-25T23:59:59.000Z
We examine the deviation of Cold Dark Matter particle trajectories from the Newtonian result as the size of the region under study becomes comparable to or exceeds the particle horizon. To first order in the gravitational potential, the general relativistic result coincides with the Zel'dovich approximation and hence the Newtonian prediction on all scales. At second order, General Relativity predicts corrections which overtake the corresponding second order Newtonian terms above a certain scale of the order of the Hubble radius. However, since second order corrections are very much suppressed on such scales, we conclude that simulations which exceed the particle horizon but use Newtonian equations to evolve the particles, reproduce the correct trajectories very well. The dominant relativistic corrections to the power spectrum on scales close to the horizon are at most of the order of $\\sim 10^{-5}$ at $z=49$ and $\\sim 10^{-3}$ at $z=0$. The differences in the positions of real space features are affected at a level below $10^{-6}$ at both redshifts. Our analysis also clarifies the relation of N-body results to relativistic considerations.
Demand Shifting With Thermal Mass in Large Commercial Buildings:Field Tests, Simulation and Audits
Xu, Peng; Haves, Philip; Piette, Mary Ann; Zagreus, Leah
2005-09-01T23:59:59.000Z
The principle of pre-cooling and demand limiting is to pre-cool buildings at night or in the morning during off-peak hours, storing cooling in the building thermal mass and thereby reducing cooling loads and reducing or shedding related electrical demand during the peak periods. Cost savings are achieved by reducing on-peak energy and demand charges. The potential for utilizing building thermal mass for load shifting and peak demand reduction has been demonstrated in a number of simulation, laboratory, and field studies (Braun 1990, Ruud et al. 1990, Conniff 1991, Andresen and Brandemuehl 1992, Mahajan et al. 1993, Morris et al. 1994, Keeney and Braun 1997, Becker and Paciuk 2002, Xu et al. 2003). This technology appears to have significant potential for demand reduction if applied within an overall demand response program. The primary goal associated with this research is to develop information and tools necessary to assess the viability of and, where appropriate, implement demand response programs involving building thermal mass in buildings throughout California. The project involves evaluating the technology readiness, overall demand reduction potential, and customer acceptance for different classes of buildings. This information can be used along with estimates of the impact of the strategies on energy use to design appropriate incentives for customers.
of Hispaniola, warm eddies are spun up by the local wind stress curl. This type of eddy drifts southwestward for spin up and drift from Hispaniola is about 100 days. Satellite data indicate the existence
Eddy formation and propagation in the eastern tropical Pacific
Jhingran, Vikas Gopal
1997-01-01T23:59:59.000Z
eddies are caused by winds blowing offshore from the coast of Central America. Plots of eddy tracks from TOPEX data show that some of these eddies last for over 6 months and travel more than 250 of longitude toward the west. Others go more towards...
Eddy Currents and Magnetic Calibrations in LDX using a
Eddy Currents and Magnetic Calibrations in LDX using a "Copper Plasma" D.P. Boyle, PPPL M.E. Mauel Calibrate magnetic diagnostics positions and gains Find eddy current decay times Copper Plasma Operation electronically Would be better to measure positions and total gains magnetically #12;Goal: Eddy Currents Magnetic
Eddy-current testing with the Expected Improvement optimization algorithm
Paris-Sud XI, Université de
Eddy-current testing with the Expected Improvement optimization algorithm S´andor Bilicz , Emmanuel presents an inverse problem methodology in the domain of non-destructive testing, and more precisely eddy-current in the light of preliminary numerical examples obtained using synthetic data. Keywords: eddy current testing
Automatic Detection of Defects in Riveted Lapjoints using Eddy Current
Automatic Detection of Defects in Riveted Lapjoints using Eddy Current Fredrik Lingvall Tadeusz originating from rivet holes in a riveted lapjoint using eddy current (EC) inspection is presented consisted of median filtering, rotation and debiasing of the eddy current pattern. The rotation
A JUSTIFICATION OF EDDY CURRENTS MODEL FOR THE MAXWELL EQUATIONS
Buffa, Annalisa
A JUSTIFICATION OF EDDY CURRENTS MODEL FOR THE MAXWELL EQUATIONS H. AMMARI, A. BUFFA, AND J.-C. NÂ1823 Abstract. This paper is concerned with the approximation of the Maxwell equations by the eddy currents model, which appears as a correction of the quasi-static model. The eddy currents model is obtained
MODELING OF EDDY CURRENT LOSS AND TEMPERATURE OF THE MAGNETS
Mi, Chunting "Chris"
MODELING OF EDDY CURRENT LOSS AND TEMPERATURE OF THE MAGNETS IN PERMANENT MAGNET MACHINES@umich.edu Received 24 November 2010 Accepted 16 June 2011 The eddy current loss in the magnets of permanent magnet- mium-iron-boron (NdFeB), and slot/tooth harmonics, there is eddy current loss generated inside
Nondestructive Evaluation of Plates Using Eddy Current Methods
Nondestructive Evaluation of Plates Using Eddy Current Methods David C. Dobson Department in structures using eddy current methods is investigated. The goal of this work is to assess the extent to which a conductivity anomaly from eddy current data is quite unstable, and a method based on leastsquares principle
STATISTICAL ASSESSMENT OF PROBABILITY OF DETECTION FOR AUTOMATED EDDY CURRENT
STATISTICAL ASSESSMENT OF PROBABILITY OF DETECTION FOR AUTOMATED EDDY CURRENT NONDESTRUCTIVE for Nondestructive Evaluation, Iowa State University, Ames, Iowa, USA Abstract: Eddy current inspection is widely response collected using our motion controlled eddy current inspection system, are used in the analysis
WIRELESS EDDY CURRENT PROBE FOR ENGINE HEALTH , B. Graubard1
Dickerson, Julie A.
WIRELESS EDDY CURRENT PROBE FOR ENGINE HEALTH MONITORING M. Reid1 , B. Graubard1 , R. J. Weber1 , J. The first prototype wireless eddy current (EC) probe for on-wing inspection was demonstrated in a F100 PW of safety significant propulsion system malfunctions. Data from 2 MHz Eddy Current probes was transmitted
ADAPTIVE FINITE ELEMENT FREQUENCY DOMAIN METHOD FOR EDDY CURRENT PROBLEMS
Zheng, Weiying
ADAPTIVE FINITE ELEMENT FREQUENCY DOMAIN METHOD FOR EDDY CURRENT PROBLEMS WEIYING ZHENG-harmonic eddy current problems in the case of three-dimensional isotropic and linear materials. We adopt. Time-harmonic Maxwell's equations, eddy current, adaptive finite element method, multiply connected
HHFW (High Harmonic Fast Wave) Eddy Current Analysis for Antenna
Princeton Plasma Physics Laboratory
1 NSTX HHFW (High Harmonic Fast Wave) Eddy Current Analysis for Antenna NSTX-CALC-24-03-01 June 1 performed.) The model was first built for NSTX to verify the eddy current effect on antenna during plasma force of the induced eddy current in the components. The force data was transferred to the structural
Nondestructive Evaluation of Plates Using Eddy Current Methods
Santosa, Fadil
Nondestructive Evaluation of Plates Using Eddy Current Methods David C. Dobson \\Lambda Department in structures using eddy current methods is investigated. The goal of this work is to assess the extent to which anomaly from eddy current data is quite unstable, and a method based on leastsquares principle would fail
Quantitative Imaging of Corrosion in Plates by Eddy Current Methods
Santosa, Fadil
Quantitative Imaging of Corrosion in Plates by Eddy Current Methods Bruno Luong \\Lambda and Fadil the problem of determining material loss due to corÂ rosion in a plate. Eddy current data are collected on one the relationship between eddy current loop impedance change with the loss profile. In this context, we show
CHARACTERIZATION OF MAGNETRON SPUTTERED COATINGS BY PULSED EDDY CURRENT TECHNIQUES
Danon, Yaron
CHARACTERIZATION OF MAGNETRON SPUTTERED COATINGS BY PULSED EDDY CURRENT TECHNIQUES Chris Mulligan1, Troy, NY 12180 ABSTRACT. A method that uses induced pulsed eddy currents for characterization of thick the correlation between coating properties, such as density and purity, and eddy current measured resistivity
Surfzone eddies in strong alongshore currents: Forced or Instabilities?
Frandsen, Jannette B.
Surfzone eddies in strong alongshore currents: Forced or Instabilities? Falk Feddersen Associate by surfzone 2D turbulent eddies, which have length-scales > the water depth. Our group's results regarding surfzone eddy-induced mixing learned from dye, drifter, theory, and modeling will be reviewed - however
Nondestructive Evaluation of Plates Using Eddy Current Methods
Dobson, David C.
Nondestructive Evaluation of Plates Using Eddy Current Methods David C. Dobson Department in structures using eddy current methods is investigated. The goal of this work is to assess the extent to which anomaly from eddy current data is quite unstable, and a method based on leastsquares principle would fail
Real Time Computational Algorithms for Eddy Current Based Damage Detection
Real Time Computational Algorithms for Eddy Current Based Damage Detection H. T. Banks y, Michele L such damages by application of an eddy current based technique coupled with reduced order modeling. We begin by developing a model for a speci#12;c eddy current method in which we make some simplifying assumptions
Numerical Analysis of Nonlinear Multiharmonic Eddy Current Problems
Schoeberl, Joachim
Numerical Analysis of Nonlinear Multiharmonic Eddy Current Problems F. Bachinger U. Langer J. Sch¨oberl April 2004 Abstract This work provides a complete analysis of eddy current problems, rang- ing from at providing a complete analysis of general nonlinear eddy current problems and their numerical treatment
Surf zone eddies coupled with rip current morphology
Kirby, James T.
Surf zone eddies coupled with rip current morphology Jamie H. MacMahan Oceanography Department. Thornton, and T. P. Stanton (2004), Surf zone eddies coupled with rip current morphology, J. Geophys. Res) surf zone eddies (SZEs) were observed on a beach composed of shore-connected shoals with quasi
Corner singularities of Maxwell interface and eddy current problems
Costabel, Martin
Corner singularities of Maxwell interface and eddy current problems Martin Costabel, Monique Dauge permittivity/conductivity tends to zero (the eddy current limit). Corner singularities of the Maxwell transmission problem and also of the eddy current model have been described elsewhere [6, 7]. Here we
Eddy formation and propagation in the eastern tropical Pacific
Jhingran, Vikas Gopal
1997-01-01T23:59:59.000Z
eddies are caused by winds blowing offshore from the coast of Central America. Plots of eddy tracks from TOPEX data show that some of these eddies last for over 6 months and travel more than 250 of longitude toward the west. Others go more towards...
MESOSCALE EDDIES Peter B. Rhines, University of Washington,
MESOSCALE EDDIES Peter B. Rhines, University of Washington, School of Oceanography, Box 357940, Seattle, WA 98195 7940, USA Copyright ^ 2001 Academic Press doi:10.1006/rwos.2001.0143 Mesoscale eddies that strongly feel viscosity, to `mesoscale eddies' that strongly feel the Earth's rota- tion, to great `gyres
Casimir interaction from magnetically coupled eddy currents
Francesco Intravaia; Carsten Henkel
2009-09-06T23:59:59.000Z
We study the quantum and thermal fluctuations of eddy (Foucault) currents in thick metallic plates. A Casimir interaction between two plates arises from the coupling via quasi-static magnetic fields. As a function of distance, the relevant eddy current modes cross over from a quantum to a thermal regime. These modes alone reproduce previously discussed thermal anomalies of the electromagnetic Casimir interaction between good conductors. In particular, they provide a physical picture for the Casimir entropy whose nonzero value at zero temperature arises from a correlated, glassy state.
Casimir Interaction from Magnetically Coupled Eddy Currents
Intravaia, Francesco; Henkel, Carsten [Institut fuer Physik und Astronomie, Universitaet Potsdam, 14476 Potsdam (Germany)
2009-09-25T23:59:59.000Z
We study the quantum and thermal fluctuations of eddy (Foucault) currents in thick metallic plates. A Casimir interaction between two plates arises from the coupling via quasistatic magnetic fields. As a function of distance, the relevant eddy current modes cross over from a quantum to a thermal regime. These modes alone reproduce previously discussed thermal anomalies of the electromagnetic Casimir interaction between good conductors. In particular, they provide a physical picture for the Casimir entropy whose nonzero value at zero temperature arises from a correlated, glassy state.
Eddy Correlation Flux Measurement System (ECOR) Handbook
Cook, DR
2011-01-31T23:59:59.000Z
The eddy correlation (ECOR) flux measurement system provides in situ, half-hour measurements of the surface turbulent fluxes of momentum, sensible heat, latent heat, and carbon dioxide (CO2) (and methane at one Southern Great Plains extended facility (SGP EF) and the North Slope of Alaska Central Facility (NSA CF). The fluxes are obtained with the eddy covariance technique, which involves correlation of the vertical wind component with the horizontal wind component, the air temperature, the water vapor density, and the CO2 concentration.
Statistical Analyses of Scatterplots to Identify Important Factors in Large-Scale Simulations
Kleijnen, J.P.C.; Helton, J.C.
1999-04-01T23:59:59.000Z
The robustness of procedures for identifying patterns in scatterplots generated in Monte Carlo sensitivity analyses is investigated. These procedures are based on attempts to detect increasingly complex patterns in the scatterplots under consideration and involve the identification of (1) linear relationships with correlation coefficients, (2) monotonic relationships with rank correlation coefficients, (3) trends in central tendency as defined by means, medians and the Kruskal-Wallis statistic, (4) trends in variability as defined by variances and interquartile ranges, and (5) deviations from randomness as defined by the chi-square statistic. The following two topics related to the robustness of these procedures are considered for a sequence of example analyses with a large model for two-phase fluid flow: the presence of Type I and Type II errors, and the stability of results obtained with independent Latin hypercube samples. Observations from analysis include: (1) Type I errors are unavoidable, (2) Type II errors can occur when inappropriate analysis procedures are used, (3) physical explanations should always be sought for why statistical procedures identify variables as being important, and (4) the identification of important variables tends to be stable for independent Latin hypercube samples.
Isolating the role of mesoscale eddies in mixing of a passive tracer in an eddy resolving model
Miami, University of
Isolating the role of mesoscale eddies in mixing of a passive tracer in an eddy resolving model February 2008; published 16 May 2008. [1] This study examines the role of mesoscale eddies in distribution was replaced by a down-gradient diffusive parameterization. Our results demonstrate that advection by mesoscale
Bogliolo, Alessandro
for design evaluation. A large number of power estimation techniques has been proposed [1]Â[4] based, the large number of simulations needed to reach a significant estimate of average power dissipation further and valida- tion. When optimizing for power, several transformations are applied to a circuit to reduce its
J. E. O'Brien; M. G. McKellar; E. A. Harvego; C. M. Stoots
2009-05-01T23:59:59.000Z
A research and development program is under way at the Idaho National Laboratory (INL) to assess the technological and scale-up issues associated with the implementation of solid-oxide electrolysis cell technology for efficient high-temperature hydrogen production from steam. This work is supported by the US Department of Energy, Office of Nuclear Energy, under the Nuclear Hydrogen Initiative. This paper will provide an overview of large-scale system modeling results and economic analyses that have been completed to date. System analysis results have been obtained using the commercial code UniSim, augmented with a custom high-temperature electrolyzer module. Economic analysis results were based on the DOE H2A analysis methodology. The process flow diagrams for the system simulations include an advanced nuclear reactor as a source of high-temperature process heat, a power cycle and a coupled steam electrolysis loop. Several reactor types and power cycles have been considered, over a range of reactor outlet temperatures. Pure steam electrolysis for hydrogen production as well as coelectrolysis for syngas production from steam/carbon dioxide mixtures have both been considered. In addition, the feasibility of coupling the high-temperature electrolysis process to biomass and coal-based synthetic fuels production has been considered. These simulations demonstrate that the addition of supplementary nuclear hydrogen to synthetic fuels production from any carbon source minimizes emissions of carbon dioxide during the production process.
Accelerated Profile HMM Searches Sean R. Eddy *
Eddy, Sean
Accelerated Profile HMM Searches Sean R. Eddy * Abstract Profile hidden Markov models (profile HMMs search. However, practical use of profile HMM methods has been hindered by the computational expense of existing software implementations. Here I describe an acceleration heuristic for profile HMMs
Fedorczak, N. [Center for Momentum Transport and Flow Organization, University of California at San Diego, San Diego, California 92093 (United States); CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Manz, P. [Center for Momentum Transport and Flow Organization, University of California at San Diego, San Diego, California 92093 (United States); Max-Planck-Institut feur Plasmaphysik, Association Euratom-IPP, 85748Garching (Germany); Thakur, S. C.; Xu, M.; Tynan, G. R. [Center for Momentum Transport and Flow Organization, University of California at San Diego, San Diego, California 92093 (United States); Xu, G. S.; Liu, S. C. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)
2012-12-15T23:59:59.000Z
Time delay estimation (TDE) techniques are frequently used to estimate the flow velocity from fluctuating measurements. Tilted structures carried by the flow lead to misinterpretation of the time delays in terms of velocity direction and amplitude. It affects TDE measurements from probes, and is also intrinsically important for beam emission spectroscopy and gas puff imaging measurements. Local eddy shapes estimated from 2D fluctuating field are necessary to gain a more accurate flow estimate from TDE, as illustrated by Langmuir probe array measurements. A least square regression approach is proposed to estimate both flow field and shaping parameters. The technique is applied to a test case built from numerical simulation of interchange fluctuations. The local eddy shape does not only provide corrections for the velocity field but also quantitative information about the statistical interaction mechanisms between local eddies and E Multiplication-Sign B flow shear. The technique is then tested on gaz puff imaging data collected at the edge of EAST tokamak plasmas. It is shown that poloidal asymmetries of the fluctuation fields-velocity and eddy shape-are consistent at least qualitatively with a ballooning type of turbulence immersed in a radially sheared equilibrium flow.
Aldrin, John C. [Computational Tools, Gurnee, IL 60031 (United States); Sabbagh, Harold A.; Murphy, R. Kim; Sabbagh, Elias H. [Victor Technologies LLC, Bloomington, IN 47401 (United States)
2011-06-23T23:59:59.000Z
Recent advances are presented to model discontinuities in random anisotropies that arise in certain materials, such as titanium alloys. A numerical model is developed to provide a full anisotropic representation of each crystalline in a gridded region of the material. Several simulated and experimental demonstrations are presented highlighting the effect of grain noise on eddy current measurements. Agreement between VIC-3D(c) model calculations and experimental data in titanium alloy specimens with known flaws is demonstrated.
Mitchell, John Anthony; Epp, David S.; Wittwer, Jonathan W.
2005-10-01T23:59:59.000Z
Damping vibrations is important in the design of some types of inertial sensing devices. One method for adding damping to a device is to use magnetic forces generated by a static magnetic field interacting with eddy currents. In this report, we develop a 2-dimensional finite element model for the analysis of quasistatic eddy currents in a thin sheet of conducting material. The model was used for design and sensitivity analyses of a novel mechanical oscillator that consists of a shuttle mass (thin sheet of conducting material) and a set of folded spring elements. The oscillator is damped through the interaction of a static magnetic field and eddy currents in the shuttle mass. Using a prototype device and Laser Dopler Velocimetry (LDV), measurements were compared to the model in a validation study using simulation based uncertainty analyses. Measurements were found to follow the trends predicted by the model.
Contoured Surface Eddy Current Inspection System
Batzinger, Thomas James (Burnt Hills, NY); Fulton, James Paul (Clifton Park, NY); Rose, Curtis Wayne (Mechanicville, NY); Perocchi, Lee Cranford (Schenectady, NY)
2003-04-08T23:59:59.000Z
Eddy current inspection of a contoured surface of a workpiece is performed by forming a backing piece of flexible, resiliently yieldable material with a contoured exterior surface conforming in shape to the workpiece contoured surface. The backing piece is preferably cast in place so as to conform to the workpiece contoured surface. A flexible eddy current array probe is attached to the contoured exterior surface of the backing piece such that the probe faces the contoured surface of the workpiece to be inspected when the backing piece is disposed adjacent to the workpiece. The backing piece is then expanded volumetrically by inserting at least one shim into a slot in the backing piece to provide sufficient contact pressure between the probe and the workpiece contoured surface to enable the inspection of the workpiece contoured surface to be performed.
Hamann, Bernd
JOURNAL OF GEOPHYSICAL RESEARCH: OCEANS, VOL. 118, 17591 , doi:10.1002/jgrc.20155, 2013 A three-dimensional eddy census of a high-resolution global ocean simulation Mark R. Petersen,1 Sean J. Williams,1,2 Mathew from a global ocean simulation with one-tenth degree resolution and a duration of 7 years. The census
INNOVATIVE EDDY CURRENT PROBE FOR MICRO DEFECTS
Santos, Telmo G.; Vilaca, Pedro; Quintino, Luisa [IDMEC, Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Santos, Jorge dos [GKSS, Max-Planck-Street 1, D-21502 Geesthacht (Germany); Rosado, Luis [IST, UTL, Av. Rovisco Pais, 1049-001 Lisbon (Portugal)
2010-02-22T23:59:59.000Z
This paper reports the development of an innovative eddy current (EC) probe, and its application to micro-defects on the root of the Friction Stir Welding (FSW). The new EC probe presents innovative concept issues, allowing 3D induced current in the material, and a lift-off independence. Validation experiments were performed on aluminium alloys processed by FSW. The results clearly show that the new EC probe is able to detect and sizing surface defects about 60 microns depth.
Eddy current inspection tool. [Patent application
Petrini, R.R.; Van Lue, D.F.
1980-10-29T23:59:59.000Z
A miniaturized inspection tool, for testing and inspection of metal objects in locations with difficult accessibility, which comprises eddy current sensing equipment with a probe coil, and associated coaxial coil cable, oil energizing means, and circuit means responsive to impedance changes in the coil as effected by induced eddy currents in a test object to produce a data output signal proportional to such changes. The coil and cable are slideably received in the utility channel of the flexible insertion tube of a fiberoptic scope. The scope is provided with light transmitting and receiving fiberoptics for viewing through the flexible tube, and articulation means for articulating the distal end of the tube and permitting close control of coil placement relative to a test object. The eddy current sensing equipment includes a tone generator for generating audible signals responsive to the data output signal. In one selected mode of operation, the tone generator responsive to the output signal above a selected level generates a constant single frequency tone for signalling detection of a discontinuity and, in a second selected mode, generates a tone whose frequency is proportional to the difference between the output signal and a predetermined selected threshold level.
Adaptive finite element method for eddy current problems
Adaptive finite element method for eddy current problems. In this chapter we shall discuss Maxwell's equations at very low frequencies. We also refer to [bo98 ...
automated eddy current: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
model-assisted POD study. Keywords 2 AUTOMATED ANALYSIS OF EDDY CURRENT SIGNALS IN STEAM GENERATOR TUBE INSPECTION CiteSeer Summary: Abstract: Accurate and consistent...
A TRANSIENT EDDY CURRENT PROBLEM ON A MOVING DOMAIN. MATHEMATICAL ANALYSIS
RodrÃguez, Rodolfo
A TRANSIENT EDDY CURRENT PROBLEM ON A MOVING DOMAIN. MATHEMATICAL ANALYSIS ALFREDO BERM is to introduce and analyze a weak formulation of the transient eddy current problem governing electromagnetic. Electromagnetic forming, transient eddy current problem, axisymmetric problem, degenerate parabolic problem
RodrÃguez, Rodolfo
Numerical solution of transient eddy current problems with input current intensities as boundary to solve transient eddy current problems with input current intensities as data, formulated in terms: Eddy current problems, time-dependent electromagnetic problems, input current intensities, finite
MATHEMATICAL AND NUMERICAL ANALYSIS OF A TRANSIENT EDDY CURRENT PROBLEM ARISING FROM
RodrÃguez, Rodolfo
MATHEMATICAL AND NUMERICAL ANALYSIS OF A TRANSIENT EDDY CURRENT PROBLEM ARISING FROM transient axisymmetric eddy current problem governing such phenomenon. The resulting problem is degenerate. Electromagnetic forming, finite elements, eddy current, transient electromagnetics, degenerate parabolic problems
Banerjee, Sibashis Sanatkumar
1994-01-01T23:59:59.000Z
the RELAP5/MOD3 thermal hydraulic code. The experiment was conducted at the Rig of Safety Assessment (ROSA)-IV/ Large Scale Test Facility (LSTF). The experiment involved a 5% cold leg break along with the loss of the RHR system-The transient was simulated...
Satyanarayanan, Mahadev "Satya"
A majorfeature ofthe VAX-lI is its large virtual address space. This trace-driven simulation scheme evaluates address translation hardware that supports thisfeature cost-effectively. Design Trade-Offs in VAX- dress space was a primary goal of VAX architects. (Over- views of VAX architecture are given
Minnesota, University of
the Agulhas Current, which flows along the southeastern coast of Africa and around the tip of South Africa dynamics. In addition to dominating the ocean's kinetic energy, eddies play a significant role. The ocean's kinetic energy is dominated by mesoscale variability: scales of tens to hundreds of kilometers
Wang, Weiguo; Davis, Kenneth J.
2008-09-03T23:59:59.000Z
We compare the contributions of unit source fluxes over a clear-cutting area in a forest and over the contiguous forested area to the eddy-covariance (EC) flux of CO2 measured at a tower standing in the center of the clearcut under daytime convective conditions. The large-eddy simulation (LES) technique is used to simulate the dispersion and transport of two conservative and passive tracers that are released from the clearcut and from the forested area, respectively. The time series of the LES-generated vertical velocity and the mixing ratios of both tracers on all the levels at the tower location are recorded every model time step during the last hour of each LES run; this somewhat mimics real EC flux measurements at the tower. The contribution of the unit surface flux over the clearcut relative to that over the forested area decreases exponentially with increasing measurement height, decreasing convective boundary layer depth, increasing atmospheric stability, and decreasing size of the clearcut. LES-derived results are fitted to an empirical relation and applied to flux measurements at the 447-m tall tower in Wisconsin, USA. The contribution of the unit flux over the clearcut on the EC flux measured at the 30-m level of the tower is larger than 50% of that over the forested area under most unstable conditions, while smaller than 2.5% at the 396-m level. Existing analytical footprint models are inappropriate to address the clearcut influence due to clearcut-induced heterogeneity of the turbulent flow in the tower area.
Casimir interaction from magnetically coupled eddy currents
Intravaia, Francesco
2009-01-01T23:59:59.000Z
We study the Casimir interaction due to eddy (Foucault) currents in thick metallic plates. The Drude model is used to describe the optical response of the metal at low frequencies. A repulsive force arises from the electromagnetic coupling between chargeless currents filling the metallic half-spaces. We show that these overdamped modes are entirely responsible for the thermal anomalies of the Casimir force between good conductors. It turns out that the applicability of the Nernst heat theorem (third law of thermodynamics) must be reviewed since the ground state of the coupled metal+field system can become highly degenerate at zero temperature.
Eddy current measurement of tube element spacing
Latham, Wayne Meredith (Forest, VA); Hancock, Jimmy Wade (Lynchburg, VA); Grut, Jayne Marie (Madison Heights, VA)
1998-01-01T23:59:59.000Z
A method of electromagnetically measuring the distance between adjacent tube elements in a heat exchanger. A cylindrical, high magnetic permeability ferrite slug is placed in the tube adjacent the spacing to be measured. A bobbin or annular coil type probe operated in the absolute mode is inserted into a second tube adjacent the spacing to be measured. From prior calibrations on the response of the eddy current coil, the signals from the coil, when sensing the presence of the ferrite slug, are used to determine the spacing between the tubes.
Characterization of Caribbean Meso-Scale Eddies Jose M. Lopez
Gilbes, Fernando
Characterization of Caribbean Meso-Scale Eddies Jose M. Lopez Department of Marine Sciences, P-term goal is to improve predictivity of physical, biogeochemical and optical properties of Eastern Caribbean, biological and optical variables across frontal and eddy boundaries in the Eastern Caribbean Sea Â· To develop
Accelerated profile HMM searches Sean R. Eddy1,
Eddy, Sean
1 Accelerated profile HMM searches Sean R. Eddy1, 1 HHMI Janelia Farm Research Campus, Ashburn, VA, USA. E-mail: eddys@janelia.hhmi.org Abstract Profile hidden Markov models (profile HMMs search. However, practical use of profile HMM methods has been hindered by the computational expense
Evaluation of Detached Eddy Simulation for Turbulent Wake Applications
Roy, Chris
coefficient Cl = lift coefficient Cpb = base pressure coefficient D = square cylinder width d = distance coordinate l j = artificial compression method switch = numerical dissipation parameter l j = flux Jacobian
Kemner, Ken
Eddy-Current-Induced Multipole Field Calculations September 29, 2003 1 Eddy-Current-Induced Multipole Field Calculations Nicholas S. Sereno, Suk H. Kim 1.0 Abstract Time-varying magnetic fields-current-induced multipole fields from higher multipole magnets (quadrupole, sextupole, etc.). Finally, transient effects
Eddy Current for Sizing Cracks in Canisters for Dry Storage of Used Nuclear Fuel
Meyer, Ryan M.; Jones, Anthony M.; Pardini, Allan F.
2014-01-01T23:59:59.000Z
The storage of used nuclear fuel (UNF) in dry canister storage systems (DCSSs) at Independent Spent Fuel Storage Installations (ISFSI) sites is a temporary measure to accommodate UNF inventory until it can be reprocessed or transferred to a repository for permanent disposal. Policy uncertainty surrounding the long-term management of UNF indicates that DCSSs will need to store UNF for much longer periods than originally envisioned. Meanwhile, the structural and leak-tight integrity of DCSSs must not be compromised. The eddy current technique is presented as a potential tool for inspecting the outer surfaces of DCSS canisters for degradation, particularly atmospheric stress corrosion cracking (SCC). Results are presented that demonstrate that eddy current can detect flaws that cannot be detected reliably using standard visual techniques. In addition, simulations are performed to explore the best parameters of a pancake coil probe for sizing of SCC flaws in DCSS canisters and to identify features in frequency sweep curves that may potentially be useful for facilitating accurate depth sizing of atmospheric SCC flaws from eddy current measurements.
Guglielmetti, R.; Pless, S.; Torcellini, P.
2010-08-01T23:59:59.000Z
This paper illustrates the challenges of integrating rigorous daylight and electric lighting simulation data with whole-building energy models, and defends the need for such integration to achieve aggressive energy savings. Through a case study example, we examine the ways daylighting -- and daylighting simulation -- drove the design of a large net-zero energy project. We give a detailed review of the daylighting and electric lighting design process for the National Renewable Energy Laboratory's Research Support Facility (RSF), a 220,000 ft2 net-zero energy project the author worked on as a daylighting consultant. A review of the issues involved in simulating and validating the daylighting performance of the RSF will be detailed, including daylighting simulation, electric lighting control response, and integration of Radiance simulation data into the building energy model. Daylighting was a key strategy in reaching the contractual energy use goals for the RSF project; the building's program, layout, orientation and interior/furniture design were all influenced by the daylighting design, and simulation was critical in ensuring these many design components worked together in an integrated fashion, and would perform as required to meet a very aggressive energy performance goal, as expressed in a target energy use intensity.
SOURCE SEPARATION TECHNIQUES APPLIED TO THE DETECTION OF SUBSURFACE DEFECTS IN THE EDDY CURRENT NDT
Paris-Sud XI, Université de
SOURCE SEPARATION TECHNIQUES APPLIED TO THE DETECTION OF SUBSURFACE DEFECTS IN THE EDDY CURRENT NDT component analysis, to process the data from the eddy current inspection of riveted lap joints. An eddy methods are proposed for processing such eddy current data by means of both the considered source
Eddy currents in a gradient coil, modeled as circular loops of strips
Eindhoven, Technische Universiteit
Eddy currents in a gradient coil, modeled as circular loops of strips J.M.B. Kroot, S.J.L. van to induction, eddy currents occur, resulting in a so-called edge-effect. Higher frequencies cause stronger edge by a gradient coil induces eddy currents in the conducting structures. The eddy currents cause perturbations
Feng, Ming
Physical and chemical signatures of a developing anticyclonic eddy in the Leeuwin Current, eastern 2006 to sample a developing anticyclonic eddy of the Leeuwin Current off Western Australia. The eddy to that of the Leeuwin Current, indicating the water mass in the eddy is mainly derived from the Leeuwin Current
Classical eddy current losses in Soft Magnetic Composites , O. de la Barrire2a
Paris-Sud XI, Université de
1 Classical eddy current losses in Soft Magnetic Composites C. Appino1 , O. de la Barrière2a , F. It is known that eddy currents can flow in these granular materials at3 two different scales, that of the single particle (microscopic eddy currents) and that of the specimen4 cross-section (macroscopic eddy
Modeled biogeochemical responses to mesoscale eddies in the South China Sea
Maine, University of
Modeled biogeochemical responses to mesoscale eddies in the South China Sea Peng Xiu1 and Fei Chai1] Mesoscale eddies are observed each year in the South China Sea (SCS); however, their contributions physicalbiogeochemical model to evaluate the eddy impact. We first track the modeled mesoscale eddies in the SCS
Wind ringing of the ocean in presence of mesoscale eddies P. Klein and G. Lapeyre
Lapeyre, Guillaume
Wind ringing of the ocean in presence of mesoscale eddies P. Klein and G. Lapeyre Laboratoire de scales related to oceanic mesoscale eddies. Results show that a turbulent eddy field does not affect Oceanography: Physical: Eddies and mesoscale processes; 4572 Oceanography: Physical: Upper ocean processes
BOUNDARY LAYER (BL) THERMAL EDDIES OVER A PINE FOREST FROM CARES 2010
BOUNDARY LAYER (BL) THERMAL EDDIES OVER A PINE FOREST FROM CARES 2010 Gunnar Senum and Stephen are three thermal eddies, about 250 meters wide, in the boundary layer. These thermal eddies are formed from the solar heating of the surface and help to form the boundary layer. The eddy updrafts are transporting
MULTI-DOMAIN INDUSTRIAL BENCHMARKS FOR EDDY CURRENT MODELING: THE COFREND WORKING GROUP
Paris-Sud XI, Université de
Conference on Non-Destructive Testing (ECNDT 2010), Moscou : France (2010)" #12;Concerning eddy currents
On the role of mesoscale eddies in the ventilation of Antarctic intermediate water
Fischlin, Andreas
On the role of mesoscale eddies in the ventilation of Antarctic intermediate water Zouhair Lachkar Mesoscale eddies CFC-11 Ventilation Southern Ocean a b s t r a c t The spatial distribution of Antarctic and ventilation are substantially affected by mesoscale eddies. To diagnose the role of eddies, we made global CFC
Qiu, Bo
Seasonal Mesoscale and Submesoscale Eddy Variability along the North Pacific Subtropical abundant in mesoscale eddies, but also exhibits prominent submesoscale eddy features. Output from a 1 the seasonal STCC variability in the mesoscale versus submesoscale ranges. Resolving the eddy scales of .150 km
Eddy heat fluxes at Drake Passage due to mesoscale motions
Rojas Recabal, Ricardo Luis
1982-01-01T23:59:59.000Z
EDDY HEAT FLUKES AT DRAKE PASSAGE DUE TO MESOSCALE MOTIONS A Thesis by RICARDO LUIS ROJAS RECABAL Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE May... 1982 Major Subject: Oceanography EDDY HEAT FLUXES AT DRAKE PASSAGE DUE TO MESOSCALE NOTIONS A Thesis by RICARDO LUIS ROJAS RECABAL Approved as to style and content by: was )W-~ Member em er May 1982 ABSTRACT Eddy Heat Fluxes at Drake Passage...
Pradipta, Rezy
2012-01-01T23:59:59.000Z
In this thesis, we investigate the potential role played by large-scale anomalous heat sources (e.g. prolonged heat wave events) in generating acoustic-gravity waves (AGWs) that might trigger widespread plasma turbulence ...
Eddy-current-damped microelectromechanical switch
Christenson, Todd R. (Albuquerque, NM); Polosky, Marc A. (Tijeras, NM)
2009-12-15T23:59:59.000Z
A microelectromechanical (MEM) device is disclosed that includes a shuttle suspended for movement above a substrate. A plurality of permanent magnets in the shuttle of the MEM device interact with a metal plate which forms the substrate or a metal portion thereof to provide an eddy-current damping of the shuttle, thereby making the shuttle responsive to changes in acceleration or velocity of the MEM device. Alternately, the permanent magnets can be located in the substrate, and the metal portion can form the shuttle. An electrical switch closure in the MEM device can occur in response to a predetermined acceleration-time event. The MEM device, which can be fabricated either by micromachining or LIGA, can be used for sensing an acceleration or deceleration event (e.g. in automotive applications such as airbag deployment or seat belt retraction).
Eddy-current-damped microelectromechanical switch
Christenson, Todd R. (Albuquerque, NM); Polosky, Marc A. (Tijeras, NM)
2007-10-30T23:59:59.000Z
A microelectromechanical (MEM) device is disclosed that includes a shuttle suspended for movement above a substrate. A plurality of permanent magnets in the shuttle of the MEM device interact with a metal plate which forms the substrate or a metal portion thereof to provide an eddy-current damping of the shuttle, thereby making the shuttle responsive to changes in acceleration or velocity of the MEM device. Alternately, the permanent magnets can be located in the substrate, and the metal portion can form the shuttle. An electrical switch closure in the MEM device can occur in response to a predetermined acceleration-time event. The MEM device, which can be fabricated either by micromachining or LIGA, can be used for sensing an acceleration or deceleration event (e.g. in automotive applications such as airbag deployment or seat belt retraction).
An eddy closure for potential vorticity
Ringler, Todd D [Los Alamos National Laboratory
2009-01-01T23:59:59.000Z
The Gent-McWilliams (GM) parameterization is extended to include a direct influence in the momentum equation. The extension is carried out in two stages; an analysis of the inviscid system is followed by an analysis of the viscous system. In the inviscid analysis the momentum equation is modified such that potential vorticity is conserved along particle trajectories following a transport velocity that includes the Bolus velocity in a manner exactly analogous to the continuity and tracer equations. In addition (and in contrast to traditional GM closures), the new formulation of the inviscid momentum equation results in a conservative exchange between potential and kinetic forms of energy. The inviscid form of the eddy closure conserves total energy to within an error proportional to the time derivative of the Bolus velocity. The hypothesis that the viscous term in the momentum equation should give rise to potential vorticity being diffused along isopycnals in a manner analogous to other tracers is examined in detail. While the form of the momentum closure that follows from a strict adherence to this hypothesis is not immediately interpretable within the constructs of traditional momentum closures, three approximations to this hypothesis results in a form of dissipation that is consistent with traditional Laplacian diffusion. The first two approximations are that relative vorticity, not potential vorticity, is diffused along isopyncals and that the flow is in approximate geostrophic balance. An additional approximation to the Jacobian term is required when the dissipation coefficient varies in space. More importantly, the critique of this hypothesis results in the conclusion that the viscosity parameter in the momentum equation should be identical to the tradition GM closure parameter {Kappa}. Overall, we deem the viscous form of the eddy closure for potential vorticity as a viable closure for use in ocean circulation models.
Wang, Liang; Stinson, Gregory S; Macciò, Andrea V; Penzo, Camilla; Kang, Xi; Keller, Ben W; Wadsley, James
2015-01-01T23:59:59.000Z
We introduce project NIHAO (Numerical Investigation of a Hundred Astrophysical Objects), a set of 100 cosmological zoom-in hydrodynamical simulations performed using the GASOLINE code, with an improved implementation of the SPH algorithm. The haloes in our study range from dwarf to Milky Way masses, and represent an unbiased sampling of merger histories, concentrations and spin parameters. The particle masses and force softenings are chosen to resolve the mass profile to below 1% of the virial radius at all masses, ensuring that galaxy half-light radii are well resolved. Using the same treatment of star formation and stellar feedback for every object, the simulated galaxies reproduce the observed inefficiency of galaxy formation across cosmic time as expressed through the stellar mass vs halo mass relation, and the star formation rate vs stellar mass relation. We thus conclude that stellar feedback is the chief piece of physics required to limit the efficiency of star formation in galaxies less massive than t...
Eddy sensors for small diameter stainless steel tubes.
Skinner, Jack L.; Morales, Alfredo Martin; Grant, J. Brian; Korellis, Henry James; LaFord, Marianne Elizabeth; Van Blarigan, Benjamin; Andersen, Lisa E.
2011-08-01T23:59:59.000Z
The goal of this project was to develop non-destructive, minimally disruptive eddy sensors to inspect small diameter stainless steel metal tubes. Modifications to Sandia's Emphasis/EIGER code allowed for the modeling of eddy current bobbin sensors near or around 1/8-inch outer diameter stainless steel tubing. Modeling results indicated that an eddy sensor based on a single axial coil could effectively detect changes in the inner diameter of a stainless steel tubing. Based on the modeling results, sensor coils capable of detecting small changes in the inner diameter of a stainless steel tube were designed, built and tested. The observed sensor response agreed with the results of the modeling and with eddy sensor theory. A separate limited distribution SAND report is being issued demonstrating the application of this sensor.
Mesoscale Eddies in the Gulf of Alaska: Observations and Implications
Rovegno, Peter
2012-01-01T23:59:59.000Z
Chao, Y. 2012. Modeling the mesoscale eddy field in the GulfShriver, J. F. 2001. Mesoscale variability in the boundaryof the Gulf of Alaska mesoscale circulation. Progress in
Eddy-mean flow interactions in western boundary current jets
Waterman, Stephanie N
2009-01-01T23:59:59.000Z
This thesis examines the nature of eddy-mean flow interactions in western boundary current jets and recirculation gyre dynamics from both theoretical and observational perspectives. It includes theoretical studies of ...
Analysis of azimuthal mode dynamics of mesoscale eddies
McCalpin, John David
1984-01-01T23:59:59.000Z
ANALYSIS OF AZIMUTHAL MODE DYNAMICS OF MESOSCALE EDDIES A Thesis by UOHN DAVID MCCALPIN Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1984... Major Subject: Oceanography ANALYSIS OF AZIMUTHAL MODE DYNAMICS OF MESOSCALE EDDIES A Thesis by JOHN DAVID MCCALPIN Approved as to style and content by: rew . as ano (Chairman of Committee) o ert . ei (Member) uy . rancesc &ni (Member) Robert...
Elmroth, Erik
A Parallel Implementation of the TOUGH2 Software Package for Large Scale Multiphase Fluid and Heat groundwater flow related problems such as nuclear waste isolation, environmental remediation, and geothermal with ¢¡¤£¦¥§ ¨¡© blocks in a Yucca Mountain nuclear waste site study. Keywords. Ground water flow, grid partitioning
Elmroth, Erik
A Parallel Implementation of the TOUGH2 Software Package for Large Scale Multiphase Fluid and Heat groundwater flow related problems such as nuclear waste isolation, environmental remediation, and geothermal 6 blocks in a Yucca Mountain nuclear waste site study. Keywords. Ground water flow, grid
Ku?el, Petr
, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia Division of Chemical Physics, Lund University frequencies is thermally activated but with a much smaller activation energy compared to the dc case, the dc transport is thermally activated with activation energies which can be as large as 350 me
Maury Cuna, H; Zimmermann, F
2012-01-01T23:59:59.000Z
The heat load generated by an electron cloud in the cold arcs of the Large Hadron Collider (LHC) is a concern for operation near and beyond nominal beam current. We report the results of simulation studies, with updated secondary- emission models, which examine the severity of the electron heat load over a range of possible operation parameters, both for the nominal LHC and for various luminosity-upgrade scenarios, such as the so-called ‘‘full crab crossing’’ and ‘‘early separation’’ schemes, the ‘‘large Piwinski angle’’ scheme, and a variant of the latter providing ‘‘compatibility’’ with the (upgraded) LHCb experiment. The variable parameters considered are the maximum secondary-emission yield, the number of particles per bunch, and the spacing between bunches. In addition, the dependence of the heat load on the longitudinal bunch profile is investigated.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrinceton PlasmaAfternoon4.CCSM4large.jpgbriefingUses ofUsing
Nagy, Peter B.
Journal of Nondestructive Evaluation, Vol. 23, No. 3, September 2004 ( C 2004) Eddy Current in eddy current conductivity at increasing inspection frequencies, which can be exploited components, lend themselves easily for eddy current residual stress assessment lies in their favorable
Mahinthakumar, K.
1997-01-01T23:59:59.000Z
In this report we present parallel solvers for large linear systems arising from the finite-element discretization of the three-dimensional steady-state groundwater flow problem. Our solvers are based on multigrid and Krylov subspace methods. The parallel implementation is based on a domain decomposition strategy with explicit message passing using NX and MPI libraries. We have tested our parallel implementations on the Intel Paragon XP/S 150 supercomputer using up to 1024 parallel processors and on other parallel platforms such as SGI/Power Challenge Array, Cray/SGI Origin 2000, Convex Exemplar SPP-1200, and IBM SP using up to 64 processors. We show that multigrid can be a scalable algorithm on distributed memory machines. We demonstrate the effectiveness of parallel multigrid based solvers by solving problems requiring more than 70 million nodes in less than a minute. This is more than 25 times faster than the diagonal preconditioned conjugate gradient method which is one of the more popular methods for large sparse linear systems. Our results also show that multigrid as a stand alone solver works best for problems with smooth coefficients, but for rough coefficients it is best used as a preconditioner for a Krylov subspace method such as the conjugate gradient method. We show that even for extremely heterogeneous systems the multigrid pre-conditioned conjugate gradient method is at least 10 times faster than the diagonally preconditioned conjugate gradient method.
CgWind: A high-order accurate simulation tool for wind turbines and wind farms
Chand, K K; Henshaw, W D; Lundquist, K A; Singer, M A
2010-02-22T23:59:59.000Z
CgWind is a high-fidelity large eddy simulation (LES) tool designed to meet the modeling needs of wind turbine and wind park engineers. This tool combines several advanced computational technologies in order to model accurately the complex and dynamic nature of wind energy applications. The composite grid approach provides high-quality structured grids for the efficient implementation of high-order accurate discretizations of the incompressible Navier-Stokes equations. Composite grids also provide a natural mechanism for modeling bodies in relative motion and complex geometry. Advanced algorithms such as matrix-free multigrid, compact discretizations and approximate factorization will allow CgWind to perform highly resolved calculations efficiently on a wide class of computing resources. Also in development are nonlinear LES subgrid-scale models required to simulate the many interacting scales present in large wind turbine applications. This paper outlines our approach, the current status of CgWind and future development plans.
On the simulation of shock-driven material mixing in high-Re flows (u)
Grinstein, Fernando F [Los Alamos National Laboratory
2009-01-01T23:59:59.000Z
Implicit large eddy simulation proposes to effectively rely on the use of subgrid modeling and filtering provided implicitly by physics capturing numerics. Extensive work has demonstrated that predictive simulations of turbulent velocity fields are possible using a class of high resolution, non-oscillatory finite-volume (NFV) numerical algorithms. Truncation terms associated with NFV methods implicitly provide subgrid models capable of emulating the physical dynamics of the unresolved turbulent velocity fluctuations by themselves. The extension of the approach to the substantially more difficult problem of under-resolved material mixing by an under-resolved velocity field has not yet been investigated numerically, nor are there any theories as to when the methodology may be expected to be successful. Progress in addressing these issues in studies of shock-driven scalar mixing driven by Ritchmyer-Meshkov instabilities will be reported in the context of ongoing simulations of shock-tube laboratory experiments.
Sreepathi, Sarat [ORNL] [ORNL; Sripathi, Vamsi [Intel Corporation] [Intel Corporation; Mills, Richard T [ORNL] [ORNL; Hammond, Glenn [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Mahinthakumar, Kumar [North Carolina State University] [North Carolina State University
2013-01-01T23:59:59.000Z
Inefficient parallel I/O is known to be a major bottleneck among scientific applications employed on supercomputers as the number of processor cores grows into the thousands. Our prior experience indicated that parallel I/O libraries such as HDF5 that rely on MPI-IO do not scale well beyond 10K processor cores, especially on parallel file systems (like Lustre) with single point of resource contention. Our previous optimization efforts for a massively parallel multi-phase and multi-component subsurface simulator (PFLOTRAN) led to a two-phase I/O approach at the application level where a set of designated processes participate in the I/O process by splitting the I/O operation into a communication phase and a disk I/O phase. The designated I/O processes are created by splitting the MPI global communicator into multiple sub-communicators. The root process in each sub-communicator is responsible for performing the I/O operations for the entire group and then distributing the data to rest of the group. This approach resulted in over 25X speedup in HDF I/O read performance and 3X speedup in write performance for PFLOTRAN at over 100K processor cores on the ORNL Jaguar supercomputer. This research describes the design and development of a general purpose parallel I/O library, SCORPIO (SCalable block-ORiented Parallel I/O) that incorporates our optimized two-phase I/O approach. The library provides a simplified higher level abstraction to the user, sitting atop existing parallel I/O libraries (such as HDF5) and implements optimized I/O access patterns that can scale on larger number of processors. Performance results with standard benchmark problems and PFLOTRAN indicate that our library is able to maintain the same speedups as before with the added flexibility of being applicable to a wider range of I/O intensive applications.
METAMODELS AS INPUT OF AN OPTIMIZATION ALGORITHM FOR SOLVING AN INVERSE EDDY CURRENT TESTING PROBLEM
Boyer, Edmond
METAMODELS AS INPUT OF AN OPTIMIZATION ALGORITHM FOR SOLVING AN INVERSE EDDY CURRENT TESTING-Curie, 91192 Gif-sur-Yvette, France Abstract A new mean of solution of eddy current testing (ECT) inverse
Mixed Layer Lateral Eddy Fluxes Mediated by Air-Sea Interaction
Shuckburgh, Emily
The modulation of air–sea heat fluxes by geostrophic eddies due to the stirring of temperature at the sea surface is discussed and quantified. It is argued that the damping of eddy temperature variance by such air–sea ...
Bates, Michael
Observations and theory suggest that lateral mixing by mesoscale ocean eddies only reaches its maximum potential at steering levels, surfaces at which the propagation speed of eddies approaches that of the mean flow. Away ...
Energy pathways and structures of oceanic eddies from the ECCO2 State Estimate and Simplified Models
Chen, Ru, Ph. D. Massachusetts Institute of Technology
2013-01-01T23:59:59.000Z
Studying oceanic eddies is important for understanding and predicting ocean circulation and climate variability. The central focus of this dissertation is the energy exchange between eddies and mean ow and banded structures ...
Ching, Wai-Yim
2014-12-31T23:59:59.000Z
Advanced materials with applications in extreme conditions such as high temperature, high pressure, and corrosive environments play a critical role in the development of new technologies to significantly improve the performance of different types of power plants. Materials that are currently employed in fossil energy conversion systems are typically the Ni-based alloys and stainless steels that have already reached their ultimate performance limits. Incremental improvements are unlikely to meet the more stringent requirements aimed at increased efficiency and reduce risks while addressing environmental concerns and keeping costs low. Computational studies can lead the way in the search for novel materials or for significant improvements in existing materials that can meet such requirements. Detailed computational studies with sufficient predictive power can provide an atomistic level understanding of the key characteristics that lead to desirable properties. This project focuses on the comprehensive study of a new class of materials called MAX phases, or Mn+1AXn (M = a transition metal, A = Al or other group III, IV, and V elements, X = C or N). The MAX phases are layered transition metal carbides or nitrides with a rare combination of metallic and ceramic properties. Due to their unique structural arrangements and special types of bonding, these thermodynamically stable alloys possess some of the most outstanding properties. We used a genomic approach in screening a large number of potential MAX phases and established a database for 665 viable MAX compounds on the structure, mechanical and electronic properties and investigated the correlations between them. This database if then used as a tool for materials informatics for further exploration of this class of intermetallic compounds.
Eddy Current Testing for Detecting Small Defects in Thin Films
Obeid, Simon; Tranjan, Farid M. [Electrical and Computer Engineering Department, UNCC (United States); Dogaru, Teodor [Albany Instruments, 426-O Barton Creek, Charlotte, NC 28262 (United States)
2007-03-21T23:59:59.000Z
Presented here is a technique of using Eddy Current based Giant Magneto-Resistance sensor (GMR) to detect surface and sub-layered minute defects in thin films. For surface crack detection, a measurement was performed on a copper metallization of 5-10 microns thick. It was done by scanning the GMR sensor on the surface of the wafer that had two scratches of 0.2 mm, and 2.5 mm in length respectively. In another experiment, metal coatings were deposited over the layers containing five defects with known lengths such that the defects were invisible from the surface. The limit of detection (resolution), in terms of defect size, of the GMR high-resolution Eddy Current probe was studied using this sample. Applications of Eddy Current testing include detecting defects in thin film metallic layers, and quality control of metallization layers on silicon wafers for integrated circuits manufacturing.
Optimisation of an idealised ocean model, stochastic parameterisation of sub-grid eddies
Fenwick C. Cooper; Laure Zanna
2014-10-21T23:59:59.000Z
An optimisation scheme is developed to accurately represent the sub-grid scale forcing of a high dimensional chaotic ocean system. Using a simple parameterisation scheme, the velocity components of a 30km resolution shallow water ocean model are optimised to have the same climatological mean and variance as that of a less viscous 7.5km resolution model. The 5 day lag-covariance is also optimised, leading to a more accurate estimate of the high resolution response to forcing using the low resolution model. The system considered is an idealised barotropic double gyre that is chaotic at both resolutions. Using the optimisation scheme, we find and apply the constant in time, but spatially varying, forcing term that is equal to the time integrated forcing of the sub-mesoscale eddies. A linear stochastic term, independent of the large-scale flow, with no spatial correlation but a spatially varying amplitude and time scale is used to represent the transient eddies. The climatological mean, variance and 5 day lag-covariance of the velocity from a single high resolution integration is used to provide an optimisation target. No other high resolution statistics are required. Additional programming effort, for example to build a tangent linear or adjoint model, is not required either. The focus of this paper is on the optimisation scheme and the accuracy of the optimised flow. The method can be applied in future investigations into the physical processes that govern barotropic turbulence and it can perhaps be applied to help understand and correct biases in the mean and variance of a more realistic coarse or eddy-permitting ocean model. The method is complementary to current parameterisations and can be applied at the same time without modification.
Wadley, Haydn
Modeling multifrequency eddy current sensor interactions during vertical Bridgman growth methods have been used to analyze the responses of two ``absolute'' and ``differential'' eddy current conductivity ratio increases. Of the materials studied, GaAs is found best suited for eddy current sensing
An H-Formulation for the Three-Dimensional Eddy Current Problem in Laminated Structures
Zheng, Weiying
An H- Formulation for the Three-Dimensional Eddy Current Problem in Laminated Structures Peijun Li-dimensional eddy currents in grain-oriented (GO) silicon steel laminations since the coating film is only several to the smallest scale can be up to 106. In this paper, we study an H- formulation for the nonlinear eddy current
EDDY CURRENT TESTING OF FERROMAGNETIC MATERIALS: MODELLING OF MULTIPLE FLAWS IN A
Paris-Sud XI, Université de
EDDY CURRENT TESTING OF FERROMAGNETIC MATERIALS: MODELLING OF MULTIPLE FLAWS IN A PLANAR STRATIFIED Université Paris Sud 11), 3, rue Joliot-Curie, 91192 Gif-sur- Yvette, France ! "#$%&'(%! Eddy current testing. Lambert, H. Voillaume and N. Dominguez, "A 3D model for eddy current inspection in aeronautics
AN ADAPTIVE FINITE ELEMENT METHOD FOR THE EDDY CURRENT MODEL WITH CIRCUIT/FIELD COUPLINGS
AN ADAPTIVE FINITE ELEMENT METHOD FOR THE EDDY CURRENT MODEL WITH CIRCUIT/FIELD COUPLINGS JUNQING for solving the eddy current model with voltage excitations for complicated three dimensional structures of the proposed method. Key words. Eddy current, circuit/field coupling, adaptivity, a posteriori error analysis
IEEE TRANS. MAGN., SUBMITTED 1 3D Eddy-Current Imaging of Metal Tubes by
Paris-Sud XI, Université de
IEEE TRANS. MAGN., SUBMITTED 1 3D Eddy-Current Imaging of Metal Tubes by Gradient-Based, Controlled, and Oliver Dorn Abstract--Eddy-current non-destructive testing is widely used to detect defects within-developed binary-specialized method. Index Terms--eddy-current non-destructive testing, impedance variations, level
A generalized likelihood ratio technique for automated analysis of bobbin coil eddy current dataq
Polikar, Robi
A generalized likelihood ratio technique for automated analysis of bobbin coil eddy current dataq M signals that are commonly found in bobbin coil eddy current data. The performance of the proposed for automated processing and classi®cation of eddy current data. q 2002 Elsevier Science Ltd. All rights
EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES Study on the eddy current damping of the spin dynamics of
Paris-Sud XI, Université de
4TH EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES Study on the eddy current damping of the spin consideration in this article, are impacted by torques generated by eddy currents as the conducting non, the permanent magnetic field from the magnetosphere generates eddy current in the spinning, conducting body
2258 IEEE TRANSACTIONS ON MAGNETICS, VOL. 33, NO. 3, MAY 1997 Pulsed Eddy-Current Response
Bowler, John R.
2258 IEEE TRANSACTIONS ON MAGNETICS, VOL. 33, NO. 3, MAY 1997 Pulsed Eddy-Current Response to a Conducting Half-Space John Bowler, Member, IEEE, and Marcus Johnson Abstract-- Eddy-current nondestructive agreement between theory and experiment. Index Terms--Eddy current, half-space, pulsed, transient. I
Low-frequency perturbation theory in eddy-current non-destructive evaluation
Bowler, John R.
Low-frequency perturbation theory in eddy-current non-destructive evaluation N. Harfield,a) Y series solutions for the impedance change in an eddy-current test probe due to closed cracks in a non structures in, for example, the nuclear power and aero- space industries. Eddy-current inspection methods
NUMERICAL TREATMENT OF REALISTIC BOUNDARY CONDITIONS FOR THE EDDY CURRENT PROBLEM IN AN
RodrÃguez, Rodolfo
NUMERICAL TREATMENT OF REALISTIC BOUNDARY CONDITIONS FOR THE EDDY CURRENT PROBLEM IN AN ELECTRODE methods to solve the eddy current problem in a conducting bounded domain. In particular, we consider-frequency harmonic Maxwell equations, eddy current problems, finite element computational electromagnetism, Lagrange
MATHEMATICAL AND NUMERICAL ANALYSIS OF A TRANSIENT EDDY CURRENT AXISYMMETRIC PROBLEM
RodrÃguez, Rodolfo
MATHEMATICAL AND NUMERICAL ANALYSIS OF A TRANSIENT EDDY CURRENT AXISYMMETRIC PROBLEM INVOLVING to solve a tran- sient eddy current axisymmetric problem. We consider the case of a coil supplied with a source current generating a magnetic field which induces eddy currents in a nearby workpiece
Fitzpatrick, Richard
Observation of tearing mode deceleration and locking due to eddy currents induced in a conducting eddy currents induced by the rotating mode in the conducting shell surrounding the plasma. According to the amplitude of the mode.47 According to this theory, eddy currents induced in the conducting shell
Singularities of eddy current problems Martin Costabel, Monique Dauge, Serge Nicaise
Singularities of eddy current problems Martin Costabel, Monique Dauge, Serge Nicaise May 13, 2003 Abstract We consider the time-harmonic eddy current problem in its electric formulation where the conductor60. 1 Maxwell equations and the eddy current limit Let us consider the model case of an homogeneous
Eddy currents in a gradient coil, modelled as circular loops of strips
Eindhoven, Technische Universiteit
Eddy currents in a gradient coil, modelled as circular loops of strips J.M.B. Kroot, S.J.L. van. Due to induction eddy currents occur which lead to the so-called edge-effect. The edge- effect depends the gradient coils themselves. Eddy currents occur, causing perturbations on the expected gradient field
Anisotropic grain noise in eddy current inspection of noncubic polycrystalline metals
Nagy, Peter B.
Anisotropic grain noise in eddy current inspection of noncubic polycrystalline metals Mark Blodgett of microstructural noise. In eddy current inspection of noncubic crystallographic classes of polycrystalline metals the electrical grain noise is clearly detrimental in eddy current nondestructive testing for small flaws, it can
PROOF COPY 018405PHP Observation of tearing mode deceleration and locking due to eddy currents
Fitzpatrick, Richard
to eddy currents induced in a conducting shell B. E. Chapman Department of Physics, University 6, 3878 1999 in which a braking torque originates from eddy currents induced by the rotating mode, eddy currents induced in the conducting shell surrounding the plasma exert a braking torque
AN E-BASED MIXED FORMULATION FOR A TIME-DEPENDENT EDDY CURRENT PROBLEM
RodrÃguez, Rodolfo
AN E-BASED MIXED FORMULATION FOR A TIME-DEPENDENT EDDY CURRENT PROBLEM RAMIRO ACEVEDO, SALIM-quasistatic submodel usually called eddy current problem; see for instance [9, Chapter 8]. From the mathematical point this harmonic behavior, leading to the so-called time-harmonic eddy current problem. However, even in the case
Eddy current coil interaction with a right-angled conductive wedge
Bowler, John R.
Eddy current coil interaction with a right-angled conductive wedge BY T. P. THEODOULIDIS 1 AND J. R: eddy current; conductive wedge; coil impedance 1. Introduction The quasi-static electromagnetic field whose axis is normal to one of the wedge faces. The problem has applications in eddy current non
Calculation of eddy currents in moving structures by a sliding mesh-nite element method
Buffa, Annalisa
Calculation of eddy currents in moving structures by a sliding mesh- nite element method A. Bu of eddy currents in non-stationary structures. Both 2D and 3D models are considered. The approximation. An implicit Euler scheme is used to discretize in time. Key words { eddy currents, nite element approxima
Time domain half-space dyadic Green's functions for eddy-current calculations
Bowler, John R.
Time domain half-space dyadic Green's functions for eddy-current calculations J. R. Bowlera) Centre American Institute of Physics. S0021-8979 99 08422-4 I. TIME DOMAIN INTERACTION The calculation of eddy-current-domain eddy-current scattering problems for cases in which a scat- terer is embedded in an otherwise
Analysis of eddy currents in a gradient coil J.M.B. Kroot
Eindhoven, Technische Universiteit
Analysis of eddy currents in a gradient coil J.M.B. Kroot Eindhoven University of Technology P in the tangential direction as well, due to eddy currents induced by other coils. In order to take the dependence, and the frequency is low enough to allow for a quasistatic approximation. Due to induction eddy currents occur
Analysis of eddy currents in a gradient coil J.M.B. Kroot
Eindhoven, Technische Universiteit
Analysis of eddy currents in a gradient coil J.M.B. Kroot Eindhoven University of Technology P in the tangential direction as well, due to eddy currents induced by other coils. In order to take the dependence, and the frequency is low enough to allow for a quasi-static approximation. Due to induction eddy currents occur
Analytical Model of Magnet Eddy-Current Volume Losses in Multi-phase PM Machines
Paris-Sud XI, Université de
Analytical Model of Magnet Eddy-Current Volume Losses in Multi-phase PM Machines with Concentrated, 94000 Créteil France Abstract--this paper studies magnet eddy-current losses in permanent magnet (PM calculations. Keywords--Traction, Concentrated Winding, Eddy- Current, Volume Magnet Losses, Multiphase Machine
Angular approach combined to mechanical model for tool breakage detection by eddy current sensors
Paris-Sud XI, Université de
1 Angular approach combined to mechanical model for tool breakage detection by eddy current sensors solution is proposed for the estimate of cutting force using eddy current sensors implemented close eccentricity obtained during the machining from the eddy current sensors signals. Efficiency and reliability
Numerical analysis of electric field formulations of the eddy current model
RodrÃguez, Rodolfo
Numerical analysis of electric field formulations of the eddy current model Alfredo BermÂ´udez1 methods for the numeri- cal solution of the eddy current problem in a bounded conducting domain crossed): 78M10, 65N30 Key words Low-frequency harmonic Maxwell equations, eddy currents, finite elements
An eddy current problem related to electromagnetic Alfredo Bermudez, Rafael Mu~noz, Pilar Salgado
RodrÃguez, Rodolfo
An eddy current problem related to electromagnetic forming Alfredo BermÂ´udez, Rafael Mu~noz, Pilar is to analyze a numerical method to solve a transient axisymmetric eddy current problem arising from currents in the workpiece. The magnetic field, together with the eddy currents, originate the Lorentz
Nagy, Peter B.
2007-01-01T23:59:59.000Z
NDT&E International 40 (2007) 405418 High-frequency eddy current conductivity spectroscopy Available online 11 February 2007 Abstract Recent research results indicated that eddy current conductivity-conductivity engine alloys the eddy current penetration depth could not be forced below 0.2 mm without expanding
AN ADAPTIVE FINITE ELEMENT METHOD FOR THE H -FORMULATION OF TIME-DEPENDENT EDDY CURRENT
AN ADAPTIVE FINITE ELEMENT METHOD FOR THE H - FORMULATION OF TIME-DEPENDENT EDDY CURRENT PROBLEMS, eddy current problem, adaptive finite element method, mul- tiply connected conductor, Team Workshop Problem 7 AMS subject classifications. 65M60, 65M50, 78A25 1. Introduction. Eddy currents appear in almost
Eddy-current interaction with an ideal crack. II. The inverse problem John FL Bowler
Bowler, John R.
Eddy-current interaction with an ideal crack. II. The inverse problem John FL Bowler The University 1994) Eddy-current inversion is the process whereby the geometry of a flaw in a metal is derived from eddy-current probe impedance measurements. The approach is based on an optimization scheme that seeks
STABILIZATION OF KINK INSTABILITIES BY EDDY CURRENTS IN A SEGMENTED WALL AND
Mauel, Michael E.
STABILIZATION OF KINK INSTABILITIES BY EDDY CURRENTS IN A SEGMENTED WALL AND COMPARISON WITH IDEAL and measured equi- librium wall eddy currents. The stability analysis of these equilibria predicts patterns of instability induced eddy currents for a model wall that is continuous and perfectly conducting
Near-Surface Eddy Heat and Momentum Fluxes in the Antarctic Circumpolar Current in Drake Passage
Sprintall, Janet
Near-Surface Eddy Heat and Momentum Fluxes in the Antarctic Circumpolar Current in Drake Passage Antarctic Circumpolar Current (ACC) momentum balance. The observations span 7 yr and are compared to eddy Current (ACC) pathway is marked by exceptionally high mesoscale eddy activity (e.g., Stammer 1998; Hughes
Simplified High-Accuracy Calculation of Eddy-Current Losses in Round-Wire Windings
Simplified High-Accuracy Calculation of Eddy-Current Losses in Round-Wire Windings Xi Nan C. R the IEEE. #12;Simplified High-Accuracy Calculation of Eddy-Current Loss in Round-Wire Windings Xi Nan-- It has recently been shown that the most commonly used methods for calculating high-frequency eddy-current
Numerical solution of eddy current problems in bounded domains using realistic boundary
RodrÃguez, Rodolfo
Numerical solution of eddy current problems in bounded domains using realistic boundary conditions-called eddy currents. The problem is formulated in terms of the magnetic field. This formulation in a metallurgical arc furnace. Key words: low-frequency harmonic Maxwell equations, eddy current problems, finite
558: Calculation of Eddy Currents in the ETE Spherical Torus G.O. Ludwig
558: Calculation of Eddy Currents in the ETE Spherical Torus G.O. Ludwig Instituto Nacional de model based on the Green's function method. The distribution of eddy currents is calculated using a thin well with values of the eddy currents measured in ETE. INTRODUCTION This paper presents a magnetostatic
Nagy, Peter B.
Numerical method for calculating the apparent eddy current conductivity loss on randomly rough Because of their frequency-dependent penetration depth, eddy current measurements are capable of mapping of eddy current conductivity, thereby decreasing the accuracy of the measurements, especially in thermally
Theory of thin-skin eddy-current interaction with surface cracks N. Harfielda)
Bowler, John R.
Theory of thin-skin eddy-current interaction with surface cracks N. Harfielda) and J. R. Bowler; accepted for publication 14 July 1997 Eddy-current non-destructive evaluation is commonly performed of a typical crack. A thin-skin analysis of eddy currents is presented in which the electromagnetic fields
Mathematical and numerical analysis of a transient non-linear axisymmetric eddy current model
RodrÃguez, Rodolfo
Mathematical and numerical analysis of a transient non-linear axisymmetric eddy current model the theoretically predicted behavior of the method, are reported. Keywords transient eddy current Â· axisymmetric is the accurate computation of power losses in the ferromagnetic components of the core due to hysteresis and eddy-current
Theory of eddy current inversion Stephen:J. Nortona) and John FL Bowler
Bowler, John R.
Theory of eddy current inversion Stephen:J. Nortona) and John FL Bowler University of Surrey) The inverse eddy current problem can be described as the task of reconstructing an unknown distribution of electrical conductivity from eddy-current probe impedance measurements recorded as a function of probe
Eddy-current interaction with an ideal crack. I. The forward problem J. R. Bowler
Bowler, John R.
Eddy-current interaction with an ideal crack. I. The forward problem J. R. Bowler The University February 1994) The impedance of an eddy-current probe changes when the current it induces in an electrical to introduce idealizations about the nature of the flaw. Eddy-current interaction is considered with an ideal
Paris-Sud XI, Université de
for eddy currents Non Destructive Testing and Evaluation FrkddricTHOLLON-Nod BURAIS CEGELY- URA CNRS 829 for cracks detection under installed fasteners in aircraftstructure. I. INTRODUCTION Eddy currents are widely to the eddy current control method : -very smallvariations of sensor response. - many geometrical
DIRECT-DRIVE AND EDDY-CURRENT SEPTUM MAGNETS June 29, 2001
Kemner, Ken
DIRECT-DRIVE AND EDDY-CURRENT SEPTUM MAGNETS S. H. Kim June 29, 2001 Abstract -- Two types of thin septum magnets, direct drive and eddy current, were compared mainly in 2-D magnetic aspects. For the eddy-current type, the leakage fields calculated using OPERA-2d were compared with the calculations
Eddy Current Tomography Using a Binary Markov Mila Nikolova and Ali MohammadDjafari
Nikolova, Mila
Eddy Current Tomography Using a Binary Markov Model Mila Nikolova and Ali Mohammad and notches. The medium is illuminated with a monochromatic electric field; the anomalies induce eddy currents in various fields such as nuclear power plants and aerospace engineering. 1 #12; The objective of eddy
NUMERICAL SOLUTION OF A TRANSIENT NON-LINEAR AXISYMMETRIC EDDY CURRENT MODEL WITH NON-LOCAL
RodrÃguez, Rodolfo
NUMERICAL SOLUTION OF A TRANSIENT NON-LINEAR AXISYMMETRIC EDDY CURRENT MODEL WITH NON@ing-mat.udec.cl This paper deals with an axisymmetric transient eddy current problem in conductive nonlinear magnetic media of the proposed scheme. Keywords: transient eddy current problem; electromagnetic losses; nonlinear magnetic
A simple numerical model of the apparent loss of eddy current conductivity due to surface roughness
Nagy, Peter B.
A simple numerical model of the apparent loss of eddy current conductivity due to surface roughness of eddy current conductivity has been suggested as a possible means to allow the nondestructive evaluation, the path of the eddy current must follow a more tortuous route in the material, which produces a reduction
Improvement of the magnetic core for eddy current losses decreasing in cylindrical linear actuators.
Boyer, Edmond
Improvement of the magnetic core for eddy current losses decreasing in cylindrical linear actuators the power) increases, the iron losses become high [1]. One classical method for reducing the eddy current the eddy current losses in a longitudinal flux multi-rod actuator and to compute improvement. 2 The linear
Efficient Solvers for Nonlinear Time-Periodic Eddy Current F. Bachinger
Schoeberl, Joachim
Efficient Solvers for Nonlinear Time-Periodic Eddy Current Problems F. Bachinger U. Langer J. Sch-periodic eddy current problems, ranging from the description of the nonlinearity to an efficient solution setup, the magnetic field and the thereby generated eddy currents hardly penetrate into conducting
A Diagnostic Suite of Models for the Evaluation of Oceanic Mesoscale Eddy Parameterizations
Fox-Kemper, Baylor
A Diagnostic Suite of Models for the Evaluation of Oceanic Mesoscale Eddy Parameterizations by S. D of Oceanic Mesoscale Eddy Parameterizations written by S. D. Bachman has been approved for the Department and Oceanic Sciences) A Diagnostic Suite of Models for the Evaluation of Oceanic Mesoscale Eddy
Jet Interaction and the Influence of a Minimum Phase Speed Bound on the Propagation of Eddies
Vallis, Geoff
Jet Interaction and the Influence of a Minimum Phase Speed Bound on the Propagation of Eddies and analogs of the midlatitude eddy-driven jet and the subtropical jet is investigated in a barotropic b-plane model. In the model the subtropical jet is generated by a relaxation process and the eddy-driven jet
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Vogelmann, Andrew M.; Fridlind, Ann M.; Toto, Tami; Endo, Satoshi; Lin, Wuyin; Wang, Jian; Feng, Sha; Zhang, Yunyan; Turner, David D.; Liu, Yangang; et al
2015-05-01T23:59:59.000Z
Observation-based modeling case studies of continental boundary layer clouds have been developed to study cloudy boundary layers, aerosol influences upon them, and their representation in cloud- and global-scale models. Three 60-hour case study periods span the temporal evolution of cumulus, stratiform, and drizzling boundary layer cloud systems, representing mixed and transitional states rather than idealized or canonical cases. Based on in-situ measurements from the RACORO field campaign and remote-sensing observations, the cases are designed with a modular configuration to simplify use in large-eddy simulations (LES) and single-column models. Aircraft measurements of aerosol number size distribution are fit to lognormal functionsmore »for concise representation in models. Values of the aerosol hygroscopicity parameter, ?, are derived from observations to be ~0.10, which are lower than the 0.3 typical over continents and suggestive of a large aerosol organic fraction. Ensemble large-scale forcing datasets are derived from the ARM variational analysis, ECMWF forecasts, and a multi-scale data assimilation system. The forcings are assessed through comparison of measured bulk atmospheric and cloud properties to those computed in 'trial' large-eddy simulations, where more efficient run times are enabled through modest reductions in grid resolution and domain size compared to the full-sized LES grid. Simulations capture many of the general features observed, but the state-of-the-art forcings were limited at representing details of cloud onset, and tight gradients and high-resolution transients of importance. Methods for improving the initial conditions and forcings are discussed. The cases developed are available to the general modeling community for studying continental boundary clouds.« less
Vessel eddy current measurement for the National Spherical Torus Experiment
Gates, D.A.; Menard, J.E.; Marsala, R.J. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States)
2004-12-01T23:59:59.000Z
A simple analog circuit that measures the National Spherical Torus Experiment (NSTX) axisymmetric eddy current distribution has been designed and constructed. It is based on simple circuit model of the NSTX vacuum vessel that was calibrated using a special axisymmetric eddy current code which was written so that accuracy was maintained in the vicinity of the current filaments [J. Menard, J. Fusion Tech. (to be published)]. The measurement and the model have been benchmarked against data from numerous vacuum shots and they are in excellent agreement. This is an important measurement that helps give more accurate equilibrium reconstructions.
Nitao, J.J.
1989-11-06T23:59:59.000Z
The TOUGH code developed at Lawrence Berkeley Laboratory (LBL) is being extensively used to numerically simulate the thermal and hydrologic environment around nuclear waste packages in the unsaturated zone for the Yucca Mountain Project. At the Lawrence Livermore National Laboratory (LLNL) we have rewritten approximately 80 percent of the TOUGH code to increase its speed and incorporate new options. The geometry of many problems requires large numbers of computational elements elements in order to realistically model detailed physical phenomena, and, as a result, large amounts of computer time are needed. In order to increase the speed of the code we have incorporated fast linear equation solvers, vectorization of substantial portions of code, improved automatic time stepping, and implementation of table look-up for the steam table properties. These enhancements have increased the speed of the code for typical problems by a factor of 20 on the Cray 2 computer. In addition to the increase in computational efficiency we have added several options: vapor pressure lowering; equivalent continuum treatments of fractures; energy and material volumetric, mass and flux accounting; and Stefan-Boltzmann radiative heat transfer. 5 refs.
Hayward, Vincent
Initial results using Eddy Current Brakes as Fast Turn-on, Programmable Physical Dampers for Haptic Machines McGill University, Montr´eal, Qu´ebec, Canada ABSTRACT We demonstrate the use of eddy current propose an alternate method to create damping in a haptic interface that uses eddy current brakes. 2 EDDY
Rauhut, Holger
686 IEEE TRANSACTIONS ON MAGNETICS, VOL. 44, NO. 6, JUNE 2008 Estimating the Eddy-Current Modeling Zurich, CH-8092 ZÃ¼rich, Switzerland The eddy-current model is an approximation of the full Maxwell delivers a mathematical basis for assessing the scope of the eddy-current model. Index Terms--Eddy current
Paris-Sud XI, Université de
1358 IEEE TRANSACTIONS ON MAGNETICS, VOL. 40, NO. 2, MARCH 2004 Eddy-Current Effects in Circuit Abstract--This paper deals with the modeling of eddy currents generated by arc motion during opening phases in determining eddy currents in splitter plates, the second one is devoted to the calculation of eddy currents
McHenry, Michael E.
The role of eddy currents and nanoparticle size on AC magnetic fieldinduced reflow in solder://jap.aip.org/about/rights_and_permissions #12;The role of eddy currents and nanoparticle size on AC magnetic fieldinduced reflow in solder be derived from eddy current losses in Cu planes in the substrate board. Eddy current heating in Cu sheets
EddyViscosity Time Reversing Waves a Dissipative Environment
Garnier, Josselin
where linear shallow water speed is given o o . The kinematic viscosity denoted parameter ratio been shown [6] nonlinear (inviscid) shallow water waves presÂ ence a random topography and alsoEddyViscosity Time Reversing Waves a Dissipative Environment Josselin Garnier Laboratoire
Bottom Drag, eddy diffusivity, wind work and the power integrals
Young, William R.
Bottom Drag, eddy diffusivity, wind work and the power integrals Bill Young, Andrew Thompson field i.e., the meridional heat flux is pro Moreover, the mechanical energy balance in a statistical Moreover, the mechanical energy balance in a statistically st Appendix A) is U-2 x = | - 2 |2 + hyp
Yang, Qing; Leung, Lai-Yung R.; Rauscher, Sara; Ringler, Todd; Taylor, Mark
2014-05-01T23:59:59.000Z
This study investigates the resolution dependency of precipitation extremes in an aqua-planet framework. Strong resolution dependency of precipitation extremes is seen over both tropics and extra-tropics, and the magnitude of this dependency also varies with dynamical cores. Moisture budget analyses based on aqua-planet simulations with the Community Atmosphere Model (CAM) using the Model for Prediction Across Scales (MPAS) and High Order Method Modeling Environment (HOMME) dynamical cores but the same physics parameterizations suggest that during precipitation extremes moisture supply for surface precipitation is mainly derived from advective moisture convergence. The resolution dependency of precipitation extremes mainly originates from advective moisture transport in the vertical direction. At most vertical levels over the tropics and in the lower atmosphere over the subtropics, the vertical eddy transport of mean moisture field dominates the contribution to precipitation extremes and its resolution dependency. Over the subtropics, the source of moisture, its associated energy, and the resolution dependency during extremes are dominated by eddy transport of eddies moisture at the mid- and upper-troposphere. With both MPAS and HOMME dynamical cores, the resolution dependency of the vertical advective moisture convergence is mainly explained by dynamical changes (related to vertical velocity or omega), although the vertical gradients of moisture act like averaging kernels to determine the sensitivity of the overall resolution dependency to the changes in omega at different vertical levels. The natural reduction of variability with coarser resolution, represented by areal data averaging (aggregation) effect, largely explains the resolution dependency in omega. The thermodynamic changes, which likely result from non-linear feedback in response to the large dynamical changes, are small compared to the overall changes in dynamics (omega). However, after excluding the data aggregation effect in omega, thermodynamic changes become relatively significant in offsetting the effect of dynamics leading to reduce differences between the simulated and aggregated results. Compared to MPAS, the simulated stronger vertical motion with HOMME also results in larger resolution dependency. Compared to the simulation at fine resolution, the vertical motion during extremes is insufficiently resolved/parameterized at the coarser resolution even after accounting for the natural reduction in variability with coarser resolution, and this is more distinct in the simulation with HOMME. To reduce uncertainties in simulated precipitation extremes, future development in cloud parameterizations must address their sensitivity to spatial resolution as well as dynamical cores.
Rossby wave radiation by an eddy on the polar beta-plane
Zhang, Yang
2015-01-01T23:59:59.000Z
Results from the laboratory experiments on the evolution of vortices (eddies) generated in a rotating tank with topographic beta-effect are presented. The surface elevation and velocity fields are measured by the Altimetric Imaging Velocimetry. The experiments are supplemented by shallow water numerical simulations as well as a linear theory which describes the Rossby wave radiation by travelling vortices. The cyclonic vortices observed in the experiments travel to the northwest and continuously radiate Rossby waves. Measurements show that initially axisymmetric vortices develop a dipolar component which enables them to perform translational motion. A pattern of alternating zonal jets to the west of the vortex is created by Rossby waves with approximately zonal crests. Energy spectra of the flows in the wavenumber space indicate that a wavenumber similar to that introduced by Rhines for turbulent flows on the beta-plane can be introduced here. The wavenumber is based on the translational speed of a vortex rat...
Simulating Collisions for Hydrokinetic Turbines
Richmond, Marshall C.; Romero Gomez, Pedro DJ; Rakowski, Cynthia L.
2013-10-01T23:59:59.000Z
Evaluations of blade-strike on an axial-flow Marine Hydrokinetic turbine were conducted using a conventional methodology as well as an alternative modeling approach proposed in the present document. The proposed methodology integrates the following components into a Computa- tional Fluid Dynamics (CFD) model: (i) advanced eddy-resolving flow simulations, (ii) ambient turbulence based on field data, (iii) moving turbine blades in highly transient flows, and (iv) Lagrangian particles to mimic the potential fish pathways. The sensitivity of blade-strike prob- ability to the following conditions was also evaluated: (i) to the turbulent environment, (ii) to fish size and (iii) to mean stream flow velocity. The proposed methodology provided fraction of collisions and offered the capability of analyzing the causal relationships between the flow envi- ronment and resulting strikes on rotating blades. Overall, the conventional methodology largely overestimates the probability of strike, and lacks the ability to produce potential fish and aquatic biota trajectories as they interact with the rotating turbine. By using a set of experimental corre- lations of exposure-response of living fish colliding on moving blades, the occurrence, frequency and intensity of the particle collisions was next used to calculate the survival rate of fish crossing the MHK turbine. This step indicated survival rates always greater than 98%. Although the proposed CFD framework is computationally more expensive, it provides the advantage of evaluating multiple mechanisms of stress and injury of hydrokinetic turbine devices on fish.
Alcian Blue Cartilage Staining Beatrice Jegalian & Eddy M. De Robertis
De Robertis, Eddy M.
Alcian Blue Cartilage Staining Beatrice Jegalian & Eddy M. De Robertis (Cell 71, 901-910, 1992) 1 will require more time) in 0.05% Alcian blue 8GX (Fisher) in 5% acetic acid. 6. Wash embryos in 5% acetic acid Alcian Blue 8 g NaCl 0.05% Alcian blue 8GX .2 g KCl 5% acetic acid 1.44 g Na2HPO4 water .24 g KH2PO4 800
Automated detection and location of indications in eddy current signals
Brudnoy, David M. (Albany, NY); Oppenlander, Jane E. (Burnt Hills, NY); Levy, Arthur J. (Schenectady, NY)
2000-01-01T23:59:59.000Z
A computer implemented information extraction process that locates and identifies eddy current signal features in digital point-ordered signals, signals representing data from inspection of test materials, by enhancing the signal features relative to signal noise, detecting features of the signals, verifying the location of the signal features that can be known in advance, and outputting information about the identity and location of all detected signal features.
Eddy current scanning of niobium for SRF cavities at Fermilab
Boffo, C.; Bauer, P.; Foley, M.; Antoine, C.; Cooper, C.; /Fermilab; Brinkmann, A.; /DESY
2006-08-01T23:59:59.000Z
In the framework of SRF cavity development, Fermilab is creating the infrastructure needed for the characterization of the material used in the cavity fabrication. An important step in the characterization of ''as received'' niobium sheets is eddy current scanning. Eddy current scanning is a non-destructive technique first adopted and further developed by DESY with the purpose of checking the cavity material for subsurface defects and inclusions. Fermilab has received and further upgraded a commercial eddy current scanner previously used for the SNS project. This scanner is now used daily to scan the niobium sheets for the Fermilab third harmonic, the ILC, and the Proton Driver cavities. After optical inspection, more than 400 squares and disks have been scanned and when necessary checked at the optical and electron microscopes, anodized, or measured with profilometers looking for surface imperfections that might limit the performance of the cavities. This paper gives a status report on the scanning results obtained so far, including a discussion of the classification of signals being detected.
Method and apparatus for correcting eddy current signal voltage for temperature effects
Kustra, Thomas A. (N. Huntingdon, PA); Caffarel, Alfred J. (Pittsburgh, PA)
1990-01-01T23:59:59.000Z
An apparatus and method for measuring physical characteristics of an electrically conductive material by the use of eddy-current techniques and compensating measurement errors caused by changes in temperature includes a switching arrangement connected between primary and reference coils of an eddy-current probe which allows the probe to be selectively connected between an eddy current output oscilloscope and a digital ohm-meter for measuring the resistances of the primary and reference coils substantially at the time of eddy current measurement. In this way, changes in resistance due to temperature effects can be completely taken into account in determining the true error in the eddy current measurement. The true error can consequently be converted into an equivalent eddy current measurement correction.
Petrie, T.W.; Kosny, J.; Childs, P.W.
1996-03-01T23:59:59.000Z
A full-scale section of half the top of a single-wide manufactured home has been studied in the Large Scale Climate Simulator (LSCS) at the Oak Ridge National Laboratory. A small roof cavity with little room for insulation at the eaves is often the case with single-wide units and limits practical ways to improve thermal performance. The purpose of the current tests was to obtain steady-state performance data for the roof cavity of the manufactured home test section when the roof cavity was insulated with fiberglass batts, blown-in rock wool insulation or combinations of these insulations and powder-filled evacuated panel (PEP) insulation. Four insulation configurations were tested: (A) a configuration with two layers of nominal R{sub US}-7 h {center_dot} ft{sup 2} {center_dot} F/BTU (R{sub SI}-1.2 m{sup 2} {center_dot} K/W) fiberglass batts; (B) a layer of PEPs and one layer of the fiberglass batts; (C) four layers of the fiberglass batts; and (D) an average 4.1 in. (10.4 cm) thick layer of blown-in rock wool at an average density of 2.4 lb/ft{sup 3} (38 kg/m{sup 3}). Effects of additional sheathing were determined for Configurations B and C. With Configuration D over the ceiling, two layers of expanded polystyrene (EPS) boards, each about the same thickness as the PEPs, were installed over the trusses instead of the roof. Aluminum foils facing the attic and over the top layer of EPS were added. The top layer of EPS was then replaced by PEPs.
Eddy current probe with foil sensor mounted on flexible probe tip and method of use
Viertl, John R. M. (Niskayuna, NY); Lee, Martin K. (Niskayuna, NY)
2001-01-01T23:59:59.000Z
A pair of copper coils are embedded in the foil strip. A first coil of the pair generates an electromagnetic field that induces eddy currents on the surface, and the second coil carries a current influenced by the eddy currents on the surface. The currents in the second coil are analyzed to obtain information on the surface eddy currents. An eddy current probe has a metal housing having a tip that is covered by a flexible conductive foil strip. The foil strip is mounted on a deformable nose at the probe tip so that the strip and coils will conform to the surface to which they are applied.
Direct numerical simulation of turbulent reacting flows
Chen, J.H. [Sandia National Laboratories, Livermore, CA (United States)
1993-12-01T23:59:59.000Z
The development of turbulent combustion models that reflect some of the most important characteristics of turbulent reacting flows requires knowledge about the behavior of key quantities in well defined combustion regimes. In turbulent flames, the coupling between the turbulence and the chemistry is so strong in certain regimes that is is very difficult to isolate the role played by one individual phenomenon. Direct numerical simulation (DNS) is an extremely useful tool to study in detail the turbulence-chemistry interactions in certain well defined regimes. Globally, non-premixed flames are controlled by two limiting cases: the fast chemistry limit, where the turbulent fluctuations. In between these two limits, finite-rate chemical effects are important and the turbulence interacts strongly with the chemical processes. This regime is important because industrial burners operate in regimes in which, locally the flame undergoes extinction, or is at least in some nonequilibrium condition. Furthermore, these nonequilibrium conditions strongly influence the production of pollutants. To quantify the finite-rate chemistry effect, direct numerical simulations are performed to study the interaction between an initially laminar non-premixed flame and a three-dimensional field of homogeneous isotropic decaying turbulence. Emphasis is placed on the dynamics of extinction and on transient effects on the fine scale mixing process. Differential molecular diffusion among species is also examined with this approach, both for nonreacting and reacting situations. To address the problem of large-scale mixing and to examine the effects of mean shear, efforts are underway to perform large eddy simulations of round three-dimensional jets.
INCITE Projects 2012 INCITE Projects
Kemner, Ken
: 4 Million Hours Large-Eddy Simulation of Two-Phase Flow Combustion in Gas Turbines Thierry Poinsot
.org/EducationResources/CommunityCollege/EddyCurrents/Introduction/IntroductiontoET.htm, 2 Calderwood, C & Nelligan, T. Eddy Current Testing. Olympus Corporation,2011.[Online]. Available at: http://www.olympus-ims.com/en/eddycurrenttesting/ , 3 Santandrea. L., & Le Bihan, Y. Using COMSOL-Multiphysics in an Eddy Current Non
Methods of and apparatus for levitating an eddy current probe
Stone, William J. (Kansas City, MO)
1988-05-03T23:59:59.000Z
An eddy current probe is supported against the force of gravity with an air earing while being urged horizontally toward the specimen being examined by a spring and displaced horizontally against the force of the spring pneumatically. The pneumatic displacement is accomplished by flowing air between a plenum chamber fixed with respect to the probe and the surface of the specimen. In this way, the surface of the specimen can be examined without making mechanical contact therewith while precisely controlling the distance at which the probe stands-off from the surface of the specimen.
Eddy current system for inspection of train hollow axles
Chady, Tomasz; Psuj, Grzegorz; Sikora, Ryszard; Kowalczyk, Jacek; Spychalski, Ireneusz [Department of Electrical and Computer Engineering, Faculty of Electrical Engineering, West Pomeranian University of Technology, Szczecin (Poland)
2014-02-18T23:59:59.000Z
The structural integrity of wheelsets used in rolling stock is of great importance to the safety. In this paper, electromagnetic system with an eddy current transducer suitable for the inspection of hollow axles have been presented. The transducer was developed to detect surface braking defects having depth not smaller than 0.5 mm. Ultrasound technique can be utilized to inspect the whole axle, but it is not sufficiently sensitive to shallow defects located close to the surface. Therefore, the electromagnetic technique is proposed to detect surface breaking cracks that cannot be detected by ultrasonic technique.
The Role of Eddy-Tansport in the Thermohaline Circulation
Dr. Paola Cessi
2011-11-17T23:59:59.000Z
Several research themes were developed during the course of this project. (1) Low-frequency oceanic varibility; (2) The role of eddies in the Antarctic Circumpolar Current (ACC) region; (3) Deep stratification and the overturning circulation. The key findings were as follows: (1) The stratification below the main thermocline (at about 500m) is determined in the circumpolar region and then communicated to the enclosed portions of the oceans through the overturning circulation. (2) An Atlantic pole-to-pole overturning circulation can be maintained with very small interior mixing as long as surface buoyancy values are shared between the northern North Atlantic and the ACC region.
Ferrari, Raffaele
of the Antarctic Circumpolar Current, despite enhanced values of eddy kinetic energy. The expression in the core of the Antarctic Circumpolar Current or on its flanks. A simple expression is derived statistics. This novel expression predicts suppression of the cross-jet eddy diffusivity in the core
Extremely short impulse eddy current system for titanium and inconel samples testing
Chady, T.; Frankowski, P. [Faculty of Electrical Engineering, West Pomeranian University of Technology, Sikorskiego 37, 70-313 Szczecin (Poland)
2011-06-23T23:59:59.000Z
This paper presents a new system for eddy current testing. The system enables tests with very short current impulses. Therefore, the frequency spectrum of the excitation signal is very wide. In this paper, a study of eddy current differential transducer for testing titanium element is also presented.
Monsoon surges trigger oceanic eddy formation and propagation in the lee of the Philippine Islands
with eddies that form in the lee of the Cabo Verde and Canary Islands [Chavanne et al., 2002; Sangra et al., 2007]. The Hawaii, Cabo Verde and Canary Islands are located in the trades where winds have typicalMonsoon surges trigger oceanic eddy formation and propagation in the lee of the Philippine Islands
Anticyclonic and cyclonic eddies of subtropical origin in the subantarctic zone south of Africa
Boyer, Edmond
that the meridional propagation of mesoscale eddies at distinct sectors of the Subtropical Front (STF), such as those with this view, Dencausse et al. [2011] recently observed that, due to the intense mesoscale activity interval appears as a preferential pathway for mesoscale structures. Here, indeed, warm eddies
Smith, K. Shafer
Sciences, New York University, New York, New York (Manuscript received 13 April 2006, in final form 17 July of potential vorticity (the source of eddy energy) in the zonal and meridional directions are fundamentally. The resulting flux is orders of magnitude higher than in the cross-jet direction, and thus eddy energies driven
Qiu, Bo
Eddy-Induced Heat Transport in the Subtropical North Pacific from Argo, TMI, and Altimetry transport induced by mesoscale oceanic eddies is estimated by combining satellite- derived sea surface temperaturesalinity data. In the North Pacific Ocean subtropical gyre, warm (cold) temperature anomalies
Mesoscale eddies northeast of the Hawaiian archipelago from satellite altimeter observations
Qiu, Bo
Mesoscale eddies northeast of the Hawaiian archipelago from satellite altimeter observations; published 16 March 2010. [1] Enhanced mesoscale eddy activity northeast of the Hawaiian archipelago by 5° longitude subregions revealed the dominant mesoscale periods ranging from 90 days near 18°N
Mesoscale eddies in the northeastern Pacific tropical-subtropical transition zone: Statistical February 2012; revised 24 August 2012; accepted 6 September 2012; published 24 October 2012. [1] Mesoscale cycle. Although mesoscale eddies in these areas have been previously reported, this study provides
RodrÃguez, Rodolfo
Analysis of a FEM-BEM model posed on the conducting domain for the time-dependent eddy currentÂ´atica, Universidad de ConcepciÂ´on, Casilla 160-C, Concepcion, Chile. Abstract The three-dimensional eddy current time. Keywords: Boundary elements; eddy current problem; finite elements; time-dependent electromagnetic problem
ANALYSIS OF THE A, V -A -POTENTIAL FORMULATION FOR THE EDDY CURRENT PROBLEM IN A BOUNDED DOMAIN.
RodrÃguez, Rodolfo
ANALYSIS OF THE A, V - A - POTENTIAL FORMULATION FOR THE EDDY CURRENT PROBLEM IN A BOUNDED DOMAIN analysis of the well-known A, V - A- potential formulation for the eddy current problem. The resulting on standard nodal finite elements. Key words. eddy currents, potential formulation, well-posedness, finite
Page 1 of 31 Why does the Loop Current tend to shed more eddies in summer and winter?1
Page 1 of 31 Why does the Loop Current tend to shed more eddies in summer and winter?1 Y.-L. Chang seasonal preferences of Loop Current eddy shedding, more in summer and5 winter and less in fall and spring in virtually any21 month of the year. That the Loop Current can intrude into the Gulf and eddies can separate
Nagy, Peter B.
2006-01-01T23:59:59.000Z
NDT&E International 39 (2006) 641651 Iterative inversion method for eddy current profiling of near-dependent penetration depth, eddy current measurements are capable of mapping the near-surface depth profile-independent intrinsic electric conductivity depth profile from the frequency-dependent apparent eddy current
Bowler, John R.
IEEE TRANSACTIONS ON MAGNETICS, VOL. 36, NO. 1, JANUARY 2000 281 Thin-Skin Eddy-Current Interaction with Semielliptical and Epicyclic Cracks J. R. Bowler, Member, IEEE, and N. Harfield Abstract--Eddy-current probe current, nondestructive evaluation. I. INTRODUCTION IN EDDY-CURRENT nondestructive evaluation, cracks
RodrÃguez, Rodolfo
Numerical analysis of a finite element method for the axisymmetric eddy current model, 27002, Lugo, Spain The aim of this paper is to analyze a finite element method to solve an eddy current of the method are reported. Keywords: low-frequency harmonic Maxwell equations, eddy current problems, finite
Bowler, John R.
IEEE TRANSACTIONS ON MAGNETICS, VOL. 41, NO. 9, SEPTEMBER 2005 2455 Eddy Currents Induced the calculation of eddy currents in a two-layer conducting rod of finite length excited by a coaxial circular coil. Index Terms--Coil impedance, eddy current, eigenfunction expansion, finite rod. I. INTRODUCTION
Paris-Sud XI, Université de
1 EXPERIMENTAL VALIDATION OF AN EDDY CURRENT PROBE DEDICATED TO THE MULTI-FREQUENCY IMAGING OF BORE ______________________________________________________________________________________ Article info : Submitted on February 2012 Published on October 2012 Key words : Eddy currents, non dedicated to the eddy current imaging of sub-millimetric surface breaking defects appearing in bore holes
Finite element methods for 3D eddy current prob-lems in bounded domains subject to realistic
RodrÃguez, Rodolfo
Finite element methods for 3D eddy current prob- lems in bounded domains subject to realistic techniques to approximate eddy current prob- lems. The focus of the article is on the analysis of weak]), magnetostatics ([59, 60, 80, 81, 109, 110, 114]), eddy current ([1, 2, 3, 6, 7, 8, 9, 19, 20, 21, 23, 24, 25, 26
Subramaniam, Anandh
Vacuum Induction Melting Unit Induction heating is a process wherein induced eddy currents heat field and circulating eddy currents are induced within the metals. Flow of eddy currents leads an AC current through a water cooled copper coil and a metallic charge is placed in a ceramic (or
Eddy-current probe impedance due to a volumetric flaw J. R. Bowler and S. A. Jenkins
Bowler, John R.
Eddy-current probe impedance due to a volumetric flaw J. R. Bowler and S. A. Jenkins University 25 January 1991) Eddy current induced in a metal by a coil carrying an alternating current may, or inclusions. In eddy-current nondestructive evaluation, defectsare commonly sensedby a change of the coil
STUDY FOR THE DESIGN OF AN EDDY CURRENT ARRAY PROBE FOR THE IMAGING OF AERONAUTICAL FASTENER HOLES
Paris-Sud XI, Université de
STUDY FOR THE DESIGN OF AN EDDY CURRENT ARRAY PROBE FOR THE IMAGING OF AERONAUTICAL FASTENER HOLES Wilson, 94230 Cachan France (joubert@satie.ens-cachan.fr) Abstract: The design of an eddy current imaging, eddy currents, imaging probe, finite element modelling, pickup coil array, printed-circuit- board coil
Two-dimensional calculation of eddy currents on external conducting walls induced by low-n external 1997; accepted 8 December 1997 The results of two-dimensional calculations of eddy currents induced on external conducting walls surrounding a tokamak are reported. The computed eddy currents are generated
Nagy, Peter B.
2007-01-01T23:59:59.000Z
NDT&E International 40 (2007) 555565 Lift-off effect in high-frequency eddy current conductivity online 12 June 2007 Abstract Precision eddy current measurements have been shown to be capable, the eddy current inspection frequency has to be as high as 5080 MHz. Unfortunately, spurious self
Eddy current residual stress profiling in surface-treated engine alloys Bassam A. Abu-Nabaha1
Nagy, Peter B.
Eddy current residual stress profiling in surface-treated engine alloys Bassam A. Abu-Nabaha1 version received 3 June 2008 ) Recent research results indicate that eddy current conductivity profile is calculated from the measured frequency-dependent apparent eddy current conductivity spectrum
MUSIC-TYPE ALGORITHM FOR EDDY-CURRENT NONDESTRUC-TIVE EVALUATION OF SMALL DEFECTS IN METAL PLATES
Paris-Sud XI, Université de
MUSIC-TYPE ALGORITHM FOR EDDY-CURRENT NONDESTRUC- TIVE EVALUATION OF SMALL DEFECTS IN METAL PLATES Eddy-Current nondestructive evaluation of metal plates is of interest in a wide range of applications in the lower frequency band (kHz) for eddy-current testing, to retrieve small void defects inside a conducting
Hua, Yingbo
. 451 Eddy Current Tomography for Metal Solidification Imaging Minh H. Pham* , Yingbo Hua* , Neil B of molten metal inside a pipe by eddy currents. A complete mathematical model is developed which reveals functions in multiple layered media. Keywords: eddy current tomography, electromagnetic field, numerical
Ida, Nathan
746 IEEE TRANSACTIONS ON MAGNETICS, VOL. 36, NO. 4, JULY 2000 Solving 3D Eddy Current ProblemsD eddy current prob- lems. The asymmetry of the facet related functions in the edge el- ement basis- ments is compared through an example. Index Terms--Eddy currents, finite element modeling, second order
ccsd-00085042,version1-11Jul2006 A Two-dimensional eddy current model using thin
Paris-Sud XI, Université de
ccsd-00085042,version1-11Jul2006 A Two-dimensional eddy current model using thin inductors Youcef a mathematical model for eddy currents in two dimensional geometries where the conductors are thin domains. We Mathematical modelling of eddy current problems often involves multiple conductors with various sizes
Zakharov, Leonid E.
web page: http://w3.pppl.gov/~ zakharov Equilibrium reconstruction in eddy current environment and small size tokamaks the eddy currents in the passive structures affect both the interpretation the time history of the discharge and sig nals, mitigates uncertainties associated with the eddy currents
Garfinkel, Chaim I.
Barotropic Impacts of Surface Friction on Eddy Kinetic Energy and Momentum Fluxes: An Alternative energy decreases, a response that is inconsistent with the conventional barotropic governor mechanism on eddy momentum fluxes and eddy kinetic energy. Analysis of the pseudomomentum budget shows
Anatomy and evolution of a cyclonic mesoscale eddy observed in the northeastern Pacific tropical and evolution of a cyclonic mesoscale eddy observed in the northeastern Pacific tropical-subtropical transition zone, J. Geophys. Res. Oceans, 118, doi:10.1002/ 2013JC009339. 1. Introduction [2] Mesoscale eddy
Tandon, Amit
Segmentation and Tracking of Mesoscale Eddies in Numeric Ocean Models Vishal Sood, Bin John suggested that the mesoscale eddies and mesoscale features play a strong role in carrying heat poleward oceanographers an invaluable tool to assess mesoscale eddies and the Lagrangian characteristics of this mesoscale
The role of large eddy fluctuations in the Madison Dynamo Experiment
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin Transition in the Earth'sConnect,LLC THEofMaterials
Wadley, Haydn
permission. Eddy current sensing of vertical Bridgman semiconductor crystal growth Dharmasena, Kumar Pradeepa
Hickey, Barbara
Current. Results from three years of field studies5 demonstrate that the eddy increases in spatial extent-driven currents in the surface Ekman12 layer cause the eddy to be "leaky" on its southern perimeter. Eddy surfaceInfluences of the Juan de Fuca Eddy on circulation, nutrients, and phytoplankton1 production
Hua, Yingbo
2000-01-01T23:59:59.000Z
the solidification of molten metal by eddy currents: I Minh H Pham, Yingbo Hua and Neil B Gray The Department@ee.mu.oz.au Received 27 May 1999, in final form 20 December 1999 Abstract. This paper presents an eddy-current for this imaging task other than that of eddy currents. The eddy-current technique is a nondestructive technique
Wadley, Haydn
permission. Eddy current sensing of cadmium zinc telluride crystal growth Choi, Byoung-Woo William Pro
Interannual variability of summer biochemical enhancement in relation to mesoscale eddies the 1300-km-long eastern shelf break accompanied by a mesoscale eddy field (Okkonen, 2001a). Eddies occur., 2002). Mesoscale eddies, which penetrate to depths of at least 1000 m (Roden, 1995; Mizobata et al
Eddy PV Fluxes in the Kuroshio Extension at 144o-148oE Stuart P. Bishop* and D. Randolph Wa6s#
Rhode Island, University of
km Eddy PV Fluxes in the Kuroshio Extension at 144o-148oE Stuart P A. IntroducCon D. Divergent Vs. RotaConal Eddy PV Fluxes E. Eddy Growth G. STMW ModificaCon: SchemaCc Summary C. Time-Mean PV EquaCon & Eddy PV Flux B
Impact of mesoscale eddies on water transport between the Pacific Ocean and the Bering Sea
Prants, S V; Budyansky, M V; Uleysky, M Yu
2013-01-01T23:59:59.000Z
Sea surface height anomalies observed by satellites in 1993--2012 are combined with simulation and observations by surface drifters and Argo floats to study water flow pattern in the Near Strait (NS) connected the Pacific Ocean with the Bering Sea. Daily Lagrangian latitudinal maps, computed with the AVISO surface velocity field, and calculation of the transport across the strait show that the flow through the NS is highly variable and controlled by mesoscale and submesoscale eddies in the area. On the seasonal scale, the flux through the western part of the NR is negatively correlated with the flux through its eastern part ($r=-0.93$). On the interannual time scale, a significant positive correlation ($r=0.72$) is diagnosed between the NS transport and the wind stress in winter. Increased southward component of the wind stress decreases the northward water transport through the strait. Positive wind stress curl over the strait area in winter--spring generates the cyclonic circulation and thereby enhances the...
Ko, Ray T.; Blodgett, Mark P. [Metals, Ceramics, and NDE Division, Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433 (United States); Sathish, Shamachary; Boehnlein, Thomas R. [Structural Integrity Division, University of Dayton Research Institute, 300 College Park, Dayton, Ohio 45469-0120 (United States)
2008-02-28T23:59:59.000Z
The shot peening intensity of nickel base materials has been examined with an innovative eddy current measurement. The goal is to provide a nondestructive tool to quantitatively evaluate the surface conditions after shot peening. Traditionally, the residual stress caused by the shot peening process can be examined by X-ray diffraction. Recent eddy current works have shown promising results in evaluating the small conductivity variation due to the residual stress. This study explores the feasibility of utilizing the cable which connects to a network analyzer and a conventional eddy current probe to monitor the surface conditions due to the shot peening.
Surface Characterization of Stainless Steel Part by Eddy Current
Andersen, Eric S.; Hockey, Ronald L.; Prince, James M.; Good, Morris S.
2003-10-01T23:59:59.000Z
The Pacific Northwest National Laboratory (PNNL) has nearly a 40 year history of research and development in the field of nondestructive evaluation (NDE). One area of NDE expertise at PNNL is electromagnetic testing which includes a field of eddy current testing (ET). One benefit is that ET can typically be performed at high speeds, and as a result has found many applications in process monitoring and poduction lines. ET has been used in the nuclear, aerospace, and automotive industries for many years. Et technology lends itself well to the detection of near-surface or surface breaking defects such as surface scratches. This paper provides an overview of theory regarding the usage of ET, selected application studies performed by PNNL, a safety analysis, and a wrtie up pertaining to the operations of ET to detect surface scratches.
Workshops and problems for benchmarking eddy current codes
Turner, L.R.; Davey, K.; Ida, N.; Rodger, D.; Kameari, A.; Bossavit, A.; Emson, C.R.I.
1988-08-01T23:59:59.000Z
A series of six workshops was held in 1986 and 1987 to compare eddy current codes, using six benchmark problems. The problems included transient and steady-state ac magnetic fields, close and far boundary conditions, magnetic and non-magnetic materials. All the problems were based either on experiments or on geometries that can be solved analytically. The workshops and solutions to the problems are described. Results show that many different methods and formulations give satisfactory solutions, and that in many cases reduced dimensionality or coarse discretization can give acceptable results while reducing the computer time required. A second two-year series of TEAM (Testing Electromagnetic Analysis Methods) workshops, using six more problems, is underway. 12 refs., 15 figs., 4 tabs.
Computer programs for eddy-current defect studies
Pate, J. R.; Dodd, C. V. [Oak Ridge National Lab., TN (USA)
1990-06-01T23:59:59.000Z
Several computer programs to aid in the design of eddy-current tests and probes have been written. The programs, written in Fortran, deal in various ways with the response to defects exhibited by four types of probes: the pancake probe, the reflection probe, the circumferential boreside probe, and the circumferential encircling probe. Programs are included which calculate the impedance or voltage change in a coil due to a defect, which calculate and plot the defect sensitivity factor of a coil, and which invert calculated or experimental readings to obtain the size of a defect. The theory upon which the programs are based is the Burrows point defect theory, and thus the calculations of the programs will be more accurate for small defects. 6 refs., 21 figs.
Popov, Peter
in porous media (soil, porous rocks, etc.) x Elasticity problems in composite materials (adobe, concrete/29 Presentation outline s Brief overview of upscaling methods in deformable porous media s The Fluid upscaling of flow in deformable porous media #12;June 6, 2007 Large-Scale Scientific Computations'07
Paik, Joongcheol [University of Minnesota; Sotiropoulos, Fotis [University of Minnesota; Sale, Michael J [ORNL
2005-06-01T23:59:59.000Z
A numerical method is developed for carrying out unsteady Reynolds-averaged Navier-Stokes (URANS) simulations and detached-eddy simulations (DESs) in complex 3D geometries. The method is applied to simulate incompressible swirling flow in a typical hydroturbine draft tube, which consists of a strongly curved 90 degree elbow and two piers. The governing equations are solved with a second-order-accurate, finite-volume, dual-time-stepping artificial compressibility approach for a Reynolds number of 1.1 million on a mesh with 1.8 million nodes. The geometrical complexities of the draft tube are handled using domain decomposition with overset (chimera) grids. Numerical simulations show that unsteady statistical turbulence models can capture very complex 3D flow phenomena dominated by geometry-induced, large-scale instabilities and unsteady coherent structures such as the onset of vortex breakdown and the formation of the unsteady rope vortex downstream of the turbine runner. Both URANS and DES appear to yield the general shape and magnitude of mean velocity profiles in reasonable agreement with measurements. Significant discrepancies among the DES and URANS predictions of the turbulence statistics are also observed in the straight downstream diffuser.
Asaad, Sameh W; Bellofatto, Ralph E; Brezzo, Bernard; Haymes, Charles L; Kapur, Mohit; Parker, Benjamin D; Roewer, Thomas; Tierno, Jose A
2014-01-28T23:59:59.000Z
A plurality of target field programmable gate arrays are interconnected in accordance with a connection topology and map portions of a target system. A control module is coupled to the plurality of target field programmable gate arrays. A balanced clock distribution network is configured to distribute a reference clock signal, and a balanced reset distribution network is coupled to the control module and configured to distribute a reset signal to the plurality of target field programmable gate arrays. The control module and the balanced reset distribution network are cooperatively configured to initiate and control a simulation of the target system with the plurality of target field programmable gate arrays. A plurality of local clock control state machines reside in the target field programmable gate arrays. The local clock state machines are configured to generate a set of synchronized free-running and stoppable clocks to maintain cycle-accurate and cycle-reproducible execution of the simulation of the target system. A method is also provided.
Eddy covariance flux measurements of pollutant gases in urban Mexico City
Velasco, Erik
Eddy covariance (EC) flux measurements of the atmosphere/surface exchange of gases over an urban area are a direct way to improve and evaluate emissions inventories, and, in turn, to better understand urban atmospheric ...
Evidence for Enhanced Eddy Mixing at Middepth in the Southern Ocean K. SHAFER SMITH
Marshall, John
Evidence for Enhanced Eddy Mixing at Middepth in the Southern Ocean K. SHAFER SMITH Center; Robinson and McWilliams 1974; Stammer 1997; Smith 2007), extracting their energy from the stores
Shuckburgh, Emily
A diagnostic framework is presented, based on the Nakamura effective diffusivity, to investigate the regional variation in eddy diffusivity. Comparison of three different diffusivity calculations enables the effects of ...
A comparison of eddy current effects in a single sided magnetic thrust bearing
DeWeese, Randall Thomas
1996-01-01T23:59:59.000Z
finite element studies of magnetic thrust bearings using static bench testing procedures to investigate configurations that promote eddy current reduction. Several rotor/stator configurations, including solid metal, laminated washers, tapewound lam...
Subduction in an eddy-resolving state estimate of the northeast Atlantic Ocean
Gebbie, Geoffrey Alexander, 1975-
2004-01-01T23:59:59.000Z
Relatively little is known about the role of eddies in controlling subduction in the eastern half of the subtropical gyre. Here, a new tool to study the eastern North Atlantic Ocean is created by combining a regional, ...
Microsoft Word - CX-Big Eddy-Redmond-WoodPolesFY13_WEB.doc
Broader source: Energy.gov (indexed) [DOE]
4, 2013 REPLY TO ATTN OF: KEPR-4 SUBJECT: Environmental Clearance Memorandum Richard Heredia Project Manager - TEP-TPP-1 Proposed Action: Big Eddy-Redmond No. 1 Wood Pole...
Enhancement of Mesoscale Eddy Stirring at Steering Levels in the Southern Ocean
Marshall, John C.
Meridional cross sections of effective diffusivity in the Southern Ocean are presented and discussed. The effective diffusivity, K[subscript eff], characterizes the rate at which mesoscale eddies stir properties on interior ...
EDDY CURRENT INVERSION AND ESTIMATION METRICS FOR EVALUATING THERMAL BARRIER COATINGS
Sabbagh, Harold A.; Murphy, R. Kim; Sabbagh, Elias H. [Victor Technologies LLC, Bloomington, IN 47401 (United States); Knopp, Jeremy S. [Air Force Research Laboratory, Wright-Patterson AFB, OH 45433 (United States); Aldrin, John C. [Computational Tools, Gurnee, IL 60031 (United States); Nyenhuis, John [Dept. of Electric Computer Engineering, Purdue University, West Lafayette, IN (United States)
2010-02-22T23:59:59.000Z
In this paper, sophisticated eddy-current techniques incorporating model-based inverse methods were successfully demonstrated to measure the thickness and remaining-life of high-temperature coatings. To further assure the performance of these inverse methods, several estimation metrics including Fisher Information, Cramer-Rao Lower Bound (CRLB), covariance, and singular value decomposition (SVD) are introduced. The connections and utility of these metrics are illustrated in the design of eddy current methods for estimating layer thickness, conductivity and probe liftoff.
Parametric Studies and Optimization of Eddy Current Techniques through Computer Modeling
Todorov, E. I. [EWI, Engineering and NDE, 1250 Arthur E. Adams Dr., Columbus, OH 43221-3585 (United States)
2007-03-21T23:59:59.000Z
The paper demonstrates the use of computer models for parametric studies and optimization of surface and subsurface eddy current techniques. The study with high-frequency probe investigates the effect of eddy current frequency and probe shape on the detectability of flaws in the steel substrate. The low-frequency sliding probe study addresses the effect of conductivity between the fastener and the hole, frequency and coil separation distance on detectability of flaws in subsurface layers.
Method for removal of random noise in eddy-current testing system
Levy, Arthur J. (Schenectady, NY)
1995-01-01T23:59:59.000Z
Eddy-current response voltages, generated during inspection of metallic structures for anomalies, are often replete with noise. Therefore, analysis of the inspection data and results is difficult or near impossible, resulting in inconsistent or unreliable evaluation of the structure. This invention processes the eddy-current response voltage, removing the effect of random noise, to allow proper identification of anomalies within and associated with the structure.
Eddy current inspection of power plant heat-exchanger tubing in the USA
Fishkin, P.; Nash, J. [MQS Inspection, Inc., Chicago, IL (United States)
1995-02-01T23:59:59.000Z
The latest experience in the eddy current inspection of heat-exchanger tubing by means of ID probes is reported and generalized. The authors demonstrate the feasibility of using modern, general-purpose, digital eddy current flaw detectors equipped with microprocessors, displays, the capability for recording inspection results on paper or magnetic media, sound and visual alarms. The NDE personnel qualification and certification requirements are described.
Stegner Alexandre
extreme cases, coherent cyclones do not emerge at all, and only an anticyclonic vortex street appears.6. Hence, we found that a large-scale wake could differ strongly from the classical Karman street when elongated. In the Earth's ocean, large-scale eddies such as submesoscale coherent vortex,5 meddies
Chardin, Jonathan; Aubert, Dominique; Puchwein, Ewald
2015-01-01T23:59:59.000Z
We calibrate here cosmological radiative transfer simulation with ATON/RAMSES with a range of measurements of the Lyman alpha opacity from QSO absorption spectra. We find the Lyman alpha opacity to be very sensitive to the exact timing of hydrogen reionisation. Models reproducing the measured evolution of the mean photoionisation rate and average mean free path reach overlap at z ~ 7 and predict an accelerated evolution of the Lyman alpha opacity at z > 6 consistent with the rapidly evolving luminosity function of Lyman alpha emitters in this redshift range. Similar to "optically thin" simulations our full radiative transfer simulations fail, however, to reproduce the high-opacity tail of the Lyman alpha opacity PDF at z > 5. We argue that this is due to spatial UV fluctuations in the post-overlap phase of reionisation on substantially larger scales than predicted by our source model, where the ionising emissivity is dominated by large numbers of sub-L* galaxies. We further argue that this suggests a signific...
Bianconi, Andrea
2014-01-01T23:59:59.000Z
Background: The epidemiology of the slightly radioactive contrast agent named Thorotrast presents a very long latency period between the injection and the development of the related pathologies. It is an example of the more general problem posed by a radioactive internal contaminant whose effects are not noteworthy in the short term but become dramatic in the long period. A point that is still to be explored is fluctuations (in space and time) in the localized absorption of radiation by the tissues. Methods: A Monte Carlo simulation code has been developed to study over a 30 year period the daily absorption of alpha radiation by micrometer sized portions of tissue placed at a distance of 0-100 micrometers from a model source, that approximates a compact thorium dioxide source in liver or spleen whose size is larger or equal to 20 micrometers. The biological depletion of the daughter nuclei of the thorium series is taken into account. The initial condition assumes chemically purified natural thorium. Results: ...
Distance dependence of the phase signal in eddy current microscopy
Roll, Tino; Fischer, Ulrich; Schleberger, Marika
2008-01-01T23:59:59.000Z
Atomic force microscopy using a magnetic tip is a promising tool for investigating conductivity on the nano-scale. By the oscillating magnetic tip eddy currents are induced in the conducting parts of the sample which can be detected in the phase signal of the cantilever. However, the origin of the phase signal is still controversial because theoretical calculations using a monopole appoximation for taking the electromagnetic forces acting on the tip into account yield an effect which is too small by more than two orders of magnitude. In order to determine the origin of the signal we used especially prepared gold nano patterns embedded in a non-conducting polycarbonate matrix and measured the distance dependence of the phase signal. Our data clearly shows that the interacting forces are long ranged and therefore, are likely due to the electromagnetic interaction between the magnetic tip and the conducting parts of the surface. Due to the long range character of the interaction a change in conductivity of $\\Del...
Eddy pump dredging: Does it produce water quality impacts?
Creek, K.D. [Pacific Gas and Electric Co., Ramon, CA (United States); Sagraves, T.H. [RESNA Industries, Magalia, CA (United States)
1995-12-31T23:59:59.000Z
During a prototype demonstration at Pacific Gas and Electric Company`s (PG&E`s) Cresta Reservoir, the feasibility of a new dredging technique was tested for its reported ability to produce only minimal water quality impacts. The technique, developed by PBMK Consultants and Engineers, uses the EDDY Pump, a patented submerged slurry pump system with a higher solids-to-liquid ratio and lower re-suspension of sediment than achieved by conventional suction dredging. Turbidity and total suspended solids concentrations of water samples collected adjacent to and downstream of the pump head were similar to those of samples collected adjacent to and upstream of the pump head. Dissolved oxygen downstream of the pump head remained near saturation. The dredged sediment was pumped 600 m upstream of the pump head and discharged back to the surface of Cresta Reservoir. Increases in turbidity and total suspended solids downstream of the discharge site were minor. Throughout the demonstration, turbidity levels and total suspended solids concentrations remained well below allowable levels set by the California Regional Water Quality Control Board - no more than a 25 NTU turbidity increase over ambient background nor more than 80 mg/I total suspended solids, absolute.
Variable current speed controller for eddy current motors
Gerth, H.L.; Bailey, J.M.; Casstevens, J.M.; Dixon, J.H.; Griffith, B.O.; Igou, R.E.
1982-03-12T23:59:59.000Z
A speed control system for eddy current motors is provided in which the current to the motor from a constant frequency power source is varied by comparing the actual motor speed signal with a setpoint speed signal to control the motor speed according to the selected setpoint speed. A three-phase variable voltage autotransformer is provided for controlling the voltage from a three-phase power supply. A corresponding plurality of current control resistors is provided in series with each phase of the autotransformer output connected to inputs of a three-phase motor. Each resistor is connected in parallel with a set of normally closed contacts of plurality of relays which are operated by control logic. A logic circuit compares the selected speed with the actual motor speed obtained from a digital tachometer monitoring the motor spindle speed and operated the relays to add or substract resistance equally in each phase of the motor input to vary the motor current to control the motor at the selected speed.
Three-dimensional hydrodynamic simulations of the combustion of a neutron star into a quark star
Matthias Herzog; Friedrich K. Roepke
2011-09-02T23:59:59.000Z
We present three-dimensional numerical simulations of turbulent combustion converting a neutron star into a quark star. Hadronic matter, described by a micro-physical finite-temperature equation of state, is converted into strange quark matter. We assume this phase, represented by a bag-model equation of state, to be absolutely stable. Following the example of thermonuclear burning in white dwarfs leading to Type Ia supernovae, we treat the conversion process as a potentially turbulent deflagration. Solving the non-relativistic Euler equations using established numerical methods we conduct large eddy simulations including an elaborate subgrid scale model, while the propagation of the conversion front is modeled with a level-set method. Our results show that for large parts of the parameter space the conversion becomes turbulent and therefore significantly faster than in the laminar case. Despite assuming absolutely stable strange quark matter, in our hydrodynamic approximation an outer layer remains in the hadronic phase, because the conversion front stops when it reaches conditions under which the combustion is no longer exothermic.
Non-Destructive Evaluation of Thermal Spray Coating Interface Quality by Eddy Current Method
B.Mi; X. Zhao; R. Bayles
2006-05-26T23:59:59.000Z
Thermal spray coating is usually applied through directing molten or softened particles at very high velocities onto a substrate. An eddy current non-destructive inspection technique is presented here for thermal spray coating interface quality characterization. Several high-velocity-oxy-fuel (HVOF) coated steel plates were produced with different surface preparation conditions before applying the coating, e.g., grit-blasted surface, wire-brush cleaned surface, and a dirty surface. A quad-frequency eddy current probe was used to manually scan over the coating surface to evaluate the bonding quality. Experimental results show that the three surface preparation conditions can be successfully differentiated by looking into the impedance difference observed from the eddy current probe. The measurement is fairly robust and consistent. More specimens are also prepared with variations of process parameters, such as spray angle, stand-off distance, and application of corrosion protective sealant, etc. They are blindly tested to evaluate the reliability of the eddy current system. Quantitative relations between the coating bond strength and the eddy current response are also established with the support of destructive testing. This non-contact, non-destructive, easy to use technique has the potential for evaluating the coating quality immediately after its application so that any defects can be corrected immediately.
Chen, Qingyan "Yan"
300072, China * Phone: (765) 496-7562, FAX: (765) 496-0539, Email: yanchen@purdue.edu Abstract AccurateG = Turbulence generation terms jx = Spatial coordinate k = Turbulence kinetic energy y = Normalized wall term traffic forecast (ACI, 2006). Commercial airplane passengers travel in an enclosed cabin
Adaptive Detached Eddy Simulation of a High Lift Wing with Active Flow
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisiting the TWP TWP Related LinksATHENA AccountManagement |ARQ AAdYoung GuestControl
Scalable, efficient epidemiological simulation
Eubank, S. G. (Stephen G.)
2001-01-01T23:59:59.000Z
We describe the design and implementation of a system for simulating the spread of disease among individuals in a large urban population over the course of several weeks, In contrast to traditional approaches, we do not assume uniform mixing among large sub-populations or split the population into spatial or demographic subpopulations determined a priori. Instead, we rely on empirical estimates of the social network, or contact patterns, that are produced by TRANSIMS, a large-scale simulation of transportation systems.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Schmitt, J. C. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA; Bialek, J. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA; Lazerson, S. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA; Majeski, R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
2014-11-01T23:59:59.000Z
The Lithium Tokamak eXperiment is a spherical tokamak with a close-fitting low-recycling wall composed of thin lithium layers evaporated onto a stainless steel-lined copper shell. Long-lived non-axisymmetric eddy currents are induced in the shell and vacuum vessel by transient plasma and coil currents and these eddy currents influence both the plasma and the magnetic diagnositc signals that are used as constraints for equilibrium reconstruction. A newly installed set of re-entrant magnetic diagnostics and internal saddle flux loops, compatible with high-temperatures and lithium environments, is discussed. Details of the axisymmetric (2D) and non-axisymmetric (3D) treatments of the eddy currents and the equilibrium reconstruction are presented.
Non-Destructive Evaluation of Thermal Spray Coating Interface Quality By Eddy Current Method
B. Mi; G. Zhao; R. Bayles
2006-08-10T23:59:59.000Z
Thermal spray coating is usually applied through directing molten or softened particles at very high velocities onto a substrate. An eddy current non-destructive inspection technique is presented here for thermal spray coating interface quality characterization. Several high-velocity-oxy-fuel (HVOF) coated steel plates were produced with various surface preparation conditions or spray process parameters. A quad-frequency eddy current probe was used to manually scan over the coating surface to evaluate the bonding quality. Experimental results show that different surface preparation conditions and varied process parameters can be successfully differentiated by the impedance value observed from the eddy current probe. The measurement is fairly robust and consistent. This non-contact, nondestructive, easy-to-use technique has the potential for evaluating the coating quality immediately after its application so that any defects can be corrected immediately.
Schmitt, J. C., E-mail: jschmitt@pppl.gov; Lazerson, S.; Majeski, R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Bialek, J. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)
2014-11-15T23:59:59.000Z
The Lithium Tokamak eXperiment is a spherical tokamak with a close-fitting low-recycling wall composed of thin lithium layers evaporated onto a stainless steel-lined copper shell. Long-lived non-axisymmetric eddy currents are induced in the shell and vacuum vessel by transient plasma and coil currents and these eddy currents influence both the plasma and the magnetic diagnostic signals that are used as constraints for equilibrium reconstruction. A newly installed set of re-entrant magnetic diagnostics and internal saddle flux loops, compatible with high-temperatures and lithium environments, is discussed. Details of the axisymmetric (2D) and non-axisymmetric (3D) treatments of the eddy currents and the equilibrium reconstruction are presented.
On The Use of Eddy Current Brakes as Tunable, Fast Turn-On Viscous Dampers For Haptic Rendering
Hayward, Vincent
On The Use of Eddy Current Brakes as Tunable, Fast Turn-On Viscous Dampers For Haptic Rendering, linear dampers for haptic rendering using a prototype haptic device outfitted with eddy current brakes discuss the results from haptic experiments for rendering viscosity, virtual walls and virtual friction
Deep-Sea Research II 54 (2007) 789796 The Leeuwin Current and its eddies: An introductory overview
Feng, Ming
2007-01-01T23:59:59.000Z
Deep-Sea Research II 54 (2007) 789796 The Leeuwin Current and its eddies: An introductory overview 2007 Elsevier Ltd. All rights reserved. Keywords: Mesoscale eddy; Leeuwin Current; Leeuwin Undercurrent December 2006; accepted 24 December 2006 Available online 21 June 2007 Abstract The Leeuwin Current (LC
Zeller, K.; Massman, W.; Stocker, D.; Fox, D.G.; Stedman, D.
1988-01-01T23:59:59.000Z
The Pawnee Grassland Eddy Correlation Dry Deposition Project is described. Instrumentation, methods of analysis, and initial data and research findings are presented. Data from this eddy correlation system show agreement with: previously observations of deposition velocities for atmospheric ozone, NO/sub 2/ and NOx; micrometeorological theory; micrometeorological site characteristics.
Deep-Sea Research I 53 (2006) 17181728 A North Atlantic deep-water eddy in the
Miami, University of
2006-01-01T23:59:59.000Z
properties in the SE Atlantic Ocean and SW Indian Ocean, we conclude that the eddy was formed in the Agulhas, which flows from the SE Atlantic around the Agulhas Bank. A deeply penetrating Agulhas Ring spun up. Keywords: Circulation; Indian Ocean; Boundary currents; Agulhas Current; Deep water; Oceanic eddies 1
averaged; suspended sediment is modeled through use of the advection-dispersion equation which yieldsMEASUREMENTS OF VELOCITY PROFILES AND SUSPENDED-SEDIMENT CONCENTRATIONS IN A COLORADO RIVER EDDY profiles and suspended-sediment concentration were made in a recirculating eddy along the Colorado River
Enabling Advanced Modeling and Simulations for Fuel-Flexible Combustors
Pitsch, Heinz
2010-05-31T23:59:59.000Z
The overall goal of the present project is to enable advanced modeling and simulations for the design and optimization of fuel-flexible turbine combustors. For this purpose we use a high fidelity, extensively-tested large-eddy simulation (LES) code and state-of-the-art models for premixed/partially-premixed turbulent combustion developed in the PI's group. In the frame of the present project, these techniques are applied, assessed, and improved for hydrogen enriched premixed and partially premixed gas-turbine combustion. Our innovative approaches include a completely consistent description of flame propagation; a coupled progress variable/level set method to resolve the detailed flame structure, and incorporation of thermal-diffusion (non-unity Lewis number) effects. In addition, we have developed a general flamelet-type transformation holding in the limits of both non-premixed and premixed burning. As a result, a model for partially premixed combustion has been derived. The coupled progress variable/level method and the general flamelet transformation were validated by LES of a lean-premixed low-swirl burner that has been studied experimentally at Lawrence Berkeley National Laboratory. The model is extended to include the non-unity Lewis number effects, which play a critical role in fuel-flexible combustor with high hydrogen content fuel. More specifically, a two-scalar model for lean hydrogen and hydrogen-enriched combustion is developed and validated against experimental and direct numerical simulation (DNS) data. Results are presented to emphasize the importance of non-unity Lewis number effects in the lean-premixed low-swirl burner of interest in this project. The proposed model gives improved results, which shows that the inclusion of the non-unity Lewis number effects is essential for accurate prediction of the lean-premixed low-swirl flame.
Paris-Sud XI, Université de
for Eddy Current Computation in Thin Conductive Shells T. Le-Duc, G. Meunier, O. Chadebec, and J Fourier, CNRS UMR 5269, Grenoble, France In order to compute eddy current distributions in thin conductive conductive shells. I. INTRODUCTION I NTEGRAL formulations dedicated to the computation of eddy currents
RodrÃguez, Rodolfo
AN EDDY CURRENT PROBLEM IN TERMS OF A TIME-PRIMITIVE OF THE ELECTRIC FIELD WITH NON-LOCAL SOURCE Abstract. The aim of this paper is to analyze a formulation of the eddy current problem in terms of a time and phrases: Eddy current problems, time-dependent electromagnetic problems, input current intensities
Eindhoven, Technische Universiteit
Eddy currents in a transverse MRI gradient coil. J.M.B. Kroot, S.J.L. van Eijndhoven, A.A.F. van de logarithmically singular kernel represents inductive effects related to the occurrence of eddy currents on the development of eddy currents in the gradient coils, which have a negative effect on the uniformity
Hua, Yingbo
2000-01-01T23:59:59.000Z
the solidification of molten metal by eddy currents: II Minh H Pham, Yingbo Hua and Neil B Gray The Department by the induced eddy currents inside the innermost cylinder. Identification of the CSG of an infinitely long space. The existing eddy-current inverse techniques [5,6] solve very different problems. In this paper
Nagy, Peter B.
ABSTRACT The measurement of eddy current conductivity, in view of its frequen- cy dependent of the near surface electrical conductivity measured by the eddy current method in the presence of surface dissipated, leaving only the surface roughness. Eddy current electri- cal conductivity measurements were