V European Conference on Computational Fluid Dynamics ECCOMAS CFD 2010
Berning, Torsten
V European Conference on Computational Fluid Dynamics ECCOMAS CFD 2010 J. C. F. Pereira and A, increase the mixing of fuel and oxidant, control formation of harmful emissions, and increase the life
Computational Fluid Dynamics (CFD) Modelling on Soot Yield for Fire
Computational Fluid Dynamics (CFD) Modelling on Soot Yield for Fire Engineering Assessment Yong S (CFD) Modelling is now widely used by fire safety engineers throughout the world as a tool of the smoke control design as part of the performance based fire safety design in the current industry
Dr. Chenn Zhou
2008-10-15T23:59:59.000Z
Pulverized coal injection (PCI) into the blast furnace (BF) has been recognized as an effective way to decrease the coke and total energy consumption along with minimization of environmental impacts. However, increasing the amount of coal injected into the BF is currently limited by the lack of knowledge of some issues related to the process. It is therefore important to understand the complex physical and chemical phenomena in the PCI process. Due to the difficulty in attaining trus BF measurements, Computational fluid dynamics (CFD) modeling has been identified as a useful technology to provide such knowledge. CFD simulation is powerful for providing detailed information on flow properties and performing parametric studies for process design and optimization. In this project, comprehensive 3-D CFD models have been developed to simulate the PCI process under actual furnace conditions. These models provide raceway size and flow property distributions. The results have provided guidance for optimizing the PCI process.
V European Conference on Computational Fluid Dynamics ECCOMAS CFD 2010
Nicoud, Franck
for the optimisation of the energy consumption (heating or cooling); it is then necessary to develop accurate LES. Sequeira (Eds) Lisbon, Portugal,14-17 June 2010 IS THE DYNAMIC PROCEDURE APPROPRIATE FOR ALL SGS MODELS ? H, Subgrid- scale model Abstract. The rapid growth of supercomputers will probably make the use of Large eddy
JACKSON VL
2011-08-31T23:59:59.000Z
The primary purpose of the tank mixing and sampling demonstration program is to mitigate the technical risks associated with the ability of the Hanford tank farm delivery and celtification systems to measure and deliver a uniformly mixed high-level waste (HLW) feed to the Waste Treatment and Immobilization Plant (WTP) Uniform feed to the WTP is a requirement of 24590-WTP-ICD-MG-01-019, ICD-19 - Interface Control Document for Waste Feed, although the exact definition of uniform is evolving in this context. Computational Fluid Dynamics (CFD) modeling has been used to assist in evaluating scaleup issues, study operational parameters, and predict mixing performance at full-scale.
Thanh D.B. Nguyen; Young-Il Lim; Seong-Joon Kim; Won-Hyeon Eom; Kyung-Seun Yoo [Hankyong National University, Jungangno (Republic of Korea). Laboratory of Functional Analysis of Complex Systems (FACS)
2008-11-15T23:59:59.000Z
A turbulent reacting flow computational fluid dynamics (CFD) model involving a droplet size distribution function in the discrete droplet phase is first built for selective noncatalytic reduction (SNCR) processes using urea solution as a NOx removal reagent. The model is validated with the experimental data obtained from a pilot-scale urea-based SNCR reactor installed with a 150 kW gas burner. New kinetic parameters of seven chemical reactions for the urea-based NOx reduction are identified and incorporated into the three-dimensional turbulent flow CFD model. The two-phase droplet model with the non-uniform droplet size is also combined with the CFD model to predict the trajectory of the droplets and to examine the mixing between the flue gas and reagents. The maximum NO reduction efficiency of about 80%, experimentally measured at the reactor outlet, is obtained at 940{degree}C and a normalized stoichiometric ratio (NSR) = 2.0 under the conditions of 11% excess air and low CO concentration (10-15 ppm). At the reaction temperature of 940{degree}C, the difference of a maximum of 10% between experiments and simulations of the NO reduction percentage is observed for NSR = 1.0, 1.5, and 2.0. The ammonia slip is overestimated in CFD simulation at low temperatures, especially lower than 900{degree}C. However, the CFD simulation results above 900{degree}C show a reasonable agreement with the experimental data of NOx reduction and ammonia slip as a function of the NSR. 31 refs., 3 figs., 6 tabs.
Leishear, Robert A.; Lee, Si Y.; Poirier, Michael R.; Steeper, Timothy J.; Ervin, Robert C.; Giddings, Billy J.; Stefanko, David B.; Harp, Keith D.; Fowley, Mark D.; Van Pelt, William B.
2012-10-07T23:59:59.000Z
Computational fluid dynamics (CFD) is recognized as a powerful engineering tool. That is, CFD has advanced over the years to the point where it can now give us deep insight into the analysis of very complex processes. There is a danger, though, that an engineer can place too much confidence in a simulation. If a user is not careful, it is easy to believe that if you plug in the numbers, the answer comes out, and you are done. This assumption can lead to significant errors. As we discovered in the course of a study on behalf of the Department of Energy's Savannah River Site in South Carolina, CFD models fail to capture some of the large variations inherent in complex processes. These variations, or scatter, in experimental data emerge from physical tests and are inadequately captured or expressed by calculated mean values for a process. This anomaly between experiment and theory can lead to serious errors in engineering analysis and design unless a correction factor, or safety factor, is experimentally validated. For this study, blending times for the mixing of salt solutions in large storage tanks were the process of concern under investigation. This study focused on the blending processes needed to mix salt solutions to ensure homogeneity within waste tanks, where homogeneity is required to control radioactivity levels during subsequent processing. Two of the requirements for this task were to determine the minimum number of submerged, centrifugal pumps required to blend the salt mixtures in a full-scale tank in half a day or less, and to recommend reasonable blending times to achieve nearly homogeneous salt mixtures. A full-scale, low-flow pump with a total discharge flow rate of 500 to 800 gpm was recommended with two opposing 2.27-inch diameter nozzles. To make this recommendation, both experimental and CFD modeling were performed. Lab researchers found that, although CFD provided good estimates of an average blending time, experimental blending times varied significantly from the average.
Zevenhoven, Ron
Introduction to Computational Fluid Dynamics 424512 E #1 - rz Introduction to Computational Fluid Dynamics (iCFD) 424512.0 E, 5 sp 1. Introduction; Fluid dynamics (lecture 1 of 4) Ron Zevenhoven Åbo to Computational Fluid Dynamics 424512 E #1 - rz maj 2015 Åbo Akademi Univ - Thermal and Flow Engineering
Computational fluid dynamic applications
Chang, S.-L.; Lottes, S. A.; Zhou, C. Q.
2000-04-03T23:59:59.000Z
The rapid advancement of computational capability including speed and memory size has prompted the wide use of computational fluid dynamics (CFD) codes to simulate complex flow systems. CFD simulations are used to study the operating problems encountered in system, to evaluate the impacts of operation/design parameters on the performance of a system, and to investigate novel design concepts. CFD codes are generally developed based on the conservation laws of mass, momentum, and energy that govern the characteristics of a flow. The governing equations are simplified and discretized for a selected computational grid system. Numerical methods are selected to simplify and calculate approximate flow properties. For turbulent, reacting, and multiphase flow systems the complex processes relating to these aspects of the flow, i.e., turbulent diffusion, combustion kinetics, interfacial drag and heat and mass transfer, etc., are described in mathematical models, based on a combination of fundamental physics and empirical data, that are incorporated into the code. CFD simulation has been applied to a large variety of practical and industrial scale flow systems.
Computational Fluid Dynamics Study of Aerosol Transport and Deposition Mechanisms
Tang, Yingjie
2012-07-16T23:59:59.000Z
In this work, various aerosol particle transport and deposition mechanisms were studied through the computational fluid dynamics (CFD) modeling, including inertial impaction, gravitational effect, lift force, interception, and turbophoresis, within...
Boutchko, R.
2014-01-01T23:59:59.000Z
emission tomography systems and computational fluid dynamicsa computational ?uid dynamics (CFD) model of the systemthe computational domain. A Cartesian coordinate system was
Hajdukiewicz, M.; Keane, M.; O'Flynn, B.; O'Grady, W.
2010-01-01T23:59:59.000Z
Computational Fluid Dynamics (CFD) is a robust tool for modeling interactions within and between fluids and solids. CFD can help understand and predict phenomena that are difficult to test experimentally leading to cleaner, ...
Analysis of fluid flow and heat transfer in a rib grit roughened surface solar air heater using CFD
Karmare, S.V. [Department of Mechanical Engineering, Government College Engineering, Karad 415 124, Maharashtra (India); Shivaji University, Kolhapur, Maharashtra (India); Tikekar, A.N. [Department of Mechanical Engineering, Walchand College of Engineering, Sangli (India); Shivaji University, Kolhapur, Maharashtra (India)
2010-03-15T23:59:59.000Z
This paper presents the study of fluid flow and heat transfer in a solar air heater by using Computational Fluid Dynamics (CFD) which reduces time and cost. Lower side of collector plate is made rough with metal ribs of circular, square and triangular cross-section, having 60 inclinations to the air flow. The grit rib elements are fixed on the surface in staggered manner to form defined grid. The system and operating parameters studied are: e/D{sub h} = 0.044, p/e = 17.5 and l/s = 1.72, for the Reynolds number range 3600-17,000. To validate CFD results, experimental investigations were carried out in the laboratory. It is found that experimental and CFD analysis results give the good agreement. The optimization of rib geometry and its angle of attack is also done. The square cross-section ribs with 58 angle of attack give maximum heat transfer. The percentage enhancement in the heat transfer for square plate over smooth surface is 30%. (author)
National Ignition Facility computational fluid dynamics modeling and light fixture case studies
Martin, R.; Bernardin, J.; Parietti, L.; Dennison, B.
1998-02-01T23:59:59.000Z
This report serves as a guide to the use of computational fluid dynamics (CFD) as a design tool for the National Ignition Facility (NIF) program Title I and Title II design phases at Lawrence Livermore National Laboratory. In particular, this report provides general guidelines on the technical approach to performing and interpreting any and all CFD calculations. In addition, a complete CFD analysis is presented to illustrate these guidelines on a NIF-related thermal problem.
Zhai, Zhiqiang, 1971-
2003-01-01T23:59:59.000Z
Building energy simulation (ES) and computational fluid dynamics (CFD) can play important roles in building design by providing essential information to help design energy-efficient, thermally comfortable and healthy ...
Using the FLUENT computational fluid dynamics code to model the NACOK corrosion test
Parks, Benjamin T
2004-01-01T23:59:59.000Z
As a part of advancing nuclear technology, computational fluid dynamics (CFD) analysis offers safer and lower-cost results relative to experimental work. Its use as a safety analysis tool is gaining much broader acceptance ...
CSE Master Specialization Fluid Dynamics
Lang, Annika
CSE Master Specialization Fluid Dynamics Course Semester Fluid Dynamics II HS Quantitative Flow Energie- und Verfahrenstechnik FS Biofluiddynamics FS #12;CSE in Fluid Dynamics: Very large high in Fluid Dynamics: Physiology of the inner ear MicroCT imaging Multilayer MFS for Stokes flow simulations
Computational fluid dynamics modeling of coal gasification in a pressurized spout-fluid bed
Zhongyi Deng; Rui Xiao; Baosheng Jin; He Huang; Laihong Shen; Qilei Song; Qianjun Li [Southeast University, Nanjing (China). Key Laboratory of Clean Coal Power Generation and Combustion Technology of Ministry of Education
2008-05-15T23:59:59.000Z
Computational fluid dynamics (CFD) modeling, which has recently proven to be an effective means of analysis and optimization of energy-conversion processes, has been extended to coal gasification in this paper. A 3D mathematical model has been developed to simulate the coal gasification process in a pressurized spout-fluid bed. This CFD model is composed of gas-solid hydrodynamics, coal pyrolysis, char gasification, and gas phase reaction submodels. The rates of heterogeneous reactions are determined by combining Arrhenius rate and diffusion rate. The homogeneous reactions of gas phase can be treated as secondary reactions. A comparison of the calculated and experimental data shows that most gasification performance parameters can be predicted accurately. This good agreement indicates that CFD modeling can be used for complex fluidized beds coal gasification processes. 37 refs., 7 figs., 5 tabs.
Ship hull resistance calculations using CFD methods
Voxakis, Petros
2012-01-01T23:59:59.000Z
In past years, the computational power and run-time required by Computational Fluid Dynamics (CFD) codes restricted their use in ship design space exploration. Increases in computational power available to designers, in ...
6. Fluid mechanics: fluid statics; fluid dynamics
Zevenhoven, Ron
Figure Pressure (a scalar!) is defined as surface force / area, for example pb = Fb / (d·w) = p @ z = z1 Picture: KJ05 Fluid volume h·d·w with density and mass m = h·d·w· z = z1 In engineering forces Fn+ Fs = 0 or - py·h·w + py·h·w = 0 py = 0 Similarly Fw+ Fe= 0 gives px = 0, There are three
Fluid Dynamics Seminar Fluid Dynamics Research Centre
Davies, Christopher
France) 8th Nov. Future Trends in Condition Monitoring of Rotating Machines Using System Identification Simulation of the Cooling of a Simplified Brake Disc Dr. Thorsten J. Möller, (Institute for Fluid Mechanics
Fluid Dynamics Seminar Fluid Dynamics Research Centre
Thomas, Peter J.
France) 8 th Nov. Future Trends in Condition Monitoring of Rotating Machines Using System Identification Simulation of the Cooling of a Simplified Brake Disc Dr. Thorsten J. Möller, (Institute for Fluid Mechanics
Solution characters of iterative coupling between energy simulation and CFD programs
Chen, Qingyan "Yan"
1 Solution characters of iterative coupling between energy simulation and CFD programs Zhiqiang Energy simulation (ES) and computational fluid dynamics (CFD) provide important and complementary information for building energy and indoor environment designs. A coupled ES and CFD simulation can eliminate
CFD Simulation of Dynamic Thrust and Radial Forces on a Vertical Axis Wind Turbine Blade
Tullis, Stephen
CFD Simulation of Dynamic Thrust and Radial Forces on a Vertical Axis Wind Turbine Blade K. Mc vibration source of a small scale vertical axis wind turbine. The dynamic loading on the blades detail. 1. INTRODUCTION A prototype of a small scale vertical axis wind turbine is currently being field
Comparative Study: CFD ?P Versus Measured ?P for 30% Flexible Ducts
Ugursal, A.; Culp, C.
2006-01-01T23:59:59.000Z
Systems Lab Texas A&M University College Station, TX ABSTRACT This study modeled air flow and pressure drops in non-metallic flexible ducts using Computational Fluid Dynamic (CFD) analysis. CFD simulation results showed very close comparison... on both ends. A CFD model was built and simulations were run under different volumetric air flows. The static pressure drop for those conditions were analyzed and displayed. The final CFD model is tuned until the closest results to the experimental...
Barran, Brian Arthur
2006-08-16T23:59:59.000Z
This thesis presents a method for simulating fluids on a view dependent grid structure to exploit level-of-detail with distance to the viewer. Current computer graphics techniques, such as the Stable Fluid and Particle Level Set methods...
Computational fluid dynamic modeling of fluidized-bed polymerization reactors
Rokkam, Ram [Ames Laboratory
2012-11-02T23:59:59.000Z
Polyethylene is one of the most widely used plastics, and over 60 million tons are produced worldwide every year. Polyethylene is obtained by the catalytic polymerization of ethylene in gas and liquid phase reactors. The gas phase processes are more advantageous, and use fluidized-bed reactors for production of polyethylene. Since they operate so close to the melting point of the polymer, agglomeration is an operational concern in all slurry and gas polymerization processes. Electrostatics and hot spot formation are the main factors that contribute to agglomeration in gas-phase processes. Electrostatic charges in gas phase polymerization fluidized bed reactors are known to influence the bed hydrodynamics, particle elutriation, bubble size, bubble shape etc. Accumulation of electrostatic charges in the fluidized-bed can lead to operational issues. In this work a first-principles electrostatic model is developed and coupled with a multi-fluid computational fluid dynamic (CFD) model to understand the effect of electrostatics on the dynamics of a fluidized-bed. The multi-fluid CFD model for gas-particle flow is based on the kinetic theory of granular flows closures. The electrostatic model is developed based on a fixed, size-dependent charge for each type of particle (catalyst, polymer, polymer fines) phase. The combined CFD model is first verified using simple test cases, validated with experiments and applied to a pilot-scale polymerization fluidized-bed reactor. The CFD model reproduced qualitative trends in particle segregation and entrainment due to electrostatic charges observed in experiments. For the scale up of fluidized bed reactor, filtered models are developed and implemented on pilot scale reactor.
ENERGY SERIES "CFD Modeling and its Application in Steam Condenser
Bergman, Keren
SEMINAR: ENERGY SERIES "CFD Modeling and its Application in Steam Condenser Performance Improvement will discuss the application of CFD to steam condensers, an area where both of the above mentioned limitations of computational fluid dynamics, having applied these techniques extensively in the design large heat exchangers
CFD Analysis of a Novel High Speed Rotary On/Off Valve 283 Proc. of 6th
Li, Perry Y.
CFD Analysis of a Novel High Speed Rotary On/Off Valve 283 Proc. of 6th FPNI-PhD Symp. West Lafayette 2010, pp. 283-294 CFD ANALYSIS OFA NOVEL HIGH SPEED ROTARY ON/OFF VALVE Meng WANG1 , Haink TU a novel type of high speed rotary on/off valve is analyzed using CFD (Computational Fluid Dynamics
Coupling remote sensing with computational fluid dynamics modelling to estimate lake chlorophyll form 17 October 2000; accepted 1 June 2001 Abstract A remotely sensed image of Loch Leven, a shallow in the remotely sensed image. It is proposed that CFD modelling benefits the interpretation of remotely sensed
Computational fluid dynamic simulations of chemical looping fuel reactors utilizing gaseous fuels
Mahalatkar, K.; Kuhlman, J.; Huckaby, E.D.; O'Brien, T.
2011-01-01T23:59:59.000Z
A computational fluid dynamic(CFD) model for the fuel reactor of chemical looping combustion technology has been developed,withspecialfocusonaccuratelyrepresentingtheheterogeneous chemicalreactions.Acontinuumtwo-fluidmodelwasusedtodescribeboththegasandsolidphases. Detailedsub-modelstoaccountforfluid–particleandparticle–particleinteractionforceswerealso incorporated.Twoexperimentalcaseswereanalyzedinthisstudy(Son andKim,2006; Mattisonetal., 2001). SimulationswerecarriedouttotestthecapabilityoftheCFDmodeltocapturechangesinoutletgas concentrationswithchangesinnumberofparameterssuchassuperficialvelocity,metaloxide concentration,reactortemperature,etc.Fortheexperimentsof Mattissonetal.(2001), detailedtime varyingoutletconcentrationvalueswerecompared,anditwasfoundthatCFDsimulationsprovideda reasonablematchwiththisdata.
Ultrarelativistic fluid dynamics
David W. Neilsen; Matthew W. Choptuik
1999-04-20T23:59:59.000Z
This is the first of two papers examining the critical collapse of spherically symmetric perfect fluids with the equation of state P = (Gamma -1)rho. Here we present the equations of motion and describe a computer code capable of simulating the extremely relativistic flows encountered in critical solutions for Gamma <= 2. The fluid equations are solved using a high-resolution shock-capturing scheme based on a linearized Riemann solver.
Chen, Qingyan "Yan"
and Computational Fluid Dynamics (CFD) have been widely used in simulations of building airflow distribution takes several minutes to perform an hour-by-hour dynamic simulation of a whole building for one year. "Validation of a coupled multizone and CFD program for building airflow and contaminant transport simulations
On the application of computational fluid dynamics codes for liquefied natural gas dispersion.
Luketa-Hanlin, Anay Josephine; Koopman, Ronald P. (Lawrence Livermore National Laboratory, Livermore, CA); Ermak, Donald (Lawrence Livermore National Laboratory, Livermore, CA)
2006-02-01T23:59:59.000Z
Computational fluid dynamics (CFD) codes are increasingly being used in the liquefied natural gas (LNG) industry to predict natural gas dispersion distances. This paper addresses several issues regarding the use of CFD for LNG dispersion such as specification of the domain, grid, boundary and initial conditions. A description of the k-{var_epsilon} model is presented, along with modifications required for atmospheric flows. Validation issues pertaining to the experimental data from the Burro, Coyote, and Falcon series of LNG dispersion experiments are also discussed. A description of the atmosphere is provided as well as discussion on the inclusion of the Coriolis force to model very large LNG spills.
V European Conference on Computational Fluid Dynamics ECCOMAS CFD 2010
Abgrall, RÃ©mi
QUANTIFICATION OF SHOCKED FLOWS, COMPARISON WITH A NON-INTRUSIVE POLYNOMIAL CHAOS METHOD R. Abgrall , P) in the context of compressible inviscid flows. More specifically, we aim at comparing a well documented non-intrusive in some details the method recently proposed in [1]; Section 3 reviews the non-intrusive Polynomial Chaos
V European Conference on Computational Fluid Dynamics ECCOMAS CFD 2010
Paris-Sud XI, Université de
QUANTIFICATION OF SHOCKED FLOWS, COMPARISON WITH A NON-INTRUSIVE POLYNOMIAL CHAOS METHOD R. Abgrall , P) in the context of compressible inviscid flows. More specifically, we aim at comparing a well documented non-intrusive proposed in [?]; Section 3 reviews the non-intrusive Polynomial Chaos approach also employed in this study
Comparative Study: CFD ?P Versus Measured ?P for 30% Flexible Ducts
Ugursal, A.; Culp, C.
2006-01-01T23:59:59.000Z
COMPARATIVE STUDY: CFD ?P VERSUS MEASURED ?P FOR 30% FLEXIBLE DUCTS Ahmet U?ursal Ph.D. Student, Department of Architecture Texas A&M University College Station, TX Charles Culp, Ph.D., P.E. Associate Professor, Department of Architecture... & Associate Director, Energy Systems Lab Texas A&M University College Station, TX ABSTRACT This study modeled air flow and pressure drops in non-metallic flexible ducts using Computational Fluid Dynamic (CFD) analysis. CFD simulation results showed...
CFD Analysis of Nuclear Fuel Bundles and Spacer Grids for PWR Reactors
Capone, Luigi
2012-10-19T23:59:59.000Z
The analysis of the turbulent flows in nuclear fuel bundles is a very interesting task to optimize the efficiency of modern nuclear power plants. The proposed study utilizes Computational Fluid Dynamics (CFD) to characterize the flow pattern...
Villasmil Urdaneta, Larry Alfonso
2002-01-01T23:59:59.000Z
seals performance and leakage information indicating that friction factor increases as the seal clearance is increased, contradicting the theory predictions based on Moody's pipe-friction model. A Computational Fluid Dynamics (CFD) code is used...
Frisani, Angelo
2011-08-08T23:59:59.000Z
. The design and validation of the RCCS is necessary to demonstrate that VHTRs can survive to the postulated accidents. The commercial Computational Fluid Dynamics (CFD) STAR-CCM+/ V3.06.006 code was used for three-dimensional system modeling and analysis...
Lawson, M. J.; Li, Y.; Sale, D. C.
2011-10-01T23:59:59.000Z
This paper describes the development of a computational fluid dynamics (CFD) methodology to simulate the hydrodynamics of horizontal-axis tidal current turbines. Qualitative measures of the CFD solutions were independent of the grid resolution. Conversely, quantitative comparisons of the results indicated that the use of coarse computational grids results in an under prediction of the hydrodynamic forces on the turbine blade in comparison to the forces predicted using more resolved grids. For the turbine operating conditions considered in this study, the effect of the computational timestep on the CFD solution was found to be minimal, and the results from steady and transient simulations were in good agreement. Additionally, the CFD results were compared to corresponding blade element momentum method calculations and reasonable agreement was shown. Nevertheless, we expect that for other turbine operating conditions, where the flow over the blade is separated, transient simulations will be required.
Continuum limit of lattice gas fluid dynamics
Teixeira, C.M.
1992-01-01T23:59:59.000Z
The general theory for multiple-speed lattice gas algorithm (LGAs) is developed where previously only a single-speed theory existed. A series of microdynamical multiple-speed models are developed that effectively erase the underlying lattice from the macroscopic dynamics allowing the LGA to reproduce the results of continuum hydrodynamics exactly. The underlying lattice is the 4D FCHC lattice. This lattice: (1) Permits all integral energies, (2) Has sufficient symmetry to allow for an isotropic stress tensor for each energy individually, (3) Allows interaction amongst all energies, and (4) Has discrete microscopic Galilean invariance, all of which allows the extension of the model to higher-speeds. This lattice is the only regular lattice with these remarkable properties, all of which are required to show that the discreteness artifacts completely disappear from the LGA in the limit of infinite speeds, so that correct continuum hydrodynamic behavior results. The author verifies the removal of the discreteness artifacts from the momentum equation using a decaying shear wave experiment and shows they are still invisible for Mach numbers up to M [approximately].4 beyond the theoretical limit. Flow between flat plates replicated the expected parabolic profile of Poiseuille flow in the mean when started from rest. Two separate measurements of the kinematic viscosity of the fluid (normal pressure drop and the microscopic particle force at the wall) agreed with each other and with the shear wave viscosity to better than 1%. Cylinder flow simulations accurately reproduced drag coefficients and eddy-length to diameter ratios for Re[le]45 to within the error of experimental observation. At higher Reynolds number, Re [approx equal] 65, vortex shedding was observed to occur. CFD results for flow past cylinders at similar Reynolds numbers produce either erroneous results or rely on artificially perturbing the flow to cause phenomena that does not occur naturally in the method.
CFD evaluation of pipeline gas stratification at low fluid flow due to temperature effects
Brar, Pardeep Singh
2005-02-17T23:59:59.000Z
*A*?T On simplifying the above equation, applying forward difference and integrating both sides from west (W) to east (E), we get the following form of equation: ()() 2*( )* WW P WEE E P P EW kA T TkA T T rh T T x xx ? ?? ? ?? ? =?? 18 This is the general equation... and how much it differs from the CFD Analysis results. 41 0 2040608010 Z/D -1 0 1 2 P e rcen t D i fferen c e Single Elbow Upstream Simulated USM Compared To CFD Results, ?T Constant 5.5 o K (10 o F), 0.15 m/s (0.5 ft/s) 13.8 o K (25 o F), 0.15 m/s (0...
Computational Fluid Dynamic Analysis of the VHTR Lower Plenum Standard Problem
Richard W. Johnson; Richard R. Schultz
2009-07-01T23:59:59.000Z
The United States Department of Energy is promoting the resurgence of nuclear power in the U. S. for both electrical power generation and production of process heat required for industrial processes such as the manufacture of hydrogen for use as a fuel in automobiles. The DOE project is called the next generation nuclear plant (NGNP) and is based on a Generation IV reactor concept called the very high temperature reactor (VHTR), which will use helium as the coolant at temperatures ranging from 450 ºC to perhaps 1000 ºC. While computational fluid dynamics (CFD) has not been used for past safety analysis for nuclear reactors in the U. S., it is being considered for safety analysis for existing and future reactors. It is fully recognized that CFD simulation codes will have to be validated for flow physics reasonably close to actual fluid dynamic conditions expected in normal and accident operational situations. To this end, experimental data have been obtained in a scaled model of a narrow slice of the lower plenum of a prismatic VHTR. The present report presents results of CFD examinations of these data to explore potential issues with the geometry, the initial conditions, the flow dynamics and the data needed to fully specify the inlet and boundary conditions; results for several turbulence models are examined. Issues are addressed and recommendations about the data are made.
ITP Chemicals: Technology Roadmap for Computational Fluid Dynamics...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Fluid Dynamics, January 1999 ITP Chemicals: Technology Roadmap for Computational Fluid Dynamics, January 1999 cfdroadmap.pdf More Documents & Publications A Workshop to Identify...
Dynamical instability of collapsing radiating fluid
Sharif, M., E-mail: msharif.math@pu.edu.pk; Azam, M., E-mail: azammath@gmail.com [University of the Punjab, Department of Mathematics (Pakistan)
2013-06-15T23:59:59.000Z
We take the collapsing radiative fluid to investigate the dynamical instability with cylindrical symmetry. We match the interior and exterior cylindrical geometries. Dynamical instability is explored at radiative and non-radiative perturbations. We conclude that the dynamical instability of the collapsing cylinder depends on the critical value {gamma} < 1 for both radiative and nonradiative perturbations.
Simulation of Complex Fluids using Dissipative Particle Dynamics
Title: Simulation of Complex Fluids using Dissipative Particle Dynamics Abstract: Dissipative Particle Dynamics (DPD) is a relatively new mesoscopic method ...
Swing Check Valve Design Criteria and CFD Validation
Dallstream, Brian E.; Fricke, Brian A.; Becker, Bryan R. [University of Missouri-Kansas City (United States)
2006-07-01T23:59:59.000Z
This paper provides information on swing check valve selection criteria suitable for nuclear power plant applications. In this project, four swing check valves were analyzed to demonstrate the implementation and application of this information. In this example, swing check valves were selected according to 'ASME Boiler and Pressure Vessel Code, Section III' and 'ASME B16.34, Valves Flanged, Threaded, and Welding End'. This paper also discusses the utilization of Computational Fluid Dynamics Software (CFD) as a means to analyze valve design. The use of CFD is a relatively new approach for validation of valve design that is becoming invaluable due to the high cost of physical bench testing. The Instrument Society of America (ISA) Analysis Division and the American Society of Mechanical Engineers (ASME) Computational Fluid Dynamics Technical Committee have taken a proactive approach in setting standards and practices for the use of CFD in design and validation. (authors)
Williams, P.T.
1993-09-01T23:59:59.000Z
As the field of computational fluid dynamics (CFD) continues to mature, algorithms are required to exploit the most recent advances in approximation theory, numerical mathematics, computing architectures, and hardware. Meeting this requirement is particularly challenging in incompressible fluid mechanics, where primitive-variable CFD formulations that are robust, while also accurate and efficient in three dimensions, remain an elusive goal. This dissertation asserts that one key to accomplishing this goal is recognition of the dual role assumed by the pressure, i.e., a mechanism for instantaneously enforcing conservation of mass and a force in the mechanical balance law for conservation of momentum. Proving this assertion has motivated the development of a new, primitive-variable, incompressible, CFD algorithm called the Continuity Constraint Method (CCM). The theoretical basis for the CCM consists of a finite-element spatial semi-discretization of a Galerkin weak statement, equal-order interpolation for all state-variables, a 0-implicit time-integration scheme, and a quasi-Newton iterative procedure extended by a Taylor Weak Statement (TWS) formulation for dispersion error control. Original contributions to algorithmic theory include: (a) formulation of the unsteady evolution of the divergence error, (b) investigation of the role of non-smoothness in the discretized continuity-constraint function, (c) development of a uniformly H{sup 1} Galerkin weak statement for the Reynolds-averaged Navier-Stokes pressure Poisson equation, (d) derivation of physically and numerically well-posed boundary conditions, and (e) investigation of sparse data structures and iterative methods for solving the matrix algebra statements generated by the algorithm.
Zevenhoven, Ron
-study Introduction to Computational Fluid Dynamics 424512 E #3 - rz maj 2015 Åbo Akademi Univ -Thermal and Flow and Flow Engineering - Piispankatu 8, 20500 Turku 4/104 Laminar vs. turbulent pipe flow HKTJ07 #12;Introduction to Computational Fluid Dynamics 424512 E #3 - rz maj 2015 Åbo Akademi Univ -Thermal and Flow
Lee, S.
2011-05-05T23:59:59.000Z
The Savannah River Remediation (SRR) Organization requested that Savannah River National Laboratory (SRNL) develop a Computational Fluid Dynamics (CFD) method to mix and blend the miscible contents of the blend tanks to ensure the contents are properly blended before they are transferred from the blend tank; such as, Tank 50H, to the Salt Waste Processing Facility (SWPF) feed tank. The work described here consists of two modeling areas. They are the mixing modeling analysis during miscible liquid blending operation, and the flow pattern analysis during transfer operation of the blended liquid. The transient CFD governing equations consisting of three momentum equations, one mass balance, two turbulence transport equations for kinetic energy and dissipation rate, and one species transport were solved by an iterative technique until the species concentrations of tank fluid were in equilibrium. The steady-state flow solutions for the entire tank fluid were used for flow pattern analysis, for velocity scaling analysis, and the initial conditions for transient blending calculations. A series of the modeling calculations were performed to estimate the blending times for various jet flow conditions, and to investigate the impact of the cooling coils on the blending time of the tank contents. The modeling results were benchmarked against the pilot scale test results. All of the flow and mixing models were performed with the nozzles installed at the mid-elevation, and parallel to the tank wall. From the CFD modeling calculations, the main results are summarized as follows: (1) The benchmark analyses for the CFD flow velocity and blending models demonstrate their consistency with Engineering Development Laboratory (EDL) and literature test results in terms of local velocity measurements and experimental observations. Thus, an application of the established criterion to SRS full scale tank will provide a better, physically-based estimate of the required mixing time, and elevation of transfer pump for minimum sludge disturbance. (2) An empirical equation for a tank with no cooling coils agrees reasonably with the current modeling results for the dual jet. (3) From the sensitivity study of the cooling coils, it was found that the tank mixing time for the coiled tank was about two times longer than that of the tank fluid with no coils under the 1/10th scale, while the coiled tank required only 50% longer than the one without coils under the full scale Tank 50H. In addition, the time difference is reduced when the pumping U{sub o}d{sub o} value is increased for a given tank. (4) The blending time for T-shape dual jet pump is about 20% longer than that of 15{sup o} upward V-shape pump under the 1/10th pilot-scale tank, while the time difference between the two pumps is about 12% for the full-scale Tank 50H. These results are consistent with the literature information. (5) A transfer pump with a solid-plate suction screen operating at 130 gpm can be located 9.5 inches above settled sludge for 2 in screen height in a 85 ft waste tank without disturbing any sludge. Detailed results are summarized in Table 13. Final pump performance calculations were made by using the established CW pump design, and operating conditions to satisfy the two requirements of minimum sludge disturbance, and adequate blending of tank contents. The final calculation results show that the blending times for the coiled and uncoiled tanks coupled with the CW pump design are 159 and 83 minutes, respectively. All the results are provided in Table 16.
Computational Fluid Dynamics Analysis of Flexible Duct Junction Box Design
Beach, R.; Prahl, D.; Lange, R.
2013-12-01T23:59:59.000Z
IBACOS explored the relationships between pressure and physical configurations of flexible duct junction boxes by using computational fluid dynamics (CFD) simulations to predict individual box parameters and total system pressure, thereby ensuring improved HVAC performance. Current Air Conditioning Contractors of America (ACCA) guidance (Group 11, Appendix 3, ACCA Manual D, Rutkowski 2009) allows for unconstrained variation in the number of takeoffs, box sizes, and takeoff locations. The only variables currently used in selecting an equivalent length (EL) are velocity of air in the duct and friction rate, given the first takeoff is located at least twice its diameter away from the inlet. This condition does not account for other factors impacting pressure loss across these types of fittings. For each simulation, the IBACOS team converted pressure loss within a box to an EL to compare variation in ACCA Manual D guidance to the simulated variation. IBACOS chose cases to represent flows reasonably correlating to flows typically encountered in the field and analyzed differences in total pressure due to increases in number and location of takeoffs, box dimensions, and velocity of air, and whether an entrance fitting is included. The team also calculated additional balancing losses for all cases due to discrepancies between intended outlet flows and natural flow splits created by the fitting. In certain asymmetrical cases, the balancing losses were significantly higher than symmetrical cases where the natural splits were close to the targets. Thus, IBACOS has shown additional design constraints that can ensure better system performance.
Computational Fluid Dynamics Analyses on Very High Temperature Reactor Air Ingress
Chang H Oh; Eung S. Kim; Richard Schultz; David Petti; Hyung S. Kang
2009-07-01T23:59:59.000Z
A preliminary computational fluid dynamics (CFD) analysis was performed to understand density-gradient-induced stratified flow in a Very High Temperature Reactor (VHTR) air-ingress accident. Various parameters were taken into consideration, including turbulence model, core temperature, initial air mole-fraction, and flow resistance in the core. The gas turbine modular helium reactor (GT-MHR) 600 MWt was selected as the reference reactor and it was simplified to be 2-D geometry in modeling. The core and the lower plenum were assumed to be porous bodies. Following the preliminary CFD results, the analysis of the air-ingress accident has been performed by two different codes: GAMMA code (system analysis code, Oh et al. 2006) and FLUENT CFD code (Fluent 2007). Eventually, the analysis results showed that the actual onset time of natural convection (~160 sec) would be significantly earlier than the previous predictions (~150 hours) calculated based on the molecular diffusion air-ingress mechanism. This leads to the conclusion that the consequences of this accident will be much more serious than previously expected.
Fluid Dynamics IB Dr Natalia Berloff
are said to form the boundary of a vortex tube. We say that `stretching amplfies vorticity'. It is also as if they were material lines. Or, vortex tubes rotate and stretch just like the material line elementsFluid Dynamics IB Dr Natalia Berloff §2.6 Vorticity Definition: Vorticity = × u. A vortex line
Fluid transport properties by equilibrium molecular dynamics. II. Multicomponent systems
Dysthe, Dag Kristian
Fluid transport properties by equilibrium molecular dynamics. II. Multicomponent systems D. K than 25 years molecular dynamics has been used to study fluid transport properties. Such MD studies and multicenter molecular models.816 d The study of transport properties of certain fluids and classes of fluids
AIR INGRESS ANALYSIS: PART 2 – COMPUTATIONAL FLUID DYNAMIC MODELS
Chang H. Oh; Eung S. Kim; Richard Schultz; Hans Gougar; David Petti; Hyung S. Kang
2011-01-01T23:59:59.000Z
The Idaho National Laboratory (INL), under the auspices of the U.S. Department of Energy, is performing research and development that focuses on key phenomena important during potential scenarios that may occur in very high temperature reactors (VHTRs). Phenomena Identification and Ranking Studies to date have ranked an air ingress event, following on the heels of a VHTR depressurization, as important with regard to core safety. Consequently, the development of advanced air ingress-related models and verification and validation data are a very high priority. Following a loss of coolant and system depressurization incident, air will enter the core of the High Temperature Gas Cooled Reactor through the break, possibly causing oxidation of the in-the core and reflector graphite structure. Simple core and plant models indicate that, under certain circumstances, the oxidation may proceed at an elevated rate with additional heat generated from the oxidation reaction itself. Under postulated conditions of fluid flow and temperature, excessive degradation of the lower plenum graphite can lead to a loss of structural support. Excessive oxidation of core graphite can also lead to the release of fission products into the confinement, which could be detrimental to a reactor safety. Computational fluid dynamic model developed in this study will improve our understanding of this phenomenon. This paper presents two-dimensional and three-dimensional CFD results for the quantitative assessment of the air ingress phenomena. A portion of results of the density-driven stratified flow in the inlet pipe will be compared with results of the experimental results.
Code Verification of the HIGRAD Computational Fluid Dynamics Solver
Van Buren, Kendra L. [Los Alamos National Laboratory; Canfield, Jesse M. [Los Alamos National Laboratory; Hemez, Francois M. [Los Alamos National Laboratory; Sauer, Jeremy A. [Los Alamos National Laboratory
2012-05-04T23:59:59.000Z
The purpose of this report is to outline code and solution verification activities applied to HIGRAD, a Computational Fluid Dynamics (CFD) solver of the compressible Navier-Stokes equations developed at the Los Alamos National Laboratory, and used to simulate various phenomena such as the propagation of wildfires and atmospheric hydrodynamics. Code verification efforts, as described in this report, are an important first step to establish the credibility of numerical simulations. They provide evidence that the mathematical formulation is properly implemented without significant mistakes that would adversely impact the application of interest. Highly accurate analytical solutions are derived for four code verification test problems that exercise different aspects of the code. These test problems are referred to as: (i) the quiet start, (ii) the passive advection, (iii) the passive diffusion, and (iv) the piston-like problem. These problems are simulated using HIGRAD with different levels of mesh discretization and the numerical solutions are compared to their analytical counterparts. In addition, the rates of convergence are estimated to verify the numerical performance of the solver. The first three test problems produce numerical approximations as expected. The fourth test problem (piston-like) indicates the extent to which the code is able to simulate a 'mild' discontinuity, which is a condition that would typically be better handled by a Lagrangian formulation. The current investigation concludes that the numerical implementation of the solver performs as expected. The quality of solutions is sufficient to provide credible simulations of fluid flows around wind turbines. The main caveat associated to these findings is the low coverage provided by these four problems, and somewhat limited verification activities. A more comprehensive evaluation of HIGRAD may be beneficial for future studies.
Zevenhoven, Ron
Akademi University Thermal and Flow Engineering Laboratory tel. 3223 ; ron.zevenhoven@abo.fi Introduction to Computational Fluid Dynamics 424512 E #1 - rz april 2013 Åbo Akademi Univ - Thermal and Flow Engineering Dynamics 424512 E #1 - rz april 2013 Åbo Akademi Univ - Thermal and Flow Engineering - Piispankatu 8, 20500
Thermo-fluid Dynamics of Flash Atomizing Sprays and Single Droplet Impacts
Vu, Henry
2010-01-01T23:59:59.000Z
OF CALIFORNIA RIVERSIDE Thermo-fluid Dynamics of FlashABSTRACT OF THE DISSERTATION Thermo-fluid Dynamics of Flash
Hiroyuki Sato; Richard Johnson; Richard Schultz
2009-09-01T23:59:59.000Z
Three dimensional computational fluid dynamic (CFD) calculations of a typical prismatic very high temperature gas-cooled reactor (VHTR) were conducted to investigate the influence of gap geometry on flow and temperature distributions in the reactor core using commercial CFD code FLUENT. Parametric calculations changing the gap width in a whole core length model of fuel and reflector columns were performed. The simulations show the effects of core by-pass flows in the heated core region by comparing results for several gap widths including zero gap width. The calculation results underline the importance of considering inter-column gap width for the evaluation of maximum fuel temperatures and temperature gradients in fuel blocks. In addition, it is shown that temperatures of core outlet flow from gaps and channels are strongly affected by the gap width of by-pass flow in the reactor core.
Fluid transport properties by equilibrium molecular dynamics. I. Methodology at extreme fluid states
Dysthe, Dag Kristian
Fluid transport properties by equilibrium molecular dynamics. I. Methodology at extreme fluid. We are interested in obtaining a complete picture of the transport mechanisms in molecular fluids 17 November 1998 The Green-Kubo formalism for evaluating transport coefficients by molecular dynamics
Under consideration for publication in J. Fluid Mech. 1 The fluid dynamics of an underfloor air
Linden, Paul F.
Under consideration for publication in J. Fluid Mech. 1 The fluid dynamics of an underfloor air-0411, U.S.A., (Received 30 May 2005) This paper discusses the fluid dynamics of an under floor air developed a system to humidify and ventilate the air supplied to the British House of Commons, air
Performance of coupled building energy and CFD simulations Zhiqiang John Zhaia,*, Qingyan Yan Chenb
Zhai, John Z.
a coupled energy simulation and computational fluid dynamics program with different coupling methods/cooling energy required and building envelope thermal information, such as surface temperature and heat fluxPerformance of coupled building energy and CFD simulations Zhiqiang John Zhaia,*, Qingyan Yan Chenb
Al Hanbali, Ahmad
March 30, 2009 16:44 Geophysical and Astrophysical Fluid Dynamics gafdbo09 Geophysical (geophysical) fluid models: two-dimensional vortical systems in a generalized streamfunction-vorticity rep
Sandia Energy - Computational Fluid Dynamics & Large-Scale Uncertainty...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
& Large-Scale Uncertainty Quantification for Wind Energy Home Highlights - HPC Computational Fluid Dynamics & Large-Scale Uncertainty Quantification for Wind Energy Previous Next...
Petascale Adap,ve Computa,onal Fluid Dynamics
Kemner, Ken
Petascale Adap,ve Computa,onal Fluid Dynamics PI: Kenneth Jansen, University and weight · Reduce biggest expense, i.e. fuel consump,on Wind turbine industry
AFDM: An Advanced Fluid-Dynamics Model
Bohl, W.R.; Parker, F.R. (Los Alamos National Lab., NM (USA)); Wilhelm, D. (Kernforschungszentrum Karlsruhe GmbH (Germany, F.R.). Inst. fuer Neutronenphysik und Reaktortechnik); Berthier, J. (CEA Centre d'Etudes Nucleaires de Grenoble, 38 (France)); Goutagny, L. (CEA Centre d'Etudes Nucleaires de Cadarache, 13 - Saint-Paul-lez-Durance (France). Inst. de Protection et de Surete Nucleaire); Ninokata,
1990-09-01T23:59:59.000Z
AFDM, or the Advanced Fluid-Dynamics Model, is a computer code that investigates new approaches simulating the multiphase-flow fluid-dynamics aspects of severe accidents in fast reactors. The AFDM formalism starts with differential equations similar to those in the SIMMER-II code. These equations are modified to treat three velocity fields and supplemented with a variety of new models. The AFDM code has 12 topologies describing what material contacts are possible depending on the presence or absence of a given material in a computational cell, on the dominant liquid, and on the continuous phase. Single-phase, bubbly, churn-turbulent, cellular, and dispersed flow regimes are permitted for the pool situations modeled. Virtual mass terms are included for vapor in liquid-continuous flow. Interfacial areas between the continuous and discontinuous phases are convected to allow some tracking of phenomenological histories. Interfacial areas are also modified by models of nucleation, dynamic forces, turbulence, flashing, coalescence, and mass transfer. Heat transfer is generally treated using engineering correlations. Liquid-vapor phase transitions are handled with the nonequilibrium, heat-transfer-limited model, whereas melting and freezing processes are based on equilibrium considerations. Convection is treated using a fractional-step method of time integration, including a semi-implicit pressure iteration. A higher-order differencing option is provided to control numerical diffusion. The Los Alamos SESAME equation-of-state has been implemented using densities and temperatures as the independent variables. AFDM programming has vectorized all computational loops consistent with the objective of producing an exportable code. 24 refs., 4 figs.
Fluid Dynamic Models of Flagellar and Ciliary Beating
Fauci, Lisa
University, New Orleans, Louisiana, USA ABSTRACT: We have developed a fluidmechanical model of a eucaryotic mechanics of microtubules, and forces due to nexin links with a surrounding incompressible fluid. This model mechanisms, the passive elastic structure of the axoneme, and the external fluid dynamics. These flagellar
Variational Methods for Computational Fluid Dynamics Annee 2013 -2014.
Alouges, François
are only valid for laminar flow at low Reynolds number. 4. Compute the flow rate F (the quantity of fluid that a fluid is flowing (from left to right) obeying Navier-Syokes equation. 1. Show that there is a stationary1 Variational Methods for Computational Fluid Dynamics Ann´ee 2013 - 2014. X2011. PC 1 Exercise 1
AFDM: An Advanced Fluid-Dynamics Model
Berthier, J. (CEA Centre d'Etudes Nucleaires de Grenoble, 38 (France)); Wilhelm, D. (Kernforschungszentrum Karlsruhe GmbH (Germany, F.R.). Inst. fuer Neutronenphysik und Reaktortechnik); Bohl, W.R. (Los Alamos National Lab., NM (USA))
1990-09-01T23:59:59.000Z
This report consists of three parts. First, for the standard Advanced Fluid-Dynamics Model (AFDM), heat-transfer coefficients between components are worked out, depending on the different possible topologies. Conduction, convection, and radiative heat-transfer mechanisms are modeled. For solid particles, discontinuous phases that obey a rigid'' model, and components lacking relative motion, heat transfer is by conduction. Convection is represented for fluids in motion inside circulating'' bubbles and/or droplets. Radiation is considered between droplets in vapor continuous flow. In addition, a film-boiling model has been formulated, where radiation provides the lower limit on the fuel-to-coolant heat-transfer coefficient. Second, the momentum-exchange coefficients are defined for the standard AFDM. Between a continuous and discontinuous phase, the model consists of both laminar and turbulent terms. The most important feature is the drag coefficient in the turbulent term. It is calculated by a drag similarity hypothesis with limits for large Reynolds numbers, distorted particles,'' and churn-turbulent flow. A unique hysteresis algorithm exists to treat the liquid continuous to vapor continuous transition. Two discontinuous components are coupled using a turbulent term with an input drag coefficient. Fluid- structure momentum exchange is represented with a standard friction-factor correlation. Third, the formulas used for the AFDM simplified Step 1 models are discussed. These include the heat-transfer coefficients, the momentum-exchange functions, and the manner in which interfacial areas are determined from input length scales. The simplified modeling uses steady-state engineering correlations, as in SIMMER-II.
Ris-P.-715(EN) Optics and Fluid Dynamics
Risø-P.-715(EN) Optics and Fluid Dynamics Department Annual Progress Report for 1993 Edited by S Research in the Optics and Fluid Dynamics Department is performed within the following two programme areas: optics and continuum physics. In optics the activities are within (a) optical materials, (b) quasi
Ris-R-1314(EN) Optics and Fluid Dynamics
Risø-R-1314(EN) Optics and Fluid Dynamics Department Annual Progress Report for 2001 Edited by H March 2002 #12;Abstract The Optics and Fluid Dynamics Department performs basic and applied research within three scientific programmes: (1) laser systems and optical materials, (2) optical diagnostics
Optics and Fluid Dynamics ^>*myft Annual Progress Report
Optics and Fluid Dynamics ^>*myft Department Annual Progress Report 1 January - 31 December 1991;Abstract Research in the Optics and Fluid Dynamics Department covers quasi-elas.ic light scattering, optic association. A ? .mmary of activities in 1991 ii presented. Optical diagnostic methods based on quasi
Ris-R-1453(EN) Optics and Fluid Dynamics
Risø-R-1453(EN) Optics and Fluid Dynamics Department Annual Progress Report for 2003 Edited by H May 2004 #12;Abstract The Optics and Fluid Dynamics Department performs basic and applied research within three scientific programmes: (1) laser systems and optical materials, (2) optical diagnostics
Ris-R-1399(EN) Optics and Fluid Dynamics
Risø-R-1399(EN) Optics and Fluid Dynamics Department Annual Progress Report for 2002 Edited by H May 2003 #12;Abstract The Optics and Fluid Dynamics Department performs basic and applied research within three scientific programmes: (1) laser systems and optical materials, (2) optical diagnostics
Optics and Fluid Dynamics Department Intellectual Capital Accounts 1998
Optics and Fluid Dynamics Department Intellectual Capital Accounts 1998 Resources, production and results RISØ-R-1108(EN) Risø National Laboratory Optics and Fluid Dynamics Department Building 128 P for optical information storage, · novel schemes for spatial cryptography, and · new models for surface
The Effects of Geometry on Flexible Duct CFD Simulations
Ugursal, A.; Culp, C.
2008-01-01T23:59:59.000Z
dynamics (CFD) simulations allow variable configurations and are emerging as an alternative to laboratory measurements. Issues with the CFD simulations of flexible ducts have been modeling the complex geometry and the computational requirements to complete...
Russell, Lynn
Geophysical Fluid Dynamics Laboratory general circulation model investigation of the indirect Corporation for Atmospheric Research, Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey, USA V. Ramaswamy, Paul A. Ginoux, and Larry W. Horowitz Geophysical Fluid Dynamics Laboratory, Princeton, New
Fluid dynamic issues in continuous wave short wavelength chemical lasers
Mikatarian, R.R.; Jumper, E.J.; Woolhiser, C.
1988-01-01T23:59:59.000Z
This paper addresses fluid dynamic issues of concern in the design and development of Continuous Wave (CW) Short Wavelength Chemical Lasers (SWCLs). Short Wavelength Chemical Laser technology is in its research stage and SWCL concepts are in their evolving mode. Researchers are presently addressing candidate chemical systems and activation concepts. Since these lasers will be flowing systems, it is necessary to discuss both the probable fluid dynamics issues, because of the inherent complexities fluid dynamicist can support this activity. In addition to addressing the SWCL fluid dynamic issues, this paper will review past fluid dynamic activities in high energy lasers and discuss additional research still required. This paper will also address the various levels of fluid dynamic modeling and how these models can be applied in studying the fluid dynamics of Short Wavelength Chemical Lasers. Where it is felt that specific fluid methodologies are not available, but are required in order to conduct specific analyses, they will be defined. 34 refs., 6 figs., 1 tab.
The Dalles Dam, Columbia River: Spillway Improvement CFD Study
Cook, Chris B.; Richmond, Marshall C.; Serkowski, John A.
2006-06-01T23:59:59.000Z
This report documents development of computational fluid dynamics (CFD) models that were applied to The Dalles spillway for the US Army Corps of Engineers, Portland District. The models have been successfully validated against physical models and prototype data, and are suitable to support biological research and operations management. The CFD models have been proven to provide reliable information in the turbulent high-velocity flow field downstream of the spillway face that is typically difficult to monitor in the prototype. In addition, CFD data provides hydraulic information throughout the solution domain that can be easily extracted from archived simulations for later use if necessary. This project is part of an ongoing program at the Portland District to improve spillway survival conditions for juvenile salmon at The Dalles. Biological data collected at The Dalles spillway have shown that for the original spillway configuration juvenile salmon passage survival is lower than desired. Therefore, the Portland District is seeking to identify operational and/or structural changes that might be implemented to improve fish passage survival. Pacific Northwest National Laboratory (PNNL) went through a sequence of steps to develop a CFD model of The Dalles spillway and tailrace. The first step was to identify a preferred CFD modeling package. In the case of The Dalles spillway, Flow-3D was as selected because of its ability to simulate the turbulent free-surface flows that occur downstream of each spilling bay. The second step in development of The Dalles CFD model was to assemble bathymetric datasets and structural drawings sufficient to describe the dam (powerhouse, non-overflow dam, spillway, fish ladder entrances, etc.) and tailrace. These datasets are documented in this report as are various 3-D graphical representations of The Dalles spillway and tailrace. The performance of the CFD model was then validated for several cases as the third step. The validated model was then applied to address specific SIS design questions. Specifically, the CFD models were used to evaluate flow deflectors, baffle block removal and the effects of spillwalls. The CFD models were also used to evaluate downstream differences at other locations, such as at the Highway 197 bridge piers and Oregon shore islands, due to alterations in spill pattern. CFD model results were analyzed to quantitatively compare impacts of the spillwall that has subsequently been constructed between bays 6 and 7. CFD model results provided detailed information about how the spillwall would impact downstream flow patterns that complemented results from the 1:80 scale physical model. The CFD model was also used to examine relative differences between the juvenile spill pattern used in previous years and the anticipated spill pattern that will be applied once the wall is complete. In addition, the CFD model examined velocity magnitudes over the downstream basalt shelf to investigate potential for erosion under high flow conditions (e.g., 21 kcfs/bay for bays 1 through 6) with the spillwall in place. Several appendices follow the results and discussion sections of this report. These appendices document the large number of CFD simulations that have been performed by PNNL; both spillway improvement study (SIS) related and those performed for related biological tests.
Huang, Samuel H.
. Huang, J. Shi Intelligent CAM Systems Laboratory Department of Mechanical, Industrial and Nuclear and Erlandur Steinthorsson Gas Turbine Fuel Systems Division Parker Hannifin Corporation 9200 Tyler Boulevard Finite Element Analysis (FEA) and Computational Fluid Dynamics (CFD) are used extensively in almost every
Automatic Generation of Quadrilateral Multi-Block Topology for FEA/CFD Applications Samuel H. Huang1
Huang, Samuel H.
Department of Mechanical, Industrial and Nuclear Engineering, University of Cincinnati, Cincinnati, OH 45221 2 Hauenstein & Burmeister, Inc., 2629 30th Avenue South, Minneapolis, MN 55406 3 Gas Turbine Fuel) and Computational Fluid Dynamics (CFD) are used extensively in almost every industry imaginable, including aerospace
Title of dissertation: MODELING, SIMULATING, AND CONTROLLING THE FLUID DYNAMICS
Shapiro, Benjamin
ABSTRACT Title of dissertation: MODELING, SIMULATING, AND CONTROLLING THE FLUID DYNAMICS OF ELECTRO an algorithm to steer indi- vidual particles inside the EWOD system by control of actuators already present number of actuators available in the EWOD system. #12;MODELING, SIMULATING, AND CONTROLLING THE FLUID
Approximate Dynamic Programming for Networks: Fluid Models and Constraint Reduction
Veatch, Michael H.
of approximating functions for the differential cost. The first contribution of this paper is identifying new or piece-wise quadratic. Fluid cost has been used to initialize the value iteration algorithm [5Approximate Dynamic Programming for Networks: Fluid Models and Constraint Reduction Michael H
RESEARCH ARTICLE Fluid dynamics of self-propelled microorganisms,
Goldstein, Raymond E.
RESEARCH ARTICLE Fluid dynamics of self-propelled microorganisms, from individuals to concentrated non-pathogenic soil bacteria are rod-shaped (Fig. 1). Their length ranges from 2 to 8 lm, depending
RESEARCH ARTICLE Fluid dynamics of self-propelled microorganisms,
Cortez, Ricardo
RESEARCH ARTICLE Fluid dynamics of self-propelled microorganisms, from individuals to concentrated00348-007-0387-y #12;Individual cells of these generally non-pathogenic soil bacteria are rod
Computational fluid dynamics (CFD) simulations of aerosol in a u-shaped steam generator tube
Longmire, Pamela
2009-05-15T23:59:59.000Z
velocity is equal to the mean velocity which is known (for instance from turbulence model predictions) plus a fluctuation, which is unknown. The fluctuating velocity component transports particles away from the mean flow and is responsible for particle...
Computational fluid dynamics (CFD) simulations of aerosol in a u-shaped steam generator tube
Longmire, Pamela
2009-05-15T23:59:59.000Z
To quantify primary side aerosol retention, an Eulerian/Lagrangian approach was used to investigate aerosol transport in a compressible, turbulent, adiabatic, internal, wall-bounded flow. The ARTIST experimental project (Phase I) served...
Master Thesis Topics -Wind Energy Meteorology Computational Fluid Dynamics (CFD) -Meteo
Peinke, Joachim
Atmospheric stability and wind farm efficiency First investigations of SCADA data from offshore wind farms. In this master thesis long term power data from offshore wind farms shall be combined with measured atmospheric offshore wind farms. Contact: M.Sc. Martin D¨orenk¨amper - martin.doerenkaemper@forwind.de Dr. Gerald
A Fluid Dynamics Approach to Multi-Robot Chemical Plume Tracing Dimitri Zarzhitsky
computational fluid dy- namics (CFD) grid for calculating derivatives of flow-field variables, such as wind the conservation of mass, New- ton's Second Law, and conservation of energy [1]. For real- istic flows of interest. Our algorithm takes advantage of the lattice formations formed by our robotic agents to simulate
Variational Methods for Computational Fluid Dynamics
Alouges, François
.2.1 Generalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2.2.2 Going back-structure interactions 35 4.1 A non deformable solid in a fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 6 Stokes equations 49 6.1 Mixed finite
Dynamics of fluid-conveying Timoshenko pipes
Petrus, Ryan Curtis
2006-08-16T23:59:59.000Z
that satisfy the ?non-fluid? essential and natural boundary conditions, and determine the non-dimensional critical velocities at which the system goes unstable. Once the critical velocities are ascertained, the second half will begin with a time... and polynomial functions. The trigonometric\\hyperbolic functions are exact solutions to (4.16) subject to cantilevered boundary conditions (4.17)-(4.20). The th non dimensional natural frequency of the non-fluid beam is given by 2 sinh sin cosh cos 0...
Davis, Michael A.
2011-10-21T23:59:59.000Z
to the model that is used in EnergyPlus. 6. Demonstrate that Computational Fluid Dynamics can be used as a design tool that can be used to improve the performance of FPTU. All of the research objectives were achieved and this thesis describes the results... of the CFD model. Chapter IX summarizes the results from the project and provides conclusions from the results. 12 CHAPTER II LITERATURE REVIEW EnergyPlus is currently the standard for building energy simulations (DOE 2009) and includes a model...
CFD analysis of laminar oscillating flows
Booten, C. W. Charles W.); Konecni, S. (Snezana); Smith, B. L. (Barton L.); Martin, R. A. (Richard A.)
2001-01-01T23:59:59.000Z
This paper describes a numerical simulations of oscillating flow in a constricted duct and compares the results with experimental and theoretical data. The numerical simulations were performed using the computational fluid dynamics (CFD) code CFX4.2. The numerical model simulates an experimental oscillating flow facility that was designed to test the properties and characteristics of oscillating flow in tapered ducts, also known as jet pumps. Jet pumps are useful devices in thermoacoustic machinery because they produce a secondary pressure that can counteract an unwanted effect called streaming, and significantly enhance engine efficiency. The simulations revealed that CFX could accurately model velocity, shear stress and pressure variations in laminar oscillating flow. The numerical results were compared to experimental data and theoretical predictions with varying success. The least accurate numerical results were obtained when laminar flow approached transition to turbulent flow.
Recycling Krylov subspaces for CFD applications
Amritkar, Amit; ?wirydowicz, Katarzyna; Tafti, Danesh; Ahuja, Kapil
2015-01-01T23:59:59.000Z
The most popular iterative linear solvers in Computational Fluid Dynamics (CFD) calculations are restarted GMRES and BiCGStab. At the beginning of most incompressible flow calculations, the computation time and the number of iterations to converge for the pressure Poisson equation are quite high. In this case, the BiCGStab algorithm, with relatively cheap but non-optimal iterations, may fail to converge for stiff problems. Thus, a more robust algorithm like GMRES, which guarantees monotonic convergence, is preferred. To reduce the large storage requirements of GMRES, a restarted version - GMRES(m) or its variants - is used in CFD applications. However, GMRES(m) can suffer from stagnation or very slow convergence. For this reason, we use the rGCROT method. rGCROT is an algorithm that improves restarted GMRES by recycling a selected subspace of the search space from one restart of GMRES(m) to the next as well as building and recycling this outer vector space from one problem to the next (subsequent time steps i...
Dynamical ensembles equivalence in fluid mechanics
Giovanni Gallavotti
1996-05-09T23:59:59.000Z
Dissipative Euler and Navier Stokes equations are discussed with the aim of proposing several experiments apt to test the equivalence of dynamical ensembles and the chaotic hypothesis.
Lee, S.
2011-05-17T23:59:59.000Z
The process of recovering the waste in storage tanks at the Savannah River Site (SRS) typically requires mixing the contents of the tank to ensure uniformity of the discharge stream. Mixing is accomplished with one to four dual-nozzle slurry pumps located within the tank liquid. For the work, a Tank 48 simulation model with a maximum of four slurry pumps in operation has been developed to estimate flow patterns for efficient solid mixing. The modeling calculations were performed by using two modeling approaches. One approach is a single-phase Computational Fluid Dynamics (CFD) model to evaluate the flow patterns and qualitative mixing behaviors for a range of different modeling conditions since the model was previously benchmarked against the test results. The other is a two-phase CFD model to estimate solid concentrations in a quantitative way by solving the Eulerian governing equations for the continuous fluid and discrete solid phases over the entire fluid domain of Tank 48. The two-phase results should be considered as the preliminary scoping calculations since the model was not validated against the test results yet. A series of sensitivity calculations for different numbers of pumps and operating conditions has been performed to provide operational guidance for solids suspension and mixing in the tank. In the analysis, the pump was assumed to be stationary. Major solid obstructions including the pump housing, the pump columns, and the 82 inch central support column were included. The steady state and three-dimensional analyses with a two-equation turbulence model were performed with FLUENT{trademark} for the single-phase approach and CFX for the two-phase approach. Recommended operational guidance was developed assuming that local fluid velocity can be used as a measure of sludge suspension and spatial mixing under single-phase tank model. For quantitative analysis, a two-phase fluid-solid model was developed for the same modeling conditions as the single-phase model. The modeling results show that the flow patterns driven by four pump operation satisfy the solid suspension requirement, and the average solid concentration at the plane of the transfer pump inlet is about 12% higher than the tank average concentrations for the 70 inch tank level and about the same as the tank average value for the 29 inch liquid level. When one of the four pumps is not operated, the flow patterns are satisfied with the minimum suspension velocity criterion. However, the solid concentration near the tank bottom is increased by about 30%, although the average solid concentrations near the transfer pump inlet have about the same value as the four-pump baseline results. The flow pattern results show that although the two-pump case satisfies the minimum velocity requirement to suspend the sludge particles, it provides the marginal mixing results for the heavier or larger insoluble materials such as MST and KTPB particles. The results demonstrated that when more than one jet are aiming at the same position of the mixing tank domain, inefficient flow patterns are provided due to the highly localized momentum dissipation, resulting in inactive suspension zone. Thus, after completion of the indexed solids suspension, pump rotations are recommended to avoid producing the nonuniform flow patterns. It is noted that when tank liquid level is reduced from the highest level of 70 inches to the minimum level of 29 inches for a given number of operating pumps, the solid mixing efficiency becomes better since the ratio of the pump power to the mixing volume becomes larger. These results are consistent with the literature results.
Recent CFD-Related Activities at the High
Tennessee, University of
The Goal #12;Freels ,CFD Colloquium at UTK,in honor of A, J. Baker, 05/18/2010 · spent fuel re: Convert to LEU Fuel #12;Freels ,CFD Colloquium at UTK,in honor of A, J. Baker, 05/18/2010 COMSOL Models;Freels ,CFD Colloquium at UTK,in honor of A, J. Baker, 05/18/2010 COMSOL 2D Development of Fluid
Molecular Dynamics Simulation of Binary Fluid in a Nanochannel
Mullick, Shanta; Ahluwalia, P. K. [Department of Physics, Himachal Pradesh University, SummerHill, Shimla - 171005 (India); Pathania, Y. [Chitkara University, Atal Shiksha Kunj, Atal Nagar, Barotiwala, Dist Solan, Himachal Pradesh - 174103 (India)
2011-12-12T23:59:59.000Z
This paper presents the results from a molecular dynamics simulation of binary fluid (mixture of argon and krypton) in the nanochannel flow. The computational software LAMMPS is used for carrying out the molecular dynamics simulations. Binary fluids of argon and krypton with varying concentration of atom species were taken for two densities 0.65 and 0.45. The fluid flow takes place between two parallel plates and is bounded by horizontal walls in one direction and periodic boundary conditions are imposed in the other two directions. To drive the flow, a constant force is applied in one direction. Each fluid atom interacts with other fluid atoms and wall atoms through Week-Chandler-Anderson (WCA) potential. The velocity profile has been looked at for three nanochannel widths i.e for 12{sigma}, 14{sigma} and 16{sigma} and also for the different concentration of two species. The velocity profile of the binary fluid predicted by the simulations agrees with the quadratic shape of the analytical solution of a Poiseuille flow in continuum theory.
Green Algae as Model Organisms for Biological Fluid Dynamics
Goldstein, Raymond E
2014-01-01T23:59:59.000Z
In the past decade the volvocine green algae, spanning from the unicellular $Chlamydomonas$ to multicellular $Volvox$, have emerged as model organisms for a number of problems in biological fluid dynamics. These include flagellar propulsion, nutrient uptake by swimming organisms, hydrodynamic interactions mediated by walls, collective dynamics and transport within suspensions of microswimmers, the mechanism of phototaxis, and the stochastic dynamics of flagellar synchronization. Green algae are well suited to the study of such problems because of their range of sizes (from 10 $\\mu$m to several millimetres), their geometric regularity, the ease with which they can be cultured and the availability of many mutants that allow for connections between molecular details and organism-level behavior. This review summarizes these recent developments and highlights promising future directions in the study of biological fluid dynamics, especially in the context of evolutionary biology, that can take advantage of these re...
Green Algae as Model Organisms for Biological Fluid Dynamics
Raymond E. Goldstein
2014-09-08T23:59:59.000Z
In the past decade the volvocine green algae, spanning from the unicellular $Chlamydomonas$ to multicellular $Volvox$, have emerged as model organisms for a number of problems in biological fluid dynamics. These include flagellar propulsion, nutrient uptake by swimming organisms, hydrodynamic interactions mediated by walls, collective dynamics and transport within suspensions of microswimmers, the mechanism of phototaxis, and the stochastic dynamics of flagellar synchronization. Green algae are well suited to the study of such problems because of their range of sizes (from 10 $\\mu$m to several millimetres), their geometric regularity, the ease with which they can be cultured and the availability of many mutants that allow for connections between molecular details and organism-level behavior. This review summarizes these recent developments and highlights promising future directions in the study of biological fluid dynamics, especially in the context of evolutionary biology, that can take advantage of these remarkable organisms.
Simulation of spray drying in superheated steam using computational fluid dynamics
Frydman, A.; Vasseur, J.; Ducept, F.; Sionneau, M.; Moureh, J.
1999-09-01T23:59:59.000Z
This paper presents a numerical simulation and experimental validation of a spray dryer using superheated steam instead of air as drying medium, modeled with a computational fluid dynamics (CFD) code. The model describes momentum, heat and mass transfer between two phases--a discrete phase of droplets, and a continuous gas phase--through a finite volume method. For the simulation, droplet size distribution is represented by 6 discrete classes of diameter, fitting to the experimental distribution injected from the nozzle orifice, taking into account their peculiar shrinkage during drying. This model is able to predict the most important features of the dryer: fields of gas temperature and gas velocity inside the chamber, droplets trajectories and eventual deposits on to the wall. The results of simulation are compared to a pilot scale dryer, using water. In the absence of risk of power ignition in steam, the authors have tested rather high steam inlet temperature (973K), thus obtaining a high volumic efficiency. The model is validated by comparison between experimental and predicted values of temperature inside the chamber, verifying the coupling between the 3 different types of transfer without adjustment. This type of model can be used for chamber design, or scale up. Using superheated steam instead of air in a spray dryer can allow a high volumic evaporation rate (20 k.h.m{sup 3}), high energy recovery and better environment control.
Surface accumulation of spermatozoa: a fluid dynamic phenomenon
David J. Smith; John R. Blake
2010-07-13T23:59:59.000Z
Recent mathematical fluid dynamics models have shed light into an outstanding problem in reproductive biology: why do spermatozoa cells show a 'preference' for swimming near to surfaces? In this paper we review quantitative approaches to the problem, originating with the classic paper of Lord Rothschild in 1963. A recent 'boundary integral/slender body theory' mathematical model for the fluid dynamics is described, and we discuss how it gives insight into the mechanisms that may be responsible for the surface accumulation behaviour. We use the simulation model to explore these mechanisms in more detail, and discuss whether simplified models can capture the behaviour of sperm cells. The far-field decay of the fluid flow around the cell is calculated, and compared with a stresslet model. Finally we present some new findings showing how, despite having a relatively small hydrodynamic drag, the sperm cell 'head' has very significant effects on surface accumulation and trajectory.
Manish Kumar; Santi Gopal Sahu [Central Institute of Mining and Fuel Research, Combustion Section, Dhanbad (India)]. man_manna@yahoo.com
2007-12-15T23:59:59.000Z
Computer models for coal combustion are not sufficiently accurate to enable the design of pulverized coal fired furnaces or the selection of coal based on combustion behavior. Most comprehensive combustion models can predict with reasonable accuracy flow fields and heat transfer but usually with a much lesser degree of accuracy than the combustion of coal particles through char burnout. Computational fluid dynamics (CFD) modeling is recognized widely to be a cost-effective, advanced tool for optimizing the design and operating condition of the pulverized coal-fired furnaces for achieving cleaner and efficient power generation. Technologists and researchers are paying remarkable attention to CFD because of its value in the pulverized fuel fired furnace technology and its nonintrusiveness, sophistication, and ability to significantly reduce the time and expense involved in the design, optimization, trouble-shooting, and repair of power generation equipment. An attempt to study the effect of one of the operating conditions, i.e., burner tilts on coal combustion mechanisms, furnace exit gas temperature (FEGT), and heat flux distribution pattern, within the furnace has been made in this paper by modeling a 210 MW boiler using commercial CFD code FLUENT. 5 refs., 8 figs.
Dynamic Particle Coupling for GPU-based Fluid Simulation
Blanz, Volker
-vi ¯j 2 W( Pi -Pj ,h). Here pj = k( ¯j - 0) is the pressure with gas constant k and rest density 0 for modeling dynamic particle coupling solely based on individual particle contributions. This technique does and µ is the fluid viscosity constant. To model the surface tension, M¨uller et.al. [MCG03] use the so
ARBITRARY LAGRANGIAN-EULERIAN (ALE) METHODS IN COMPRESSIBLE FLUID DYNAMICS
Kurien, Susan
· . Scalar quantities (density , pressure p, specific internal energy and temperature T) are approximated Lagrangian system is numerically treated by compatible method [8, 9] conserving total energy. Several types Lagrangian-Eulerian (ALE [1]) code for simulation of problems in compressible fluid dynamics and plasma
COMPUTATIONAL FLUID DYNAMICS MODELING OF SOLID OXIDE FUEL CELLS
COMPUTATIONAL FLUID DYNAMICS MODELING OF SOLID OXIDE FUEL CELLS Ugur Pasaogullari and Chao-dimensional model has been developed to simulate solid oxide fuel cells (SOFC). The model fully couples current density operation. INTRODUCTION Solid oxide fuel cells (SOFC) are among possible candidates
Fluids as Dynamic Templates for Cytoskeletal Proteins in Plant Cells
J. T. Lofthouse
2008-07-12T23:59:59.000Z
The Dynamic Template model of biological cell membranes and the cytoplasm as spatially organised fluid layers is extended to plant cells, and is shown to offer a feasible shear driven mechanism for the co-alignment of internal and external fibres observed during growth and tropic responses
Revised: Thursday, February 25, 1999 Dynamics of osmotic fluid flow
Oster, George
Revised: Thursday, February 25, 1999 Dynamics of osmotic fluid flow George Oster Departments The classical thermodynamic treatment of osmotic pressure is quite sufficient to describe equilibrium situations can be quite useful when thinking about osmotic flow in unfamiliar situations. The equilibrium
Air Ingress Benchmarking with Computational Fluid Dynamics Analysis
Air Ingress Benchmarking with Computational Fluid Dynamics Analysis Andrew C. Kadak Department District Beijing, China September 22-24, 2004 Abstract Air ingress accident is a complicated accident scenario is compounded by multiple physical phenomena that are involved in the air ingress event
Air Ingress Benchmarking with Computational Fluid Dynamics Analysis
1 Air Ingress Benchmarking with Computational Fluid Dynamics Analysis Tieliang Zhai Professor by the US Nuclear Regulatory Commission #12;2 Air Ingress Accident Objectives and Overall Strategy: Depresurization Pure Diffusion Natural Convection Challenging: Natural convection Multi-component Diffusion (air
PETER LEE OLSON Present Position: Professor of Geophysical Fluid Dynamics
Olson, Peter L.
Power Plant Siting Program Scientific Steering Panel, NASA GRM mission University Corporation of California, Berkeley, California M.A. Geophysics, June 1974, University of California, Berkeley, California B of California, Berkeley (1980) Assistant Professor of Geophysical Fluid Dynamics, Johns Hopkins University
PETER LEE OLSON Present Position: Professor of Geophysical Fluid Dynamics
Olson, Peter L.
Union, Tectonophysics Section Scientific Advisory Board, Maryland Power Plant Siting Program Scientific of California, Berkeley, California M.A. Geophysics, June 1974, University of California, Berkeley, California B of California, Berkeley (1980) Assistant Professor of Geophysical Fluid Dynamics, Johns Hopkins University
Proceedings of ASME-FED 2006 2006 ASME Fluids Engineering Summer Conference
Smith, Barton L.
Proceedings of ASME-FED 2006 2006 ASME Fluids Engineering Summer Conference Miami, USA, July 17 of the INL model and to develop benchmark databases for CFD (Computational Fluid Dynamics) code assessment by ASME #12;through two perforated plates placed in line to suppress separa- tion and any pulsations
Marcello Sega; Mauro Sbragaglia; Sofia Sergeevna Kantorovich; Alexey Olegovich Ivanov
2014-02-19T23:59:59.000Z
Complex fluid-fluid interfaces featuring mesoscale structures with adsorbed particles are key components of newly designed materials which are continuously enriching the field of soft matter. Simulation tools which are able to cope with the different scales characterizing these systems are fundamental requirements for efficient theoretical investigations. In this paper we present a novel simulation method, based on the approach of Ahlrichs and D\\"unweg [Ahlrichs and D\\"unweg, Int. J. Mod. Phys. C, 1998, 9, 1429], that couples the "Shan-Chen" multicomponent Lattice Boltzmann technique to off-lattice molecular dynamics to simulate efficiently complex fluid-fluid interfaces. We demonstrate how this approach can be used to study a wide class of challenging problems. Several examples are given, with an accent on bicontinuous phases formation in polyelectrolyte solutions and ferrofluid emulsions. We also show that the introduction of solvation free energies in the particle-fluid interaction unveils the hidden, multiscale nature of the particle-fluid coupling, allowing to treat symmetrically (and interchangeably) the on-lattice and off-lattice components of the system.
fjYTiYTvl/f^ Ris-R-674(EN) Optics and Fluid Dynamics
fjYTiYTvl/f^ Risø-R-674(EN) Optics and Fluid Dynamics Department Annual Progress Report for 1992 #12;Optics and Fluid Dynamics Department AnnualProgressReport for1992 Edited by L. Lading, JJ. Lynov in the Optics and Fluid Dynamics Department is performed within two sections- The Optics Section has activities
Astronomy 202: Astrophysical Gas Dynamics LL = Fluid Mechanics by Landau & Lifshitz
Wurtele, Jonathan
Astronomy 202: Astrophysical Gas Dynamics LL = Fluid Mechanics by Landau & Lifshitz PP = Plasma Fluid Dynamics by D. J. Tritton You should start by reading the Feynman Lectures Vol II, Ch 40 & 41 (Shu Ch. 1) 2. Equations of Gas Dynamics: neutral ideal fluids (LL Ch. 1; esp. §1,2,5,6,7,8,10; Shu Ch
Computational Fluid Dynamics Study of Aerosol Transport and Deposition Mechanisms
Tang, Yingjie
2012-07-16T23:59:59.000Z
OF PHILOSOPHY Approved by: Co-Chairs of Committee, Bing Guo Devesh Ranjan Committee Members, Hamn-Ching Chen Qi Ying Head of Department, Jerald Caton May 2012 Major Subject: Mechanical Engineering iii ABSTRACT Computational Fluid Dynamics... as the spatial region in which the flow field and the particle transport/deposition are to be resolved (ANSYS, 2008), and numerically speaking, it would be ?bounded? by various types of wall surfaces (with no- slip flow boundary condition) or non-wall surfaces...
Recent progress and challenges in exploiting graphics processors in computational fluid dynamics
Niemeyer, Kyle E
2014-01-01T23:59:59.000Z
The progress made in accelerating simulations of fluid flow using GPUs, and the challenges that remain, are surveyed. The review first provides an introduction to GPU computing and programming, and discusses various considerations for improved performance. Case studies comparing the performance of CPU- and GPU- based solvers for the Laplace and incompressible Navier-Stokes equations are performed in order to demonstrate the potential improvement even with simple codes. Recent efforts to accelerate CFD simulations using GPUs are reviewed for laminar, turbulent, and reactive flow solvers. Also, GPU implementations of the lattice Boltzmann method are reviewed. Finally, recommendations for implementing CFD codes on GPUs are given and remaining challenges are discussed, such as the need to develop new strategies and redesign algorithms to enable GPU acceleration.
CFD modeling of entrained-flow coal gasifiers with improved physical and chemical sub-models
Ma, J.; Zitney, S.
2012-01-01T23:59:59.000Z
Optimization of an advanced coal-fired integrated gasification combined cycle system requires an accurate numerical prediction of gasifier performance. While the turbulent multiphase reacting flow inside entrained-flow gasifiers has been modeled through computational fluid dynamic (CFD), the accuracy of sub-models requires further improvement. Built upon a previously developed CFD model for entrained-flow gasification, the advanced physical and chemical sub-models presented here include a moisture vaporization model with consideration of high mass transfer rate, a coal devolatilization model with more species to represent coal volatiles and heating rate effect on volatile yield, and careful selection of global gas phase reaction kinetics. The enhanced CFD model is applied to simulate two typical oxygen-blown entrained-flow configurations including a single-stage down-fired gasifier and a two-stage up-fired gasifier. The CFD results are reasonable in terms of predicted carbon conversion, syngas exit temperature, and syngas exit composition. The predicted profiles of velocity, temperature, and species mole fractions inside the entrained-flow gasifier models show trends similar to those observed in a diffusion-type flame. The predicted distributions of mole fractions of major species inside both gasifiers can be explained by the heterogeneous combustion and gasification reactions and the homogeneous gas phase reactions. It was also found that the syngas compositions at the CFD model exits are not in chemical equilibrium, indicating the kinetics for both heterogeneous and gas phase homogeneous reactions are important. Overall, the results achieved here indicate that the gasifier models reported in this paper are reliable and accurate enough to be incorporated into process/CFD co-simulations of IGCC power plants for systemwide design and optimization.
Bonneville Project: CFD of the Spillway Tailrace
Rakowski, Cynthia L.; Serkowski, John A.; Richmond, Marshall C.; Romero Gomez, Pedro DJ
2012-11-19T23:59:59.000Z
US Army Corps of Engineers, Portland District (CENWP) operates the Bonneville Lock and Dam Project on the Columbia River. High spill flows that occurred during 2011 moved a large volume of rock from downstream of the spillway apron to the stilling basin and apron. Although 400 cubic yards of rocks were removed from the stilling basin, there are still large volumes of rock downstream of the apron that could, under certain flow conditions, move upstream into the stilling basin. CENWP is investigating operational changes that could be implemented to minimize future movement of rock into the stilling basin. A key analysis tool to develop these operational changes is a computational fluid dynamics (CFD) model of the spillway. A free-surface CFD model of the Bonneville spillway tailrace was developed and applied for four flow scenarios. These scenarios looked at the impact of flow volume and flow distribution on tailrace hydraulics. The simulation results showed that areas of upstream flow existed near the river bed downstream of the apron, on the apron, and within the stilling basin for all flows. For spill flows of 300 kcfs, the cross-stream and downstream extent of the recirculation zones along Cascade and Bradford Island was very dependent on the spill pattern. The center-loaded pattern had much larger recirculation zones than the flat or bi-modal pattern. The lower flow (200 kcfs) with a flat pattern had a very large recirculation zone that extended half way across the channel near the river bed. A single flow scenario (300 kcfs of flow in a relatively flat spill pattern) was further interrogated using Lagrangian particle tracking. The tracked particles (with size and mass) showed the upstream movement of sediments onto the concrete apron and against the vertical wall between the apron and the stilling basin from seed locations downstream of the apron and on the apron.
Zevenhoven, Ron
Introduction to Computational Fluid Dynamics 424512 E #2 - rz maj 2015 Åbo Akademi Univ - Chemical Engineering Thermal and Flow Engineering - Piispankatu 8, 20500 Turku 1/70 Introduction to Computational Fluid.zevenhoven@abo.fi Introduction to Computational Fluid Dynamics 424512 E #2 - rz maj 2015 Åbo Akademi Univ - Chemical Engineering
A STUDY OF COMPUTATIONAL FLUID DYNAMICS APPLIED TO ROOM AIR FLOW
for supplying me a copy of his three-dimensional, laminar, constant density fluid flow computer program, whichi A STUDY OF COMPUTATIONAL FLUID DYNAMICS APPLIED TO ROOM AIR FLOW By JAMES W. WEATHERS Bachelor of the requirements for the Degree of MASTER OF SCIENCE May, 1992 #12;ii A STUDY OF COMPUTATIONAL FLUID DYNAMICS
In, Wang-Kee; Chun, Tae-Hyun; Shin, Chang-Hwan; Oh, Dong-Seok [Korea Atomic Energy Research Institute, 1045 Daedeokdaero, Yuseong-Gu, Daejeon, Korea 305-353 (Korea, Republic of)
2007-07-01T23:59:59.000Z
A computational fluid dynamics (CFD) analysis has been performed to investigate a flow-mixing and heat-transfer enhancement caused by a mixing-vane spacer in a LWR fuel assembly which is a rod bundle. This paper presents the CFD simulations of a flow mixing and heat transfer in a fully heated 5x5 array of a rod bundle with a split-vane and hybrid-vane spacer. The CFD prediction at a low Reynolds number of 42,000 showed a reasonably good agreement of the initial heat transfer enhancement with the measured one for a partially heated experiment using a similar spacer structure. The CFD simulation also predicted the decay rate of a normalized Nusselt number downstream of the split-vane spacer which agrees fairly well with those of the experiment and the correlation. The CFD calculations for the split vane and hybrid vane at the LWR operating conditions(Re = 500,000) predicted hot fuel spots in a streaky structure downstream of the spacer, which occurs due to the secondary flow occurring in an opposite direction near the fuel rod. However, the split-vane and hybrid-vane spacers are predicted to significantly enhance the overall heat transfer of a LWR nuclear fuel assembly. (authors)
Head Loss Evaluation in a PWR Reactor Vessel Using CFD Analysis
Ji Hwan Jeong; Jong Pil Park [School of Mechanical Engineering, Pusan National University, Enesys Jangjeon-dong, Geumjeong-gu, Busan (Korea, Republic of); Byoung-Sub Han [Jangdae-dong, Yusong-gu, Daejeon (Korea, Republic of)
2006-07-01T23:59:59.000Z
Nuclear vendors and utilities perform lots of simulations and analyses in order to ensure the safe operation of nuclear power plants (NPPs). In general, the simulations are carried out using vendor-specific design codes and best-estimate system analysis codes and most of them were developed based on 1-dimensional lumped parameter models. During the past decade, however, computers, parallel computation methods, and 3-dimensional computational fluid dynamics (CFD) codes have been dramatically enhanced. It is believed to be beneficial to take advantage of advanced commercial CFD codes in safety analysis and design of NPPs. The present work aims to analyze the flow distribution in downcomer and lower plenum of Korean standard nuclear power plants (KSNPs) using STAR-CD. The lower plenum geometry of a PWR is very complicated since there are so many reactor internals, which hinders in CFD analysis for real reactor geometry up to now. The present work takes advantage of 3D CAD model so that real geometry of lower plenum is used. The results give a clear figure about flow fields in the reactor vessel, which is one of major safety concerns. The calculated pressure drop across downcomer and lower plenum appears to be in good agreement with the data in engineering calculation note. A algorithm which can evaluate head loss coefficient which is necessary for thermal-hydraulic system code running was suggested based on this CFD analysis results. (authors)
Leishear, R.; Poirier, M.; Lee, S.; Fowley, M.
2012-06-26T23:59:59.000Z
This paper documents testing methods, statistical data analysis, and a comparison of experimental results to CFD models for blending of fluids, which were blended using a single pump designed with dual opposing nozzles in an eight foot diameter tank. Overall, this research presents new findings in the field of mixing research. Specifically, blending processes were clearly shown to have random, chaotic effects, where possible causal factors such as turbulence, pump fluctuations, and eddies required future evaluation. CFD models were shown to provide reasonable estimates for the average blending times, but large variations -- or scatter -- occurred for blending times during similar tests. Using this experimental blending time data, the chaotic nature of blending was demonstrated and the variability of blending times with respect to average blending times were shown to increase with system complexity. Prior to this research, the variation in blending times caused discrepancies between CFD models and experiments. This research addressed this discrepancy, and determined statistical correction factors that can be applied to CFD models, and thereby quantified techniques to permit the application of CFD models to complex systems, such as blending. These blending time correction factors for CFD models are comparable to safety factors used in structural design, and compensate variability that cannot be theoretically calculated. To determine these correction factors, research was performed to investigate blending, using a pump with dual opposing jets which re-circulate fluids in the tank to promote blending when fluids are added to the tank. In all, eighty-five tests were performed both in a tank without internal obstructions and a tank with vertical obstructions similar to a tube bank in a heat exchanger. These obstructions provided scale models of vertical cooling coils below the liquid surface for a full scale, liquid radioactive waste storage tank. Also, different jet diameters and different horizontal orientations of the jets were investigated with respect to blending. Two types of blending tests were performed. The first set of eighty-one tests blended small quantities of tracer fluids into solution. Data from these tests were statistically evaluated to determine blending times for the addition of tracer solution to tanks, and blending times were successfully compared to Computational Fluid Dynamics (CFD) models. The second set of four tests blended bulk quantities of solutions of different density and viscosity. For example, in one test a quarter tank of water was added to a three quarters of a tank of a more viscous salt solution. In this case, the blending process was noted to significantly change due to stratification of fluids, and blending times increased substantially. However, CFD models for stratification and the variability of blending times for different density fluids was not pursued, and further research is recommended in the area of blending bulk quantities of fluids. All in all, testing showed that CFD models can be effectively applied if statistically validated through experimental testing, but in the absence of experimental validation CFD model scan be extremely misleading as a basis for design and operation decisions.
On preparation of viscous pore fluids for dynamic centrifuge modelling
Adamidis, O.; Madabhushi, S. P. G.
2014-11-21T23:59:59.000Z
dynamic cen- trifuge tests, the use of water as pore fluid can limit the generation of excess pore pressures in sand formations below gravel embankments, lowering the recorded crest settlement signif- icantly. Chian and Madabhushi [2010] exam- ined... with changing 4 1.2 1.6 2 2.4 2.8 3.2 0 40 80 120 160 200 Concentration [%] V is co si ty [m P a · s] measurements at 20?C best fit (8th order) best fit (power law) Stewart et al. [1998] Figure 2: Viscosity change with concentration 1.2 1.6 2 2.4 2.8 3.2 1...
Processes and Procedures for Application of CFD to Nuclear Reactor Safety Analysis
Richard W. Johnson; Richard R. Schultz; Patrick J. Roache; Ismail B. Celik; William D. Pointer; Yassin A. Hassan
2006-09-01T23:59:59.000Z
Traditionally, nuclear reactor safety analysis has been performed using systems analysis codes such as RELAP5, which was developed at the INL. However, goals established by the Generation IV program, especially the desire to increase efficiency, has lead to an increase in operating temperatures for the reactors. This increase pushes reactor materials to operate towards their upper temperature limits relative to structural integrity. Because there will be some finite variation of the power density in the reactor core, there will be a potential for local hot spots to occur in the reactor vessel. Hence, it has become apparent that detailed analysis will be required to ensure that local ‘hot spots’ do not exceed safety limits. It is generally accepted that computational fluid dynamics (CFD) codes are intrinsically capable of simulating fluid dynamics and heat transport locally because they are based on ‘first principles.’ Indeed, CFD analysis has reached a fairly mature level of development, including the commercial level. However, CFD experts are aware that even though commercial codes are capable of simulating local fluid and thermal physics, great care must be taken in their application to avoid errors caused by such things as inappropriate grid meshing, low-order discretization schemes, lack of iterative convergence and inaccurate time-stepping. Just as important is the choice of a turbulence model for turbulent flow simulation. Turbulence models model the effects of turbulent transport of mass, momentum and energy, but are not necessarily applicable for wide ranges of flow types. Therefore, there is a well-recognized need to establish practices and procedures for the proper application of CFD to simulate flow physics accurately and establish the level of uncertainty of such computations. The present document represents contributions of CFD experts on what the basic practices, procedures and guidelines should be to aid CFD analysts to obtain accurate estimates of the flow and energy transport as applied to nuclear reactor safety. However, it is expected that these practices and procedures will require updating from time to time as research and development affect them or replace them with better procedures. The practices and procedures are categorized into five groups. These are: 1.Code Verification 2.Code and Calculation Documentation 3.Reduction of Numerical Error 4.Quantification of Numerical Uncertainty (Calculation Verification) 5.Calculation Validation. These five categories have been identified from procedures currently required of CFD simulations such as those required for publication of a paper in the ASME Journal of Fluids Engineering and from the literature such as Roache [1998]. Code verification refers to the demonstration that the equations of fluid and energy transport have been correctly coded in the CFD code. Code and calculation documentation simply means that the equations and their discretizations, etc., and boundary and initial conditions used to pose the fluid flow problem are fully described in available documentation. Reduction of numerical error refers to practices and procedures to lower numerical errors to negligible or very low levels as is reasonably possible (such as avoiding use of first-order discretizations). The quantification of numerical uncertainty is also known as calculation verification. This means that estimates are made of numerical error to allow the characterization of the numerical
Battiste, Richard L. (Oak Ridge, TN)
2007-12-25T23:59:59.000Z
Methods and apparatus are described for characterizing the temporal-spatial properties of a dynamic fluid front within a mold space while the mold space is being filled with fluid. A method includes providing a mold defining a mold space and having one or more openings into the mold space; heating a plurality of temperature sensors that extend into the mold space; injecting a fluid into the mold space through the openings, the fluid experiencing a dynamic fluid front while filling the mold space with the fluid; and characterizing temporal-spatial properties of the dynamic fluid front by monitoring a temperature of each of the plurality of heated temperature sensors while the mold space is being filled with the fluid. An apparatus includes a mold defining a mold space; one or more openings for introducing a fluid into the mold space and filling the mold space with the fluid, the fluid experiencing a dynamic fluid front while filling the mold space; a plurality of heated temperature sensors extending into the mold space; and a computer coupled to the plurality of heated temperature sensors for characterizing the temporal-spatial properties of the dynamic fluid front.
Battiste, Richard L
2013-12-31T23:59:59.000Z
Methods and apparatus are described for characterizing the temporal-spatial properties of a dynamic fluid front within a mold space while the mold space is being filled with fluid. A method includes providing a mold defining a mold space and having one or more openings into the mold space; heating a plurality of temperature sensors that extend into the mold space; injecting a fluid into th emold space through the openings, the fluid experiencing a dynamic fluid front while filling the mold space with a fluid; and characterizing temporal-spatial properties of the dynamic fluid front by monitoring a termperature of each of the plurality of heated temperature sensors while the mold space is being filled with the fluid. An apparatus includes a mold defining a mold space; one or more openings for introducing a fluid into th emold space and filling the mold space with the fluid, the fluid experiencing a dynamic fluid front while filling the mold space; a plurality of heated temperature sensors extending into the mold space; and a computer coupled to the plurality of heated temperature sensors for characterizing the temporal-spatial properties of the dynamic fluid front.
CFD Simulations of Joint Urban Atmospheric Dispersion Field Study
Lee, R; Humphreys III, T; Chan, S
2004-06-17T23:59:59.000Z
The application of Computational Fluid Dynamics (CFD) to the understanding of urban wind flow and dispersion processes has gained increasing attention over recent years. While many of the simpler dispersion models are based on a set of prescribed meteorology to calculate dispersion, the CFD approach has the ability of coupling the wind field to dispersion processes. This has distinct advantages when very detailed results are required, such as for the case where the releases occur around buildings and within urban areas. CFD also has great flexibility as a testbed for turbulence models, which has important implications for atmospheric dispersion problems. In the spring of 2003, a series of dispersion field experiments (Joint Urban 2003) were conducted at Oklahoma City (Allwine, et. al, 2004). These experiments were complimentary to the URBAN 2000 field studies at Salt Lake City (Shinn, et. al, 2000) in that they will provide a second set of comprehensive field data for evaluation of CFD as well as for other dispersion models. In contrast to the URBAN 2000 experiments that were conducted entirely at night, these new field studies took place during both daytime and nighttime thus including the possibility of convective as well as stable atmospheric conditions. Initially several CFD modeling studies were performed to provide guidance for the experimental team in the selection of release sites and in the deployment of wind and concentration sensors. Also, while meteorological and concentration measurements were taken over the greater Oklahoma City urban area, our CFD calculations were focused on the near field of the release point. The proximity of the source to a large commercial building and to the neighboring buildings several of which have multistories, present a significant challenge even for CFD calculations involving grid resolutions as fine as 1 meter. A total of 10 Intensive Observations Periods (IOP's) were conducted within the 2003 field experiments. SF6 releases in the form of puffs or continuous sources were disseminated over 6 daytime and 4 nighttime episodes. Many wind and concentration sensors were used to provide wind and SF6 data over both long and short time-averaging periods. In addition to the usual near surface measurements, data depicting vertical profiles of wind and concentrations adjacent to the outside walls of several buildings were also taken. Also of interest were observations of the trajectory of balloons that were deployed close to the tracer release area. Many of the balloons released exhibit extremely quick ascents up from ground level to the top of buildings, thus implying highly convective conditions. In this paper we will present some simulations that were performed during the planning of the field experiments. The calculations were based on two possible release sites at the intersections of Sheridan and Robinson, and Broadway and Sheridan. These results provided initial information on flow and dispersion patterns, which could be used to guide optimal placement of sensors at appropriate locations. We will also discuss results of more recent simulations for several releases in which reliable data is available. These simulations will be compared with the near field data taken from the wind sensors as well as the time-averaged data from the concentration sensors. Among the other topics discussed are initial and boundary conditions used in the simulations, adaptation of building GIS data for CFD modeling and analysis of field data.
Applying uncertainty quantification to multiphase flow computational fluid dynamics
Gel, A.; Garg, R.; Tong, C.; Shahnam, M.; Guenther, C.
2013-07-01T23:59:59.000Z
Multiphase computational fluid dynamics plays a major role in design and optimization of fossil fuel based reactors. There is a growing interest in accounting for the influence of uncertainties associated with physical systems to increase the reliability of computational simulation based engineering analysis. The U.S. Department of Energy's National Energy Technology Laboratory (NETL) has recently undertaken an initiative to characterize uncertainties associated with computer simulation of reacting multiphase flows encountered in energy producing systems such as a coal gasifier. The current work presents the preliminary results in applying non-intrusive parametric uncertainty quantification and propagation techniques with NETL's open-source multiphase computational fluid dynamics software MFIX. For this purpose an open-source uncertainty quantification toolkit, PSUADE developed at the Lawrence Livermore National Laboratory (LLNL) has been interfaced with MFIX software. In this study, the sources of uncertainty associated with numerical approximation and model form have been neglected, and only the model input parametric uncertainty with forward propagation has been investigated by constructing a surrogate model based on data-fitted response surface for a multiphase flow demonstration problem. Monte Carlo simulation was employed for forward propagation of the aleatory type input uncertainties. Several insights gained based on the outcome of these simulations are presented such as how inadequate characterization of uncertainties can affect the reliability of the prediction results. Also a global sensitivity study using Sobol' indices was performed to better understand the contribution of input parameters to the variability observed in response variable.
Scaling studies and conceptual experiment designs for NGNP CFD assessment
D. M. McEligot; G. E. McCreery
2004-11-01T23:59:59.000Z
The objective of this report is to document scaling studies and conceptual designs for flow and heat transfer experiments intended to assess CFD codes and their turbulence models proposed for application to prismatic NGNP concepts. The general approach of the project is to develop new benchmark experiments for assessment in parallel with CFD and coupled CFD/systems code calculations for the same geometry. Two aspects of the complex flow in an NGNP are being addressed: (1) flow and thermal mixing in the lower plenum ("hot streaking" issue) and (2) turbulence and resulting temperature distributions in reactor cooling channels ("hot channel" issue). Current prismatic NGNP concepts are being examined to identify their proposed flow conditions and geometries over the range from normal operation to decay heat removal in a pressurized cooldown. Approximate analyses have been applied to determine key non-dimensional parameters and their magnitudes over this operating range. For normal operation, the flow in the coolant channels can be considered to be dominant turbulent forced convection with slight transverse property variation. In a pressurized cooldown (LOFA) simulation, the flow quickly becomes laminar with some possible buoyancy influences. The flow in the lower plenum can locally be considered to be a situation of multiple hot jets into a confined crossflow -- with obstructions. Flow is expected to be turbulent with momentumdominated turbulent jets entering; buoyancy influences are estimated to be negligible in normal full power operation. Experiments are needed for the combined features of the lower plenum flows. Missing from the typical jet experiments available are interactions with nearby circular posts and with vertical posts in the vicinity of vertical walls - with near stagnant surroundings at one extreme and significant crossflow at the other. Two types of heat transfer experiments are being considered. One addresses the "hot channel" problem, if necessary. The second type will treat heated jets entering a model plenum. Unheated MIR (Matched-Index-of-Refraction) experiments are first steps when the geometry is complicated. One does not want to use a computational technique which will not even handle constant properties properly. The purpose of the fluid dynamics experiments is to develop benchmark databases for the assessment of CFD solutions of the momentum equations, scalar mixing and turbulence models for typical NGNP plenum geometries in the limiting case of negligible buoyancy and constant fluid properties. As indicated by the scaling studies, in normal full power operation of a typical NGNP conceptual design, buoyancy influences should be negligible in the lower plenum. The MIR experiment will simulate flow features of the paths of jets as they mix in flowing through the array of posts in a lower plenum en route to the single exit duct. Conceptual designs for such experiments are described.
Climate dynamics and fluid mechanics: Natural variability and related uncertainties
Michael Ghil; Mickaël D. Chekroun; Eric Simonnet
2010-06-15T23:59:59.000Z
The purpose of this review-and-research paper is twofold: (i) to review the role played in climate dynamics by fluid-dynamical models; and (ii) to contribute to the understanding and reduction of the uncertainties in future climate-change projections. To illustrate the first point, we focus on the large-scale, wind-driven flow of the mid-latitude oceans which contribute in a crucial way to Earth's climate, and to changes therein. We study the low-frequency variability (LFV) of the wind-driven, double-gyre circulation in mid-latitude ocean basins, via the bifurcation sequence that leads from steady states through periodic solutions and on to the chaotic, irregular flows documented in the observations. This sequence involves local, pitchfork and Hopf bifurcations, as well as global, homoclinic ones. The natural climate variability induced by the LFV of the ocean circulation is but one of the causes of uncertainties in climate projections. Another major cause of such uncertainties could reside in the structural instability in the topological sense, of the equations governing climate dynamics, including but not restricted to those of atmospheric and ocean dynamics. We propose a novel approach to understand, and possibly reduce, these uncertainties, based on the concepts and methods of random dynamical systems theory. As a very first step, we study the effect of noise on the topological classes of the Arnol'd family of circle maps, a paradigmatic model of frequency locking as occurring in the nonlinear interactions between the El Nino-Southern Oscillations (ENSO) and the seasonal cycle. It is shown that the maps' fine-grained resonant landscape is smoothed by the noise, thus permitting their coarse-grained classification. This result is consistent with stabilizing effects of stochastic parametrization obtained in modeling of ENSO phenomenon via some general circulation models.
Pseudorapidity correlations in heavy ion collisions from viscous fluid dynamics
Akihiko Monnai; Bjoern Schenke
2015-09-16T23:59:59.000Z
We demonstrate by explicit calculations in 3+1 dimensional viscous relativistic fluid dynamics how two-particle pseudorapidity correlation functions in heavy ion collisions at the LHC and RHIC depend on the number of particle producing sources and the transport properties of the produced medium. In particular, we present results for the Legendre coefficients of the two-particle pseudorapidity correlation function in Pb+Pb collisions at 2760 GeV and Au+Au collisions at 200 GeV from viscous hydrodynamics with three dimensionally fluctuating initial conditions. Our results suggest that these coefficients provide important constraints on initial state fluctuations and the transport properties of the quark gluon plasma.
Pseudorapidity correlations in heavy ion collisions from viscous fluid dynamics
Monnai, Akihiko
2015-01-01T23:59:59.000Z
We demonstrate by explicit calculations in 3+1 dimensional viscous relativistic fluid dynamics how two-particle pseudorapidity correlation functions in heavy ion collisions at the LHC and RHIC depend on the number of particle producing sources and the transport properties of the produced medium. In particular, we present results for the Legendre coefficients of the two-particle pseudorapidity correlation function in Pb+Pb collisions at 2760 GeV and Au+Au collisions at 200 GeV from viscous hydrodynamics with three dimensionally fluctuating initial conditions. Our results suggest that these coefficients provide important constraints on initial state fluctuations and the transport properties of the quark gluon plasma.
Fluid dynamics of aortic root dilation in Marfan syndrome
Querzoli, Giorgio; Espa, Stefania; Costantini, Martina; Sorgini, Francesca
2014-01-01T23:59:59.000Z
Aortic root dilation and propensity to dissection are typical manifestations of the Marfan Syndrome (MS), a genetic defect leading to the degeneration of the elastic fibres. Dilation affects the structure of the flow and, in turn, altered flow may play a role in vessel dilation, generation of aneurysms, and dissection. The aim of the present work is the investigation in-vitro of the fluid dynamic modifications occurring as a consequence of the morphological changes typically induced in the aortic root by MS. A mock-loop reproducing the left ventricle outflow tract and the aortic root was used to measure time resolved velocity maps on a longitudinal symmetry plane of the aortic root. Two dilated model aortas, designed to resemble morphological characteristics typically observed in MS patients, have been compared to a reference, healthy geometry. The aortic model was designed to quantitatively reproduce the change of aortic distensibility caused by MS. Results demonstrate that vorticity released from the valve ...
Platfoot, J.H.; Wendel, M.W.; Williams, P.T.
1996-10-01T23:59:59.000Z
This report describes the simulation of the dispersion and dilution of dissolved or finely suspended contaminants entering the Clinch river from White Oak Creek. The work is accomplished through the application of a commercial computational fluid dynamics (CFD) solver. This study assumes that contaminants originating in the White Oak Creed watershed, which drains Oak Ridge National Laboratory, will eventually reach the mouth of White Oak Creek and be discharged into the clinch River. The numerical model was developed to support the analysis of the off-site consequences of releases from the ORNL liquid low-level waste system. The system contains storage tanks and transfer lines in Bethel Valley and Melton Valley. Under certain failure modes, liquid low-level waste could be released to White Oak Creek or Melton Branch to White Oak Creek and eventually be discharged to the Clinch River. Since the Clinch River has unrestricted access by the public and water usage from the Clinch River is not controlled by the Department of Energy, such a liquid low-level waste spill would create the possibility of public exposure to the contaminant. This study is limited to the dispersion of the contaminants downstream of the confluence of White Oak Creek.
Baosheng Jin; Rui Xiao; Zhongyi Deng; Qilei Song [Southeast University (China). Key Laboratory of Clean Coal Power Generation and Combustion Technology of Ministry of Education
2009-07-01T23:59:59.000Z
To concentrate CO{sub 2} in combustion processes by efficient and energy-saving ways is a first and very important step for its sequestration. Chemical looping combustion (CLC) could easily achieve this goal. A chemical-looping combustion system consists of a fuel reactor and an air reactor. Two reactors in the form of interconnected fluidized beds are used in the process: (1) a fuel reactor where the oxygen carrier is reduced by reaction with the fuel, and (2) an air reactor where the reduced oxygen carrier from the fuel reactor is oxidized with air. The outlet gas from the fuel reactor consists of CO{sub 2} and H{sub 2}O, while the outlet gas stream from the air reactor contains only N{sub 2} and some unused O{sub 2}. The water in combustion products can be easily removed by condensation and pure carbon dioxide is obtained without any loss of energy for separation. Until now, there is little literature about mathematical modeling of chemical-looping combustion using the computational fluid dynamics (CFD) approach. In this work, the reaction kinetic model of the fuel reactor (CaSO{sub 4}+ H{sub 2}) is developed by means of the commercial code FLUENT and the effects of partial pressure of H{sub 2} (concentration of H{sub 2}) on chemical looping combustion performance are also studied. The results show that the concentration of H{sub 2} could enhance the CLC performance.
Infiltration Heat Recovery in Building Walls: Computational Fluid Dynamics Investigations Results
. In this study, Computational Fluid Dynamics was used to calculate infiltration heat recovery under a rangeLBNL-51324 Infiltration Heat Recovery in Building Walls: Computational Fluid Dynamics that conduction heat loss (or gain) through walls is independent of air infiltration heat loss (or gain). During
Handbook of Mathematical Fluid Dynamics, Volume 2 Edited by S. Friedlander and D. Serre
Renardy, Yuriko
Handbook of Mathematical Fluid Dynamics, Volume 2 Edited by S. Friedlander and D. Serre) _______________________________________________________________________ YES! Please send me ______ copy(ies) of the Handbook of Mathematical Fluid Dynamics, Volume 2, edited Department, P.O. Box 103, 1000 AC Amsterdam, The Netherlands Email: a.deelen@elsevier.com #12;Handbook
A Simple Interface to Computational Fluid Dynamics Programs for Building Environment Simulations
Chen, Qingyan "Yan"
A Simple Interface to Computational Fluid Dynamics Programs for Building Environment Simulations for architects and HVAC engineers to simulate airflows in and around buildings by Computational Fluid Dynamics Charles R. Broderick III Qingyan Chen Building Technology Program Massachusetts Institute of Technology
Optics and Fluid Dynamics Ris-R-1157(EN) Annual Progress Report for 1999
Optics and Fluid Dynamics Risø-R-1157(EN) Department Annual Progress Report for 1999 Edited by S;2 Risø-R-1157(EN) Abstract The Optics and Fluid Dynamics Department performs basic and applied research within the three programmes: (1) optical materials, (2) optical diagnostics and information processing
Optics and Fluid Dynamics Ris-R-1227(EN) Annual Progress Report for 2000
Optics and Fluid Dynamics Risø-R-1227(EN) Department Annual Progress Report for 2000 Edited by S;2 Risø-R-1227(EN) Abstract The Optics and Fluid Dynamics Department performs basic and applied research within three scientific programmes: (1) optical materials, (2) optical diagnostics and information
Optics and Fluid Dynamics Ris-R-1100(EN) Annual Progress Report for 1998
Optics and Fluid Dynamics Risø-R-1100(EN) Department Annual Progress Report for 1998 Edited by S May 1999 #12;2 Risø-R-1100(EN) Abstract Research in the Optics and Fluid Dynamics Department has been performed within the following three programme areas: (1) optical materials, (2) optical diagnostics
Structure and dynamics of mangetorheological fluids confined in microfluidic devices
Haghgooie, Ramin
2006-01-01T23:59:59.000Z
Microfluidic devices and magnetorheological (MR) fluids have been two areas of intense research for several years. Traditionally, these two fields have remained separated from one another by scale. MR fluids are best known ...
On the dynamics of magnetic fluids in magnetic resonance imaging
Cantillon-Murphy, Pádraig J
2008-01-01T23:59:59.000Z
The hydrodynamics of magnetic fluids, often termed ferrofluids, has been an active area of research since the mid 1960s. However, it is only in the past twenty years that these fluids have begun to be used in magnetic ...
CFD Modeling for Mercury Control Technology
Madsen, J.I.
2006-12-01T23:59:59.000Z
Compliance with the Clean Air Mercury Rule will require implementation of dedicated mercury control solutions at a significant portion of the U.S. coal-fired utility fleet. Activated Carbon Injection (ACI) upstream of a particulate control device (ESP or baghouse) remains one of the most promising near-term mercury control technologies. The DOE/NETL field testing program has advanced the understanding of mercury control by ACI, but a persistent need remains to develop predictive models that may improve the understanding and practical implementation of this technology. This presentation describes the development of an advanced model of in-flight mercury capture based on Computational Fluid Dynamics (CFD). The model makes detailed predictions of the induct spatial distribution and residence time of sorbent, as well as predictions of mercury capture efficiency for particular sorbent flow rates and injection grid configurations. Hence, CFD enables cost efficient optimization of sorbent injection systems for mercury control to a degree that would otherwise be impractical both for new and existing plants. In this way, modeling tools may directly address the main cost component of operating an ACI system – the sorbent expense. A typical 300 MW system is expected to require between $1 and $2 million of sorbent per year, and so even modest reductions (say 10-20%) in necessary sorbent feed injection rates will quickly make any optimization effort very worthwhile. There are few existing models of mercury capture, and these typically make gross assumptions of plug gas flow, zero velocity slip between particle and gas phase, and uniform sorbent dispersion. All of these assumptions are overcome with the current model, which is based on first principles and includes mass transfer processes occurring at multiple scales, ranging from the large-scale transport in the duct to transport within the porous structure of a sorbent particle. In principle any single one of these processes could limit the overall capture of mercury. For example, capture may be severely limited in situations where the dispersion of sorbent is poor, or where adsorption rates are low because of relatively high temperatures. Application examples taken from the DOE/NETL field test program were considered. The sites considered include Brayton Point, Meramec, Monroe, and Yates. Some general lessons learned concerning the impact of turbulence and flow stratification on dispersion and capture will be presented.
Multiphase flow in the advanced fluid dynamics model
Bohl, W.R.; Wilhelm, D.; Berthier, J.; Parker, F.P.; Ichikawa, S.; Goutagny, L.; Ninokata, H.
1988-01-01T23:59:59.000Z
This paper describes the modeling used in the Advanced Fluid Dynamics Model (AFDM), a computer code to investigate new approaches to simulating severe accidents in fast reactors. The AFDM code has 12 topologies describing what material contacts are possible depending on the presence or absence of a given material in a computational cell, the dominant liquid, and the continuous phase. Single-phase, bubbly, churn-turbulent, cellular, and dispersed flow are permitted for the pool situations modeled. Interfacial areas between the continuous and discontinuous phases are convected to allow some tracking of phenomenological histories. Interfacial areas also are modified by models of nucleation, dynamic forces, turbulence, flashing, coalescence, and mass transfer. Heat transfer generally is treated using engineering correlations. Liquid/vapor phase transitions are handled with a nonequililbrium heat-transfer-limited model, whereas melting and freezing processes are based on equilibrium considerations. The Los Alamos SESAME equation of state (EOS) has been inplemented using densities and temperatures as the independent variables. A summary description of the AFDM numerical algorithm is provided. The AFDM code currently is being debugged and checked out. Two sample three-field calculations also are presented. The first is a three-phase bubble column mixing experiment performed at Argonne National Laboratory; the second is a liquid-liquid mixing experiment performed at Kernforschungszentrum, Karlsruhe, that resulted in rapid vapor production. We conclude that only qualitative comparisons currently are possible for complex multiphase situations. Many further model developments can be pursued, but there are limits because of the lack of a comprehensive theory, the lack of detailed multicomponent experimental data, and the difficulties in keeping the resulting model complexities tractable.
Standard Problems for CFD Validation for NGNP - Status Report
Richard W. Johnson; Richard R. Schultz
2010-08-01T23:59:59.000Z
The U.S. Department of Energy (DOE) is conducting research and development to support the resurgence of nuclear power in the United States for both electrical power generation and production of process heat required for industrial processes such as the manufacture of hydrogen for use as a fuel in automobiles. The project is called the Next Generation Nuclear Plant (NGNP) Project, which is based on a Generation IV reactor concept called the very high temperature reactor (VHTR). The VHTR will be of the prismatic or pebble bed type; the former is considered herein. The VHTR will use helium as the coolant at temperatures ranging from 250°C to perhaps 1000°C. While computational fluid dynamics (CFD) has not previously been used for the safety analysis of nuclear reactors in the United States, it is being considered for existing and future reactors. It is fully recognized that CFD simulation codes will have to be validated for flow physics reasonably close to actual fluid dynamic conditions expected in normal operational and accident situations. The “Standard Problem” is an experimental data set that represents an important physical phenomenon or phenomena, whose selection is based on a phenomena identification and ranking table (PIRT) for the reactor in question. It will be necessary to build a database that contains a number of standard problems for use to validate CFD and systems analysis codes for the many physical problems that will need to be analyzed. The first two standard problems that have been developed for CFD validation consider flow in the lower plenum of the VHTR and bypass flow in the prismatic core. Both involve scaled models built from quartz and designed to be installed in the INL’s matched index of refraction (MIR) test facility. The MIR facility employs mineral oil as the working fluid at a constant temperature. At this temperature, the index of refraction of the mineral oil is the same as that of the quartz. This provides an advantage to the optics used for data gathering. Particle image velocimetry (PIV) is used to take the data. The first standard problem represents several flow physics expected to be present in the lower plenum of the prismatic VHTR. In the lower plenum, heated helium coolant in the form of jets issues downward into the plenum and is then forced to turn ninety degrees and flow toward the exit duct. The lower plenum is filled with cylindrical graphite posts that hold up the core. Figure S-1 provides a plan view of the lower plenum. The red circles represent support posts holding up columns of heated blocks. Grey circles represent support posts under columns of reflector blocks. Helium enters the lower plenum at the junctions of the hexagonal blocks.
FLUID DYNAMICAL AND MODELING ISSUES OF CHEMICAL FLOODING FOR ENHANCED OIL RECOVERY
Daripa, Prabir
FLUID DYNAMICAL AND MODELING ISSUES OF CHEMICAL FLOODING FOR ENHANCED OIL RECOVERY Prabir Daripa developed flows in enhanced oil recovery (EOR). In a recent exhaustive study [Transport in Porous Media, 93 fluid flows that occur in porous media during tertiary dis- placement process of chemical enhanced oil
DRILL-STRING NONLINEAR DYNAMICS ACCOUNTING FOR DRILLING FLUID T. G. Ritto
Boyer, Edmond
;1. INTRODUCTION A drill-string is a slender structure used in oil wells to penetrate the soil in search of oilDRILL-STRING NONLINEAR DYNAMICS ACCOUNTING FOR DRILLING FLUID T. G. Ritto R. Sampaio thiagoritto Descartes, 77454 Marne-la-Vallée, France Abstract. The influence of the drilling fluid (or mud) on the drill
Computational Fluids Dynamics and its Application to Multiphase Flows (3 credits)
Chen, Zheng
Computational Fluids Dynamics and its Application to Multiphase Flows (3 credits) Instructor Eric CLIMENT, Dept. of Fluids Mechanics, INP-ENSEEIHT / IMFT (eric.climent@imft.fr) Synopsis Multiphase flows will be introduced, together with their applications to multiphase flows (dispersion, two-way coupling, modelling
AN INVESTIGATION OF THE FLUID DYNAMICS ASPECTS OF THIN LIQUID FILM PROTECTION
California at San Diego, University of
AN INVESTIGATION OF THE FLUID DYNAMICS ASPECTS OF THIN LIQUID FILM PROTECTION SCHEMES FOR INERTIAL Accepted for Publication October 7, 2003 Experimental and numerical studies of the fluid dy- namics of thin- ploding fuel pellets consists of energetic neutrons, pho- tons, and charged particles that eventually
Vortex in a relativistic perfect isentropic fluid and Nambu Goto dynamics
B. Boisseau
1999-11-26T23:59:59.000Z
By a weak deformation of the cylindrical symmetry of the potential vortex in a relativistic perfect isentropic fluid, we study the possible dynamics of the central line of this vortex. In "stiff" material the Nanbu-Goto equations are obtained
Fairman, Randall S. (Randall Scott), 1967-
2002-01-01T23:59:59.000Z
An analysis of current computational fluid dynamics capabilities in predicting mean lift forces for two dimensional foils is conducted. It is shown that both integral boundary layer theory and Reynolds Averaged Navier ...
CFD modeling of commercial-scale entrained-flow coal gasifiers
Ma, J.; Zitney, S.
2012-01-01T23:59:59.000Z
Optimization of an advanced coal-fired integrated gasification combined cycle system requires an accurate numerical prediction of gasifier performance. Computational fluid dynamics (CFD) has been used to model the turbulent multiphase reacting flow inside commercial-scale entrained-flow coal gasifiers. Due to the complexity of the physical and chemical processes involved, the accuracy of sub-models requires further improvement. Built upon a previously developed CFD model for entrained-flow gasification, the advanced physical and chemical sub-models presented in this paper include a moisture vaporization model with consideration of high mass transfer rate and a coal devolatilization model with more species to represent coal volatiles and the heating rate effect on volatile yield. The global gas phase reaction kinetics is also carefully selected. To predict a reasonable peak temperature of the coal/O{sub 2} flame inside an entrained-flow gasifier, the reserve reaction of H{sub 2} oxidation is included in the gas phase reaction model. The enhanced CFD model is applied to simulate two typical commercial-scale oxygen-blown entrained-flow configurations including a single-stage down-fired gasifier and a two-stage up-fired gasifier. The CFD results are reasonable in terms of predicted carbon conversion, syngas exit temperature, and syngas exit composition. The predicted profiles of velocity, temperature, and species mole fractions inside the entrained-flow gasifier models show trends similar to those observed in a diffusion-type flame. The predicted distributions of mole fractions of major species inside both gasifiers can be explained by the heterogeneous combustion and gasification reactions and the homogeneous gas phase reactions. It was also found that the syngas compositions at the CFD model exits are not in chemical equilibrium, indicating the kinetics for both heterogeneous and gas phase homogeneous reactions are important. Overall, the results achieved here indicate that the gasifier models reported in this paper are reliable and accurate enough to be incorporated into process/CFD co-simulations of IGCC power plants for system-wide design and optimization.
Dynamics of end to end loop formation for an isolated chain in viscoelastic fluid
Rajarshi Chakrabarti
2012-04-04T23:59:59.000Z
We theoretically investigate the looping dynamics of a linear polymer immersed in a viscoelastic fluid. The dynamics of the chain is governed by a Rouse model with a fractional memory kernel recently proposed by Weber et al. (S. C. Weber, J. A. Theriot, and A. J. Spakowitz, Phys. Rev. E 82, 011913 (2010)). Using the Wilemski-Fixman (G. Wilemski and M. Fixman, J. Chem. Phys. 60, 866 (1974)) formalism we calculate the looping time for a chain in a viscoelastic fluid where the mean square displacement of the center of mass of the chain scales as t^(1/2). We observe that the looping time is faster for the chain in viscoelastic fluid than for a Rouse chain in Newtonian fluid up to a chain length and above this chain length the trend is reversed. Also no scaling of the looping time with the length of the chain seems to exist for the chain in viscoelastic fluid.
Nonlinear dynamics of three dimensional fluid flow separation
Surana, Amit
2007-01-01T23:59:59.000Z
Flow separation (the detachment of fluid from a no-slip boundary) is a major cause of performance loss in engineering devices, including diffusers, airfoils and jet engines. The systematic study of flow separation dates ...
Adaptive Multiscale Molecular Dynamics of Macromolecular Fluids Steven O. Nielsen,1
Nielsen, Steven O.
diffusion in polymer electrolytes, signal transduction be- tween proteins, nanostructure formationAdaptive Multiscale Molecular Dynamics of Macromolecular Fluids Steven O. Nielsen,1 Preston B 2010; published 3 December 2010) Until now, adaptive atomisticcoarse-grain (A/CG) molecular dynamics
Experimental investigation and CFD analysis on cross flow in the core of PMR200
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Lee, Jeong -Hun; Yoon, Su -Jong; Cho, Hyoung -Kyu; Jae, Moosung; Park, Goon -Cherl
2015-09-01T23:59:59.000Z
The Prismatic Modular Reactor (PMR) is one of the major Very High Temperature Reactor (VHTR) concepts, which consists of hexagonal prismatic fuel blocks and reflector blocks made of nuclear gradegraphite. However, the shape of the graphite blocks could be easily changed by neutron damage duringthe reactor operation and the shape change can create gaps between the blocks inducing the bypass flow.In the VHTR core, two types of gaps, a vertical gap and a horizontal gap which are called bypass gap and cross gap, respectively, can be formed. The cross gap complicates the flow field in the reactor core by connectingmore »the coolant channel to the bypass gap and it could lead to a loss of effective coolant flow in the fuel blocks. Thus, a cross flow experimental facility was constructed to investigate the cross flow phenomena in the core of the VHTR and a series of experiments were carried out under varying flow rates and gap sizes. The results of the experiments were compared with CFD (Computational Fluid Dynamics) analysis results in order to verify its prediction capability for the cross flow phenomena. Fairly good agreement was seen between experimental results and CFD predictions and the local characteristics of the cross flow was discussed in detail. Based on the calculation results, pressure loss coefficient across the cross gap was evaluated, which is necessary for the thermo-fluid analysis of the VHTR core using a lumped parameter code.« less
Rodriguez Prieto, G.; Piriz, A. R.; Lopez Cela, J. J. [E.T.S.I. Industriales and Instituto de Investigaciones Energeticas (INEI), Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Tahir, N. A. [GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt (Germany)
2013-01-15T23:59:59.000Z
A previous theory on dynamic stabilization of Rayleigh-Taylor instability at interfaces between Newtonian fluids is reformulated in order to make evident the analogy of this problem with the related one on dynamic stabilization of ablation fronts in the framework of inertial confinement fusion. Explicit analytical expressions are obtained for the boundaries of the dynamically stable region which turns out to be completely analogue to the stability charts obtained for the case of ablation fronts. These results allow proposing experiments with Newtonian fluids as surrogates for studying the case of ablation fronts. Experiments with Newtonian fluids are presented which demonstrate the validity of the theoretical approach and encourage to pursue experimental research on ablation fronts to settle the feasibility of dynamic stabilization in the inertial confinement fusion scenario.
D)TT(^!rf5\\\\ "bKtSOOO&i. Ris-R-793(EN) Optics and Fluid Dynamics
D)TT(^!rf5\\\\ "bKtSOOO&i. Risø-R-793(EN) Optics and Fluid Dynamics Department Annual Progress Report, Denmark January 1995 #12;Optics and Fluid Dynamics Department Annual Progress Report for 1994 Edited by S;Abstract Research in the Optics and Fiuid Dynamics Department is performed within the following two
Dynamics of filaments and membranes in a viscous fluid
Thomas R. Powers
2009-12-08T23:59:59.000Z
Motivated by the motion of biopolymers and membranes in solution, this article presents a formulation of the equations of motion for curves and surfaces in a viscous fluid. We focus on geometrical aspects and simple variational methods for calculating internal stresses and forces, and we derive the full nonlinear equations of motion. In the case of membranes, we pay particular attention to the formulation of the equations of hydrodynamics on a curved, deforming surface. The formalism is illustrated by two simple case studies: (1) the twirling instability of straight elastic rod rotating in a viscous fluid, and (2) the pearling and buckling instabilities of a tubular liposome or polymersome.
Parcel EulerianLagrangian fluid dynamics of rotating geophysical flows
Oliver, Marcel
, Gottwald, and Reich (2002) and Frank and Reich (2003, 2004) introduced a Hamiltonian Particle Mesh (HPM integra- tion scheme is used. The HPM method is a parcel EulerianLagrangian method: the fluid particles on the advection time scale. The conservation of mass and circulation in the HPM numerical model is shown
Numerical implication of Riemann problem theory for fluid dynamics
Menikoff, R.
1988-01-01T23:59:59.000Z
The Riemann problem plays an important role in understanding the wave structure of fluid flow. It is also crucial step in some numerical algorithms for accurately and efficiently computing fluid flow; Godunov method, random choice method, and from tracking method. The standard wave structure consists of shock and rarefaction waves. Due to physical effects such as phase transitions, which often are indistinguishable from numerical errors in an equation of state, anomalkous waves may occur, ''rarefaction shocks'', split waves, and composites. The anomalous waves may appear in numerical calculations as waves smeared out by either too much artificial viscosity or insufficient resolution. In addition, the equation of state may lead to instabilities of fluid flow. Since these anomalous effects due to the equation of state occur for the continuum equations, they can be expected to occur for all computational algorithms. The equation of state may be characterized by three dimensionless variables: the adiabatic exponent ..gamma.., the Grueneisen coefficient GAMMA, and the fundamental derivative G. The fluid flow anomalies occur when inequalities relating these variables are violated. 18 refs.
Chen, Qingyan "Yan"
BUILDING ENERGY AND CFD SIMULATION Zhiqiang Zhai* Department of Civil, Environmental and Architectural, IN 47907-2088, USA ABSTRACT The integration of building Energy Simulation (ES) and Computational Fluid, Energy Simulation, CFD, Coupling INTRODUCTION A building energy simulation (ES) program predicts building
No-Go Theorems Face Fluid-Dynamical Theories for Quantum Mechanics
Louis Vervoort
2014-06-16T23:59:59.000Z
Recent experiments on fluid-dynamical systems have revealed a series of striking quantum-like features of these macroscopic systems, thus reviving the quest to describe quantum mechanics by classical, in particular fluid-dynamical, theories. However, it is generally admitted that such an endeavor is impossible, on the basis of the 'no-go' theorems of Bell and Kochen-Specker. Here we show that such theorems are inoperative for fluid-dynamical models, even if these are local. Such models appear to violate one of the premises of both theorems, and can reproduce the quantum correlation of the Bell experiment. Therefore the statement that 'local hidden-variable theories are impossible' appears to be untenable for theories just slightly more general than originally envisaged by Bell. We also discuss experimental implications.
Application of computational fluid dynamics to aerosol sampling and concentration
Hu, Shishan
2009-05-15T23:59:59.000Z
Farland Yassin A. Hassan Committee Members, Hamn-Ching Chen John S. Haglund Head of Department, Dennis O?Neal May 2007 Major Subject: Mechanical Engineering iii ABSTRACT Application of Computational Fluid... generous support for my Ph.D. study and his systematic and insightful guidance of my research; ? My committee co-chair, Dr. Yassin A. Hassan, and members Dr. Hamn-Ching Chen, and Dr. John S. Haglund for their technical support; ? Mr. Carlos A. Ortiz...
Dalziel, Stuart
flow from a volcanic eruption? What is the effect of wind conditions on buoyancy driven ventilation in a building, and how can we use this to our advantage? Can we control the hydrodynamic instabilities of a suspended second phase? Is mix- ing sensitive to how we put the energy into the system? How do fluids
Frey, Pascal
2009-01-01T23:59:59.000Z
be encountered as a function of the Ohnesorge number. For large values, a laminar flow is encountered insideIOP PUBLISHING FLUID DYNAMICS RESEARCH Fluid Dyn. Res. 41 (2009) 065001 (24pp) doi:10 Abstract This work presents current advances in the numerical simulation of two- phase flows using a volume
R. James Kirkpatrick; Andrey G. Kalinichev
2008-11-25T23:59:59.000Z
Research supported by this grant focuses on molecular scale understanding of central issues related to the structure and dynamics of geochemically important fluids, fluid-mineral interfaces, and confined fluids using computational modeling and experimental methods. Molecular scale knowledge about fluid structure and dynamics, how these are affected by mineral surfaces and molecular-scale (nano-) confinement, and how water molecules and dissolved species interact with surfaces is essential to understanding the fundamental chemistry of a wide range of low-temperature geochemical processes, including sorption and geochemical transport. Our principal efforts are devoted to continued development of relevant computational approaches, application of these approaches to important geochemical questions, relevant NMR and other experimental studies, and application of computational modeling methods to understanding the experimental results. The combination of computational modeling and experimental approaches is proving highly effective in addressing otherwise intractable problems. In 2006-2007 we have significantly advanced in new, highly promising research directions along with completion of on-going projects and final publication of work completed in previous years. New computational directions are focusing on modeling proton exchange reactions in aqueous solutions using ab initio molecular dynamics (AIMD), metadynamics (MTD), and empirical valence bond (EVB) approaches. Proton exchange is critical to understanding the structure, dynamics, and reactivity at mineral-water interfaces and for oxy-ions in solution, but has traditionally been difficult to model with molecular dynamics (MD). Our ultimate objective is to develop this capability, because MD is much less computationally demanding than quantum-chemical approaches. We have also extended our previous MD simulations of metal binding to natural organic matter (NOM) to a much longer time scale (up to 10 ns) for significantly larger systems. These calculations have allowed us, for the first time, to study the effects of metal cations with different charges and charge density on the NOM aggregation in aqueous solutions. Other computational work has looked at the longer-time-scale dynamical behavior of aqueous species at mineral-water interfaces investigated simultaneously by NMR spectroscopy. Our experimental NMR studies have focused on understanding the structure and dynamics of water and dissolved species at mineral-water interfaces and in two-dimensional nano-confinement within clay interlayers. Combined NMR and MD study of H2O, Na+, and Cl- interactions with the surface of quartz has direct implications regarding interpretation of sum frequency vibrational spectroscopic experiments for this phase and will be an important reference for future studies. We also used NMR to examine the behavior of K+ and H2O in the interlayer and at the surfaces of the clay minerals hectorite and illite-rich illite-smectite. This the first time K+ dynamics has been characterized spectroscopically in geochemical systems. Preliminary experiments were also performed to evaluate the potential of 75As NMR as a probe of arsenic geochemical behavior. The 75As NMR study used advanced signal enhancement methods, introduced a new data acquisition approach to minimize the time investment in ultra-wide-line NMR experiments, and provides the first evidence of a strong relationship between the chemical shift and structural parameters for this experimentally challenging nucleus. We have also initiated a series of inelastic and quasi-elastic neutron scattering measurements of water dynamics in the interlayers of clays and layered double hydroxides. The objective of these experiments is to probe the correlations of water molecular motions in confined spaces over the scale of times and distances most directly comparable to our MD simulations and on a time scale different than that probed by NMR. This work is being done in collaboration with Drs. C.-K. Loong, N. de Souza, and A.I. Kolesnikov at the Intense Pulsed
Multi-Particle Collision Dynamics Algorithm for Nematic Fluids
Tyler N. Shendruk; Julia M. Yeomans
2015-04-18T23:59:59.000Z
Research on transport, self-assembly and defect dynamics within confined, flowing liquid crystals requires versatile and computationally efficient mesoscopic algorithms to account for fluctuating nematohydrodynamic interactions. We present a multi-particle collision dynamics (MPCD) based algorithm to simulate liquid-crystal hydrodynamic and director fields in two and three dimensions. The nematic-MPCD method is shown to successfully reproduce the features of a nematic liquid crystal, including a nematic-isotropic phase transition with hysteresis in 3D, defect dynamics, isotropic Frank elastic coefficients, tumbling and shear alignment regimes and boundary condition dependent order parameter fields.
2.13 HEAT TRANSFER & FLUID FLOW IN MICROCHANNELS 2.13.7-1 Molecular dynamics methods in
Maruyama, Shigeo
2.13 HEAT TRANSFER & FLUID FLOW IN MICROCHANNELS 2.13.7-1 2.13.7 Molecular dynamics methods in microscale heat transfer Shigeo Maruyama A. Introduction In normal heat transfer and fluid flow calculations of molecules. This situation is approached in microscale heat transfer and fluid flow. Molecular level
Parcel EulerianLagrangian fluid dynamics of rotating geophysical flows
Al Hanbali, Ahmad
of dynamics used in Hamiltonian particle mesh method (HPM) of Frank and Reich (2003, 2004): dX dt = U Hs = U;' & $ % · HPM: potential energy calculated on Eulerian mesh; Lagrangian evolution particles. · ODE's per parcel
Anomalous dynamics of an elastic membrane in an active fluid
S. A. Mallory; C. Valeriani; A. Cacciuto
2015-05-06T23:59:59.000Z
Using numerical simulations, we characterized the behavior of an elastic membrane immersed in an active fluid. Our findings reveal a nontrivial folding and re-expansion of the membrane that is controlled by the interplay of its resistance to bending and the self-propulsion strength of the active components in solution. We show how flexible membranes tend to collapse into multi-folded states, whereas stiff membranes oscillates between an extended configuration and a singly folded state. This study provides a simple example of how to exploit the random motion of active particles to perform mechanical work at the micro-scale.
Advanced CFD Models for High Efficiency Compression Ignition...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
CFD Models for High Efficiency Compression Ignition Engines Advanced CFD Models for High Efficiency Compression Ignition Engines Advanced CFD models for high efficiency...
Progress in Computational Fluid Dynamics, Volume 2, Nos. 2/3/4, 2002144 A numerical investigation of
Zhao, Tianshou
Progress in Computational Fluid Dynamics, Volume 2, Nos. 2/3/4, 2002144 A numerical investigation.16 mm, under both cooling and heating conditions, with and without gravity, were obtained. It is shown', Progress in Computational fluid Dynamics, Vol. 2, Nos. 2/3/4, pp. 144152. NOMENCLATURE A tube cross
Collective dynamics of molecular motors pulling on fluid membranes
O. Campas; Y. Kafri; K. B. Zeldovich; J. Casademunt; J. -F. Joanny
2005-12-08T23:59:59.000Z
The collective dynamics of $N$ weakly coupled processive molecular motors are considered theoretically. We show, using a discrete lattice model, that the velocity-force curves strongly depend on the effective dynamic interactions between motors and differ significantly from a simple mean field prediction. They become essentially independent of $N$ if it is large enough. For strongly biased motors such as kinesin this occurs if $N\\gtrsim 5$. The study of a two-state model shows that the existence of internal states can induce effective interactions.
Dynamics of a confined dusty fluid in a sheared ion flow
Laishram, Modhuchandra; Sharma, Devendra; Kaw, Predhiman K. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)
2014-07-15T23:59:59.000Z
Dynamics of an isothermally driven dust fluid is analyzed which is confined in an azimuthally symmetric cylindrical setup by an effective potential and is in equilibrium with an unconfined sheared flow of a streaming plasma. Cases are analyzed where the confining potential constitutes a barrier for the driven fluid, limiting its spatial extension and boundary velocity. The boundary effects entering the formulation are characterized by applying the appropriate boundary conditions and a range of solutions exhibiting single and multiple vortex are obtained. The equilibrium solutions considered in the cylindrical setup feature a transition from single to multiple vortex state of the driven flow. Effects of (i) the variation in dust viscosity, (ii) coupling between the driving and the driven fluid, and (iii) a friction determining the equilibrium dynamics of the driven system are characterized.
Tezduyar, Tayfun E.
Chapter 17 in Encyclopedia of Computational Mechanics, Volume 3: Fluids Finite Element Methods surfaces, two-fluid interfaces, fluidobject and fluidstructure in- teractions, and moving mechanical in Encyclopedia of Computational Mechanics, Volume 3: Fluids (eds. E. Stein, R. De Borst and T.J.R. Hughes), John
T. S. Biro; E. Molnar
2012-01-28T23:59:59.000Z
We derive equations for fluid dynamics from a non-extensive Boltzmann transport equation consistent with Tsallis' non-extensive entropy formula. We evaluate transport coefficients employing the relaxation time approximation and investigate non-extensive effects in leading order dissipative phenomena at relativistic energies, like heat conductivity, shear and bulk viscosity.
Under consideration for publication in J. Fluid Mech. 1 Nonlinear dynamics over rough topography
Vanneste, Jacques
Under consideration for publication in J. Fluid Mech. 1 Nonlinear dynamics over rough topography-dimensional, pe- riodic or random, small-scale topography is investigated using an asymptotic approach. Averaged (or homogenised) evolution equations which account for the flow-topography in- teraction are derived
Fluid Dynamics Dr. A.J. Hogg Example Sheet 5 November 2001
Hogg, Andrew
leads smoothly into a horizontal tube of uniform cross-section and length L. The diameter of this tubeFluid Dynamics Dr. A.J. Hogg Example Sheet 5 November 2001 Irrotational Flows 1. An irrotational flow is given by the velocity potential (x) where (x) = -m 4(x2 + y2 + z2)1/2 . Find the velocity field
Simulating Buoyancy-Driven Airflow in Buildings by1 Coarse-Grid Fast Fluid Dynamics2
Chen, Qingyan "Yan"
1 Simulating Buoyancy-Driven Airflow in Buildings by1 Coarse-Grid Fast Fluid Dynamics2 Mingang Jin1. Introduction33 Whole-building airflow simulations are required in applications such as natural ventilation34 design, coupled building airflow and energy simulation, smoke control, and air quality diagnosis35
Molecular to fluid dynamics: The consequences of stochastic molecular motion Stefan Heinz*
Heinz, Stefan
to derive a hierarchy of algebraic expressions for the molecular stress tensor and heat flux. A scaling of ordinary irreversible thermodynamics [3]) transport equations for the molecular stress tensor and heat flux equations. The stochastic model is used to derive fluid dynamic equations where the molecular stress tensor
Computational Fluid Dynamics Modeling of a Lithium/Thionyl Chloride Battery with Electrolyte Flow
Wang, Chao-Yang
Computational Fluid Dynamics Modeling of a Lithium/Thionyl Chloride Battery with Electrolyte Flow W-dimensional model is developed to simulate discharge of a primary lithium/thionyl chloride battery. The model to the first task with important examples of lead-acid,1-3 nickel-metal hydride,4-8 and lithium-based batteries
A next-generation modeling capability assesses wind turbine array fluid dynamics and aeroelastic simulations Characterizing and optimizing overall performance of wind plants composed of large numbers at the National Renewable Energy Laboratory (NREL) are coupling physical models of the atmosphere and wind
International Journal of Computational Fluid Dynamics Vol. 00, No. 00, February 2010, 143
Paris-Sud XI, Université de
pressure q total heat flux qref energy of fluid at a given reference state ReL Reynolds number based in the performance: reduced flow rates, lower pressure increases in pumps, load asymmetry, vibrations, noise and erosion. In most industrial applications, cavitating flows are turbulent and the dynamics of the formed
SOLAR SUB-SURFACE FLUID DYNAMICS DESCRIPTORS DERIVED FROM GONG AND MDI DATA
Corbard, Thierry
SOLAR SUB-SURFACE FLUID DYNAMICS DESCRIPTORS DERIVED FROM GONG AND MDI DATA R. Komm National Solar Observatory 950 N. Cherry Ave., Tucson, AZ 85719 komm@noao.edu ABSTRACT We analyze GONG and MDI observations closer to the surface. GONG and MDI data show the same results. Di#11;erences occur mainly at high
Geophysical and Astrophysical Fluid Dynamics, Vol. 101, Nos. 56, OctoberDecember 2007, 469487
Lathrop, Daniel P.
Geophysical and Astrophysical Fluid Dynamics, Vol. 101, Nos. 56, OctoberDecember 2007, 469, USA zInstitute of Geophysics, University of Go¨ ttingen, Friedrich-Hund-Platz 1, D-37077 Go¨ ttingen (though later work by Banka and *Corresponding author. Email: dpl@complex.umd.edu Geophysical
Fluxion: An Innovative Fluid Dynamics Game on Multi-Touch Handheld Device
Boyer, Edmond
)). For example, players can place a heater to turn water into gas or place a freezer to turn it into ice. hal) (b) (c) Fig. 3. (a) A heater turns water into gas. (b) Water is turned into an ice cube so simulation on iPhone to create an innovative game experience. Using fluid dynamics and water tri
Transport coefficients of a mesoscopic fluid dynamics model
N. Kikuchi; C. M. Pooley; J. F. Ryder; J. M. Yeomans
2003-02-21T23:59:59.000Z
We investigate the properties of stochastic rotation dynamics (Malevanets-Kapral method), a mesoscopic model used for simulating fluctuating hydrodynamics. Analytical results are given for the transport coefficients. We discuss the most efficient way of measuring the transport properties and obtain excellent agreement between the theoretical and numerical calculations.
PETER LEE OLSON Present Position: Professor of Geophysical Fluid Dynamics
Olson, Peter L.
Union, Tectonophysics Section Scientific Advisory Board, Maryland Power Plant Siting Program Scientific Dynamics EDUCATION: Ph.D. Geophysics, June 1977, University of California, Berkeley, California M.A. Geophysics, June 1974, University of California, Berkeley, California B.A. Geology, June 1972, University
Coupled full core neutron transport/CFD simulations of pressurized water reactors
Kochunas, B.; Stimpson, S.; Collins, B.; Downar, T. [Dept. of Nuclear Engineering and Radiological Sciences, Univ. of Michigan, 2200 Bonisteel Blvd, Ann Arbor, MI 48104 (United States); Brewster, R.; Baglietto, E. [CD-adapco, 60 Broadhollow Road, Melville, NY 11747 (United States); Yan, J. [Westinghouse Electric Company LLC, Columbia, SC (United States)
2012-07-01T23:59:59.000Z
Recently as part of the CASL project, a capability to perform 3D whole-core coupled neutron transport and computational fluid dynamics (CFD) calculations was demonstrated. This work uses the 2D/1D transport code DeCART and the commercial CFD code STAR-CCM+. It builds on previous CASL work demonstrating coupling for smaller spatial domains. The coupling methodology is described along with the problem simulated and results are presented for fresh hot full power conditions. An additional comparison is made to an equivalent model that uses lower order T/H feedback to assess the importance and cost of high fidelity feedback to the neutronics problem. A simulation of a quarter core Combustion Engineering (CE) PWR core was performed with the coupled codes using a Fixed Point Gauss-Seidel iteration technique. The total approximate calculation requirements are nearly 10,000 CPU hours and 1 TB of memory. The problem took 6 coupled iterations to converge. The CFD coupled model and low order T/H feedback model compared well for global solution parameters, with a difference in the critical boron concentration and average outlet temperature of 14 ppm B and 0.94 deg. C, respectively. Differences in the power distribution were more significant with maximum relative differences in the core-wide pin peaking factor (Fq) of 5.37% and average relative differences in flat flux region power of 11.54%. Future work will focus on analyzing problems more relevant to CASL using models with less approximations. (authors)
PIV Uncertainty Methodologies for CFD Code Validation at the MIR Facility
Piyush Sabharwall; Richard Skifton; Carl Stoots; Eung Soo Kim; Thomas Conder
2013-12-01T23:59:59.000Z
Currently, computational fluid dynamics (CFD) is widely used in the nuclear thermal hydraulics field for design and safety analyses. To validate CFD codes, high quality multi dimensional flow field data are essential. The Matched Index of Refraction (MIR) Flow Facility at Idaho National Laboratory has a unique capability to contribute to the development of validated CFD codes through the use of Particle Image Velocimetry (PIV). The significance of the MIR facility is that it permits non intrusive velocity measurement techniques, such as PIV, through complex models without requiring probes and other instrumentation that disturb the flow. At the heart of any PIV calculation is the cross-correlation, which is used to estimate the displacement of particles in some small part of the image over the time span between two images. This image displacement is indicated by the location of the largest peak. In the MIR facility, uncertainty quantification is a challenging task due to the use of optical measurement techniques. Currently, this study is developing a reliable method to analyze uncertainty and sensitivity of the measured data and develop a computer code to automatically analyze the uncertainty/sensitivity of the measured data. The main objective of this study is to develop a well established uncertainty quantification method for the MIR Flow Facility, which consists of many complicated uncertainty factors. In this study, the uncertainty sources are resolved in depth by categorizing them into uncertainties from the MIR flow loop and PIV system (including particle motion, image distortion, and data processing). Then, each uncertainty source is mathematically modeled or adequately defined. Finally, this study will provide a method and procedure to quantify the experimental uncertainty in the MIR Flow Facility with sample test results.
GTRF Calculations Using Hydra-TH (L3 Milestone THM.CFD.P5.05)
Bakosi, Jozsef [Los Alamos National Laboratory; Christon, Mark A. [Los Alamos National Laboratory; Francois, Marianne M. [Los Alamos National Laboratory; Lowrie, Robert B. [Los Alamos National Laboratory; Nourgaliev, Robert [Los Alamos National Laboratory
2012-09-05T23:59:59.000Z
This report describes the work carried out for completion of the Thermal Hydraulics Methods (THM) Level 3 Milestone THM.CFD.P5.05 for the Consortium for Advanced Simulation of Light Water Reactors (CASL). A series of body-fitted computational meshes have been generated by Numeca's Hexpress/Hybrid, a.k.a. 'Spider', meshing technology for the V5H 3 x 3 and 5 x 5 rod bundle geometries and subsequently used to compute the fluid dynamics of grid-to-rod fretting (GTRF). Spider is easy to use, fast, and automatically generates high-quality meshes for extremely complex geometries, required for the GTRF problem. Hydra-TH has been used to carry out large-eddy simulations on both 3 x 3 and 5 x 5 geometries, using different mesh resolutions. The results analyzed show good agreement with Star-CCM+ simulations and experimental data.
Simultaneous CFD evaluation of wind flow and dust emission in open storage piles
Diego, I.; Pelegry, A.; Torno, S.; Torano, J.; Menendez, M. [University of Oviedo, Asturias (Spain). School of Mines
2009-07-15T23:59:59.000Z
Dust emission from storage yards is a multivariable problem to be solved not only at any new installation in order to obtain the licenses from the involved authorities but also at existing yards to continue the operation. Engineers have a great variety of methodologies available at the market to estimate such emissions, but in general the process is divided into two independent stages: wind flow analysis and application of emission rates into such wind pattern. This paper summarizes the research developed by this group to link both steps: by using CFX version 10.0, a powerful computational fluid dynamics (CFD) software, the wind flow around the piles is predicted, or even through a complex yard, and at the same time by implementing new subroutines introduced into the standard software, the program is able to give a quantitative evaluation of the total fugitive dust.
Global dynamics and asymptotics for monomial scalar field potentials and perfect fluids
Alho, Artur; Uggla, Claes
2015-01-01T23:59:59.000Z
We consider a minimally coupled scalar field with a monomial potential and a perfect fluid in flat FLRW cosmology. We apply local and global dynamical systems techniques to a new three-dimensional dynamical systems reformulation of the field equations on a compact state space. This leads to a visual global description of the solution space and asymptotic behavior. At late times we employ averaging techniques to prove statements about how the relationship between the equation of state of the fluid and the monomial exponent of the scalar field affects asymptotic source dominance and asymptotic manifest self-similarity breaking. We also situate the `attractor' solution in the three-dimensional state space and show that it corresponds to the one-dimensional unstable center manifold of a de Sitter fixed point, located on an unphysical boundary associated with the dynamics at early times. By deriving a center manifold expansion we obtain approximate expressions for the attractor solution. We subsequently improve th...
Grant Hawkes; James O'Brien
2012-06-01T23:59:59.000Z
Various three dimensional computational fluid dynamics (CFD) models of solid oxide electrolyzers have been created and analyzed at the Idaho National Laboratory since the inception of the Nuclear Hydrogen Initiative in 2004. Three models presented herein include: a 60 cell planar cross flow with inlet and outlet plenums, 10 cell integrated planar cross flow, and internally manifolded five cell planar cross flow. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) module adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, activation over-potential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Contour plots of local electrolyte temperature, current density, and Nernst potential indicated the effects of heat transfer, endothermic reaction, Ohmic heating, and change in local gas composition. Results are discussed for using these models in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production is reported herein. Contour plots and discussion show areas of likely cell degradation, flow distribution in inlet plenum, and flow distribution across and along the flow channels of the current collectors
Dynamic mesoscale model of dipolar fluids via fluctuating hydrodynamics
Persson, Rasmus A. X.; Chu, Jhih-Wei, E-mail: jwchu@nctu.edu.tw [Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu 30068, Taiwan (China); Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 30068, Taiwan (China); Voulgarakis, Nikolaos K. [Department of Mathematics, Washington State University, Richland, Washington 99372 (United States)
2014-11-07T23:59:59.000Z
Fluctuating hydrodynamics (FHD) is a general framework of mesoscopic modeling and simulation based on conservational laws and constitutive equations of linear and nonlinear responses. However, explicit representation of electrical forces in FHD has yet to appear. In this work, we devised an Ansatz for the dynamics of dipole moment densities that is linked with the Poisson equation of the electrical potential ? in coupling to the other equations of FHD. The resulting ?-FHD equations then serve as a platform for integrating the essential forces, including electrostatics in addition to hydrodynamics, pressure-volume equation of state, surface tension, and solvent-particle interactions that govern the emergent behaviors of molecular systems at an intermediate scale. This unique merit of ?-FHD is illustrated by showing that the water dielectric function and ion hydration free energies in homogeneous and heterogenous systems can be captured accurately via the mesoscopic simulation. Furthermore, we show that the field variables of ?-FHD can be mapped from the trajectory of an all-atom molecular dynamics simulation such that model development and parametrization can be based on the information obtained at a finer-grained scale. With the aforementioned multiscale capabilities and a spatial resolution as high as 5 Å, the ?-FHD equations represent a useful semi-explicit solvent model for the modeling and simulation of complex systems, such as biomolecular machines and nanofluidics.
Azwinndini Muronga
2007-07-31T23:59:59.000Z
In the causal theory of relativistic dissipative fluid dynamics, there are conditions on the equation of state and other thermodynamic properties such as the second-order coefficients of a fluid that need to be satisfied to guarantee that the fluid perturbations propagate causally and obey hyperbolic equations. The second-order coefficients in the causal theory, which are the relaxation times for the dissipative degrees of freedom and coupling constants between different forms of dissipation (relaxation lengths), are presented for partonic and hadronic systems. These coefficients involves relativistic thermodynamic integrals. The integrals are presented for general case and also for different regimes in the temperature--chemical potential plane. It is shown that for a given equation of state these second-order coefficients are not additional parameters but they are determined by the equation of state. We also present the prescription on the calculation of the freeze-out particle spectra from the dynamics of relativistic non-ideal fluids.
Liquid phase fluid dynamic (methanol) run in the LaPorte alternative fuels development unit
Bharat L. Bhatt
1997-05-01T23:59:59.000Z
A fluid dynamic study was successfully completed in a bubble column at DOE's Alternative Fuels Development Unit (AFDU) in LaPorte, Texas. Significant fluid dynamic information was gathered at pilot scale during three weeks of Liquid Phase Methanol (LPMEOJP) operations in June 1995. In addition to the usual nuclear density and temperature measurements, unique differential pressure data were collected using Sandia's high-speed data acquisition system to gain insight on flow regime characteristics and bubble size distribution. Statistical analysis of the fluctuations in the pressure data suggests that the column was being operated in the churn turbulent regime at most of the velocities considered. Dynamic gas disengagement experiments showed a different behavior than seen in low-pressure, cold-flow work. Operation with a superficial gas velocity of 1.2 ft/sec was achieved during this run, with stable fluid dynamics and catalyst performance. Improvements included for catalyst activation in the design of the Clean Coal III LPMEOH{trademark} plant at Kingsport, Tennessee, were also confirmed. In addition, an alternate catalyst was demonstrated for LPMEOH{trademark}.
Gerhard Strydom; Su-Jong Yoon
2014-04-01T23:59:59.000Z
Computational Fluid Dynamics (CFD) evaluation of homogeneous and heterogeneous fuel models was performed as part of the Phase I calculations of the International Atomic Energy Agency (IAEA) Coordinate Research Program (CRP) on High Temperature Reactor (HTR) Uncertainties in Modeling (UAM). This study was focused on the nominal localized stand-alone fuel thermal response, as defined in Ex. I-3 and I-4 of the HTR UAM. The aim of the stand-alone thermal unit-cell simulation is to isolate the effect of material and boundary input uncertainties on a very simplified problem, before propagation of these uncertainties are performed in subsequent coupled neutronics/thermal fluids phases on the benchmark. In many of the previous studies for high temperature gas cooled reactors, the volume-averaged homogeneous mixture model of a single fuel compact has been applied. In the homogeneous model, the Tristructural Isotropic (TRISO) fuel particles in the fuel compact were not modeled directly and an effective thermal conductivity was employed for the thermo-physical properties of the fuel compact. On the contrary, in the heterogeneous model, the uranium carbide (UCO), inner and outer pyrolytic carbon (IPyC/OPyC) and silicon carbide (SiC) layers of the TRISO fuel particles are explicitly modeled. The fuel compact is modeled as a heterogeneous mixture of TRISO fuel kernels embedded in H-451 matrix graphite. In this study, a steady-state and transient CFD simulations were performed with both homogeneous and heterogeneous models to compare the thermal characteristics. The nominal values of the input parameters are used for this CFD analysis. In a future study, the effects of input uncertainties in the material properties and boundary parameters will be investigated and reported.
The Dynamics of a Two-Fluid Bianchi Type I Universe
Ikjyot Singh Kohli; Michael C. Haslam
2015-07-19T23:59:59.000Z
We use a dynamical systems approach based on the method of orthonormal frames to study the dynamics of a two-fluid, non-tilted Bianchi Type I cosmological model. In our model, one of the fluids is a fluid with bulk viscosity, while the other fluid assumes the role of a cosmological constant and represents nonnegative vacuum energy. We begin by completing a detailed fixed-points analysis of the system which gives information about the local sinks, sources and saddles. We then proceeded to analyze the global features of the dynamical system by using topological methods by finding the $\\alpha$- and $\\omega$-limit sets. The fixed points found are a flat FLRW universe, an Einstein-de Sitter universe, a de Sitter universe, a mixed FLRW universe with both vacuum and non-vacuum energy, and a Kasner universe. We then find conditions for which each equilibrium point was a saddle, sink, or source, and attempt to describe the global and past asymptotic behaviour of the model with respect to each fixed point. The flat FLRW universe solution we found with both vacuum and non-vacuum energy is clearly of primary importance with respect to modelling the present-day universe. In particular, we show that this equilibrium point is a local sink and a saddle of the dynamical system, so there are orbits that approach this equilibrium point in the future. Therefore, there exists a time period for which our cosmological model will isotropize and be compatible with present-day observations of a high degree of isotropy of the cosmic microwave background in addition to the existence of both vacuum and non-vacuum energy.
The comparison of the 3-fluid dynamic model with experimental data
Kizka, V A
2015-01-01T23:59:59.000Z
The method of comparison of theoretical predictions with experimental data had been developed.This method allows estimate the quality of theory. Published theoretical data of the three-fluid dynamic (3FD) model applied to the experimental data from heavy-ion collisions at the energy range $\\sqrt{s_{NN}}\\,=\\,2.7 - 63$ GeV were used as example of application of the developed methodology.
The comparison of the 3-fluid dynamic model with experimental data
V. A. Kizka
2015-08-13T23:59:59.000Z
The method of comparison of theoretical predictions with experimental data had been developed.This method allows estimate the quality of theory. Published theoretical data of the three-fluid dynamic (3FD) model applied to the experimental data from heavy-ion collisions at the energy range $\\sqrt{s_{NN}}\\,=\\,2.7 - 63$ GeV were used as example of application of the developed methodology.
Dynamics of a dielectric droplet suspended in a magnetic fluid in electric and magnetic fields
Arthur Zakinyan; Elena Tkacheva; Yury Dikansky
2012-03-24T23:59:59.000Z
The behavior of a microdrop of dielectric liquid suspended in a magnetic fluid and exposed to the action of electric and magnetic fields is studied experimentally. With increasing electric field, the deformation of droplets into oblate ellipsoid, toroid and curved toroid was observed. At the further increase in the electric field, the bursting of droplets was also revealed. The electrorotation of deformed droplets was observed and investigated. The influence of an additional magnetic field on the droplet dynamics was studied. The main features of the droplet dynamics were interpreted and theoretically examined.
Dynamically orthogonal field equations for stochastic fluid flows and particle dynamics
Sapsis, Themistoklis P
2011-01-01T23:59:59.000Z
In the past decades an increasing number of problems in continuum theory have been treated using stochastic dynamical theories. This is because dynamical systems governing real processes always contain some elements ...
J. Non-Newtonian Fluid Mech. 135 (2006) 97108 Impact dynamics of a solid sphere falling into a
2006-01-01T23:59:59.000Z
effects dominate (i.e. the Reynolds number Re 1), then the drag forces will come into balance with gravityJ. Non-Newtonian Fluid Mech. 135 (2006) 97108 Impact dynamics of a solid sphere falling of the impact of a solid sphere on the free surface of a viscoelastic wormlike micellar fluid. Spheres
Approved Module Information for ME4501, 2014/5 Module Title/Name: Computational Fluid Dynamics and
Neirotti, Juan Pablo
and Applications Module Code: ME4501 School: Engineering and Applied Science Module Type: Standard Module New-requisites: Thermodynamics and Fluids (ME3011). Engineering Mathematics 2 (AM21EM). Co-requisites: None Specified ModuleApproved Module Information for ME4501, 2014/5 Module Title/Name: Computational Fluid Dynamics
Price, James F.
This collection of three essays was developed from the author's experience teaching Fluid Dynamics of the Atmosphere and Ocean, 12.800, offered to graduate students entering the MIT/WHOI Joint Program in Oceanography. The ...
Nanoscopic Dynamics of Phospholipid in Unilamellar Vesicles: Effect of Gel to Fluid Phase Transition
Sharma, Veerendra K [ORNL; Mamontov, Eugene [ORNL; Anunciado, Divina B [ORNL; O'Neill, Hugh Michael [ORNL; Urban, Volker S [ORNL
2015-01-01T23:59:59.000Z
Dynamics of phospholipids in unilamellar vesicles (ULV) is of interest in biology, medical, and food sciences since these molecules are widely used as biocompatible agents and a mimic of cell membrane systems. We have investigated the nanoscopic dynamics of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) phospholipid in ULV as a function of temperature using elastic and quasielastic neutron scattering (QENS). The dependence of the signal on the scattering momentum transfer, which is a critical advantage of neutron scattering techniques, allows the detailed analysis of the lipid motions that cannot be carried out by other means. In agreement with a differential scanning calorimetry measurement, a sharp rise in the elastic scattering intensity below ca. 296 K indicates a phase transition from the high-temperature fluid phase to the low-temperature solid gel phase. The microscopic lipid dynamics exhibits qualitative differences between the solid gel phase (in a measurement at 280 K) and the fluid phase (in a measurement at a physiological temperature of 310 K). The data analysis invariably shows the presence of two distinct motions: the whole lipid molecule motion within a monolayer, or lateral diffusion, and the relatively faster internal motion of the DMPC molecule. The lateral diffusion of the whole lipid molecule is found to be Fickian in character, whereas the internal lipid motions are of localized character, consistent with the structure of the vesicles. The lateral motion slows down by an order of magnitude in the solid gel phase, whereas for the internal motion not only the time scale, but also the character of the motion changes upon the phase transition. In the solid gel phase, the lipids are more ordered and undergo uniaxial rotational motion. However, in the fluid phase, the hydrogen atoms of the lipid tails undergo confined translation diffusion rather than uniaxial rotational diffusion. The localized translational diffusion of the hydrogen atoms of the lipid tails is a manifestation of the flexibility of the chains acquired in the fluid phase. Because of this flexibility, both the local diffusivity and the confinement volume for the hydrogen atoms increase linearly from near the lipid s polar head group to the end of its hydrophobic tail. Our results present a quantitative and detailed picture of the effect of the gel-fluid phase transition on the nanoscopic lipid dynamics in ULV. The data analysis approach developed here has a potential for probing the dynamic response of lipids to the presence of additional cell membrane components.
Faybishenko, B. (ed.)
1999-02-01T23:59:59.000Z
This publication contains extended abstracts of papers presented at the International Symposium ''Dynamics of Fluids in Fractured Rocks: Concepts and Recent Advances'' held at Ernest Orlando Lawrence Berkeley National Laboratory on February 10-12, 1999. This Symposium is organized in Honor of the 80th Birthday of Paul A. Witherspoon, who initiated some of the early investigations on flow and transport in fractured rocks at the University of California, Berkeley, and at Lawrence Berkeley National Laboratory. He is a key figure in the development of basic concepts, modeling, and field measurements of fluid flow and contaminant transport in fractured rock systems. The technical problems of assessing fluid flow, radionuclide transport, site characterization, modeling, and performance assessment in fractured rocks remain the most challenging aspects of subsurface flow and transport investigations. An understanding of these important aspects of hydrogeology is needed to assess disposal of nu clear wastes, development of geothermal resources, production of oil and gas resources, and remediation of contaminated sites. These Proceedings of more than 100 papers from 12 countries discuss recent scientific and practical developments and the status of our understanding of fluid flow and radionuclide transport in fractured rocks. The main topics of the papers are: Theoretical studies of fluid flow in fractured rocks; Multi-phase flow and reactive chemical transport in fractured rocks; Fracture/matrix interactions; Hydrogeological and transport testing; Fracture flow models; Vadose zone studies; Isotopic studies of flow in fractured systems; Fractures in geothermal systems; Remediation and colloid transport in fractured systems; and Nuclear waste disposal in fractured rocks.
Study of ebullated bed fluid dynamics. Final progress report, September 1980-July 1983
Schaefer, R.J.; Rundell, D.N.; Shou, J.K.
1983-07-01T23:59:59.000Z
The fluid dynamics occurring in HRI's H-coal process development unit coal liquefaction reactor during Run PDU-10 were measured and compared with Amoco Oil cold-flow fluidization results. It was found that catalyst bed expansions and gas holdups are higher in the PDU than those observed in the cold-flow tests for slurries having the same nominal viscosity. Comparison of PDU results with cold-flow results shows that the bulk of the operating reactor gas flow lies in the ideal bubbly regime. It also appears that the gas bubbles in these PDU tests are rising quite slowly. Only two of the operating points in our test program on the PDU were found to lie in the churn turbulent regime. Existence of churn turbulent behavior during these two experiments is consistent with trends observed in earlier cold-flow experiments. Two- and three-phase fluidization experiments were carried out in Amoco's cold-flow fluid dynamics unit. The data base now includes fluidization results for coal char/kerosene slurry concentrations of 4.0, 9.8, and 20.7 vol% in addition to the 15.5 and 17.8 vol% data from our earlier work. Both HDS-2A and Amocat-1A catalysts were used in the tests. Bed expansion is primarily a function of slurry velocity, with gas velocity having only a weak effect. Bed contractions have been observed in some cases at sufficiently high gas velocity. Gas and liquid holdups were found to be uniform across the cross-section of the Amoco cold-flow fluid dynamics pilot plant. A viscometer was adapted for measurement of the viscosity of coal slurries at high temperature and pressure. Based on experiments carried out in the Amoco cold-flow unit, a significant degree of backmixing was found to occur in the H-Coal system. 70 references, 93 figures, 32 tables.
Hp-spectral Methods for Structural Mechanics and Fluid Dynamics Problems
Ranjan, Rakesh
2011-08-08T23:59:59.000Z
stream_source_info RANJAN-DISSERTATION.pdf.txt stream_content_type text/plain stream_size 315969 Content-Encoding ISO-8859-1 stream_name RANJAN-DISSERTATION.pdf.txt Content-Type text/plain; charset=ISO-8859-1 HP... OF PHILOSOPHY May 2010 Major Subject: Mechanical Engineering HP -SPECTRAL METHODS FOR STRUCTURAL MECHANICS AND FLUID DYNAMICS PROBLEMS A Dissertation by RAKESH RANJAN Submitted to the Office of Graduate Studies of Texas A&M University in partial...
D. M. McEligot; K.G. Condie; G. E. Mc Creery; H. M. Mc Ilroy
2005-09-01T23:59:59.000Z
The objective of the present report is to document the design of our first experiment to measure generic flow phenomena expected to occur in the lower plenum of a typical prismatic VHTR (Very High Temperature Reactor) concept. In the process, fabrication sketches are provided for the use of CFD (computational fluid dynamics) analysts wishing to employ the data for assessment of their proposed codes. The general approach of the project is to develop new benchmark experiments for assessment in parallel with CFD and coupled CFD/systems code calculations for the same geometry. One aspect of the complex flow in a prismatic VHTR is being addressed: flow and thermal mixing in the lower plenum ("hot streaking" issue). Current prismatic VHTR concepts were examined to identify their proposed flow conditions and geometries over the range from normal operation to decay heat removal in a pressurized cooldown. Approximate analyses were applied to determine key non-dimensional parameters and their magnitudes over this operating range. The flow in the lower plenum can locally be considered to be a situation of multiple jets into a confined crossflow -- with obstructions. Flow is expected to be turbulent with momentum-dominated turbulent jets entering; buoyancy influences are estimated to be negligible in normal full power operation. Experiments are needed for the combined features of the lower plenum flows. Missing from the typical jet experiments available are interactions with nearby circular posts and with vertical posts in the vicinity of vertical walls - with near stagnant surroundings at one extreme and significant crossflow at the other.
A covariant action principle for dissipative fluid dynamics: From formalism to fundamental physics
N. Andersson; G. L. Comer
2015-05-18T23:59:59.000Z
We present a new variational framework for dissipative general relativistic fluid dynamics. The model extends the convective variational principle for multi-fluid systems to account for a range of dissipation channels. The key ingredients in the construction are i) the use of a lower dimensional matter space for each fluid component, and ii) an extended functional dependence for the associated volume forms. In an effort to make the concepts clear, the formalism is developed in steps with the model example of matter coupled to heat considered at each level. Thus we discuss a model for heat flow, derive the relativistic Navier-Stokes equations and discuss why the individual dissipative stress tensors need not be spacetime symmetric. We argue that the new formalism, which notably does not involve an expansion away from an assumed equilibrium state, provides a conceptual breakthrough in this area of research and provide an ambitious list of directions in which one may want to extend it in the future. This involves an exciting set of problems, relating to both applications and foundational issues.
Grant L. Hawkes; James E. O'Brien; Greg Tao
2011-11-01T23:59:59.000Z
A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis cell performance and steam electrolysis in an internally manifolded planar solid oxide electrolysis cell (SOEC) stack. This design is being evaluated at the Idaho National Laboratory for hydrogen production from nuclear power and process heat. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, operating potential, steam-electrode gas composition, oxygen-electrode gas composition, current density and hydrogen production over a range of stack operating conditions. Single-cell and five-cell results will be presented. Flow distribution through both models is discussed. Flow enters from the bottom, distributes through the inlet plenum, flows across the cells, gathers in the outlet plenum and flows downward making an upside-down ''U'' shaped flow pattern. Flow and concentration variations exist downstream of the inlet holes. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Effects of variations in operating temperature, gas flow rate, oxygen-electrode and steam-electrode current density, and contact resistance from the base case are presented. Contour plots of local electrolyte temperature, current density, and Nernst potential indicate the effects of heat transfer, reaction cooling/heating, and change in local gas composition. Results are discussed for using this design in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production, cell thermal efficiency, cell electrical efficiency, and Gibbs free energy are discussed and reported herein.
Transient Temperature Modeling For Wellbore Fluid Under Static and Dynamic Conditions
Ali, Muhammad
2014-04-22T23:59:59.000Z
for geothermal wells and prediction of injection fluid temperatures. In this thesis, development and usage of three models for transient fluid temperature are presented. Two models predict transient temperature of flowing fluid under separate flow configurations...
Transient Temperature Modeling For Wellbore Fluid Under Static and Dynamic Conditions
Ali, Muhammad
2014-04-22T23:59:59.000Z
for geothermal wells and prediction of injection fluid temperatures. In this thesis, development and usage of three models for transient fluid temperature are presented. Two models predict transient temperature of flowing fluid under separate flow configurations...
Notes 10. A thermohydrodynamic bulk-flow model for fluid film bearings
San Andres, Luis
2009-01-01T23:59:59.000Z
The complete set of bulk-flow equations for the analysis of turbulent flow fluid film bearings. Importance of thermal effects in process fluid applications. A CFD method for solution of the bulk-flow equations....
Fabrizio Clarelli; Cristiana Di Russo; Roberto Natalini; Magali Ribot
2014-08-09T23:59:59.000Z
In this article, we study in details the fluid dynamics system proposed in Clarelli et al (2013) to model the formation of cyanobacteria biofilms. After analyzing the linear stability of the unique non trivial equilibrium of the system, we introduce in the model the influence of light and temperature, which are two important factors for the development of cyanobacteria biofilm. Since the values of the coefficients we use for our simulations are estimated through information found in the literature, some sensitivity and robustness analyses on these parameters are performed. All these elements enable us to control and to validate the model we have already derived and to present some numerical simulations in the 2D and the 3D cases.
Oelfke, John Barry; Torczynski, John Robert; O'Hern, Timothy John; Tortora, Paul Richard; Bhusarapu, Satish (; ); Trujillo, Steven Mathew
2006-08-01T23:59:59.000Z
An experimental program was conducted to study the multiphase gas-solid flow in a pilot-scale circulating fluidized bed (CFB). This report describes the CFB experimental facility assembled for this program, the diagnostics developed and/or applied to make measurements in the riser section of the CFB, and the data acquired for several different flow conditions. Primary data acquired included pressures around the flow loop and solids loadings at selected locations in the riser. Tomographic techniques using gamma radiation and electrical capacitance were used to determine radial profiles of solids volume fraction in the riser, and axial profiles of the integrated solids volume fraction were produced. Computer Aided Radioactive Particle Tracking was used to measure solids velocities, fluxes, and residence time distributions. In addition, a series of computational fluid dynamics simulations was performed using the commercial code Arenaflow{trademark}.
A numerical study of longtime dynamics and ergodic-nonergodic transitions in dense simple fluids
David D. McCowan
2014-11-04T23:59:59.000Z
For over 30 years, mode-coupling theory (MCT) has been the de facto theoretic description of dense fluids and the liquid-glass transition. MCT, however, is limited by its ad hoc construction and lacks a mechanism to institute corrections. We use recent results from a new theoretical framework--developed from first principles via a self-consistent perturbation expansion in terms of an effective two-body potential--to numerically explore the kinetics of systems of classical particles, specifically hard spheres obeying Smoluchowski dynamics. We present here a full solution to the kinetic equation governing the density-density time correlation function and show that the function exhibits the characteristic two-step decay of supercooled fluids and an ergodic-nonergodic transition to a dynamically-arrested state. Unlike many previous numerical studies and experiments, we have access to the full time and wavenumber range of the correlation function and can track the solution unprecedentedly close to the transition, covering nearly 15 decades of time. Using asymptotic approximation techniques developed for MCT, we fit the solution to predicted forms and extract critical parameters. Our solution shows a transition at packing fraction $\\eta^*=0.60149761(10)$--consistent with previous static solutions under this theory and with comparable colloidal suspension experiments--and the behavior in the $\\beta$-relaxation regime is fit to power-law decays with critical exponents $a=0.375(3)$ and $b=0.8887(4)$, and with $\\lambda=0.5587(18)$. For the $\\alpha$-relaxation of the ergodic phase, we find a power-law divergence of the time scale $\\tau_{\\alpha}$ as we approach the transition. Through these results, we establish that this new theory is able to reproduce the salient features of MCT, but has the advantages of a first principles derivation and a clear mechanism for making systematic improvements.
Fluid Dynamics Research 40 (2008) 3444 A mixer design for the pigtail braid
Balasuriya, Sanjeeva
2008-01-01T23:59:59.000Z
, 2002) that even laminar fluid flows can stir a fluid effectively, provided that the Lagrangian particle baffles may be replaced by flow structures (such as periodic islands). © 2006 The Japan Society of Fluid Mechanics and Elsevier B.V. All rights reserved. Keywords: Chaotic advection; Braid; Stokes flow; Fluid
Lotko, William
by the soft electron precipitation to topside altitudes, where the wave-driven transverse ion heating pumps transport, wave heating, hybrid simulation Citation: Wu, X.-Y., J. L. Horwitz, and J.-N. Tu, Dynamic fluid potentials, transverse ion heating, and soft electron precipitation X.-Y. Wu, J. L. Horwitz, and J.-N. Tu
Combes, Stacey A.
Swimming and flying animals generate fluid-dynamic forces by flapping flexible appendages such as wings or fins. The stresses generated by motions of these structures can be resolved into vertical aerial and aquatic animals that propel themselves with wing-like appendages generate these vertical
Chen, Qingyan "Yan"
Fast and Informative Flow Simulations in a Building by Using Fast Fluid Dynamics Model on Graphics simulations are necessary for building emergency management, preliminary design of sustainable buildings for a whole building. This paper reports our efforts on further accelerating FFD simulation by running
Donna Post Guillen; Daniel S. Wendt; Steven P. Antal; Michael Z. Podowski
2007-11-01T23:59:59.000Z
The purpose of this paper is to document the review of several open-literature sources of both experimental capabilities and published hydrodynamic data to aid in the validation of a Computational Fluid Dynamics (CFD) based model of a slurry bubble column (SBC). The review included searching the Web of Science, ISI Proceedings, and Inspec databases, internet searches as well as other open literature sources. The goal of this study was to identify available experimental facilities and relevant data. Integral (i.e., pertaining to the SBC system), as well as fundamental (i.e., separate effects are considered), data are included in the scope of this effort. The fundamental data is needed to validate the individual mechanistic models or closure laws used in a Computational Multiphase Fluid Dynamics (CMFD) simulation of a SBC. The fundamental data is generally focused on simple geometries (i.e., flow between parallel plates or cylindrical pipes) or custom-designed tests to focus on selected interfacial phenomena. Integral data covers the operation of a SBC as a system with coupled effects. This work highlights selected experimental capabilities and data for the purpose of SBC model validation, and is not meant to be an exhaustive summary.
Donna Post Guillen; Daniel S. Wendt
2007-11-01T23:59:59.000Z
The purpose of this paper is to document the review of several open-literature sources of both experimental capabilities and published hydrodynamic data to aid in the validation of a Computational Fluid Dynamics (CFD) based model of a slurry bubble column (SBC). The review included searching the Web of Science, ISI Proceedings, and Inspec databases, internet searches as well as other open literature sources. The goal of this study was to identify available experimental facilities and relevant data. Integral (i.e., pertaining to the SBC system), as well as fundamental (i.e., separate effects are considered), data are included in the scope of this effort. The fundamental data is needed to validate the individual mechanistic models or closure laws used in a Computational Multiphase Fluid Dynamics (CMFD) simulation of a SBC. The fundamental data is generally focused on simple geometries (i.e., flow between parallel plates or cylindrical pipes) or custom-designed tests to focus on selected interfacial phenomena. Integral data covers the operation of a SBC as a system with coupled effects. This work highlights selected experimental capabilities and data for the purpose of SBC model validation, and is not meant to be an exhaustive summary.
Multiscale CFD simulations of entrained flow gasification
Kumar, Mayank, Ph. D. Massachusetts Institute of Technology
2011-01-01T23:59:59.000Z
The design of entrained flow gasifiers and their operation has largely been an experience based enterprise. Most, if not all, industrial scale gasifiers were designed before it was practical to apply CFD models. Moreover, ...
Development of CFD models to support LEU Conversion of ORNL s High Flux Isotope Reactor
Khane, Vaibhav B [ORNL] [ORNL; Jain, Prashant K [ORNL] [ORNL; Freels, James D [ORNL] [ORNL
2012-01-01T23:59:59.000Z
The US Department of Energy s National Nuclear Security Administration (NNSA) is participating in the Global Threat Reduction Initiative to reduce and protect vulnerable nuclear and radiological materials located at civilian sites worldwide. As an integral part of one of NNSA s subprograms, Reduced Enrichment for Research and Test Reactors, HFIR is being converted from the present HEU core to a low enriched uranium (LEU) core with less than 20% of U-235 by weight. Because of HFIR s importance for condensed matter research in the United States, its conversion to a high-density, U-Mo-based, LEU fuel should not significantly impact its existing performance. Furthermore, cost and availability considerations suggest making only minimal changes to the overall HFIR facility. Therefore, the goal of this conversion program is only to substitute LEU for the fuel type in the existing fuel plate design, retaining the same number of fuel plates, with the same physical dimensions, as in the current HFIR HEU core. Because LEU-specific testing and experiments will be limited, COMSOL Multiphysics was chosen to provide the needed simulation capability to validate against the HEU design data and previous calculations, and predict the performance of the proposed LEU fuel for design and safety analyses. To achieve it, advanced COMSOL-based multiphysics simulations, including computational fluid dynamics (CFD), are being developed to capture the turbulent flows and associated heat transfer in fine detail and to improve predictive accuracy [2].
Pre-test CFD Calculations for a Bypass Flow Standard Problem
Rich Johnson
2011-11-01T23:59:59.000Z
The bypass flow in a prismatic high temperature gas-cooled reactor (HTGR) is the flow that occurs between adjacent graphite blocks. Gaps exist between blocks due to variances in their manufacture and installation and because of the expansion and shrinkage of the blocks from heating and irradiation. Although the temperature of fuel compacts and graphite is sensitive to the presence of bypass flow, there is great uncertainty in the level and effects of the bypass flow. The Next Generation Nuclear Plant (NGNP) program at the Idaho National Laboratory has undertaken to produce experimental data of isothermal bypass flow between three adjacent graphite blocks. These data are intended to provide validation for computational fluid dynamic (CFD) analyses of the bypass flow. Such validation data sets are called Standard Problems in the nuclear safety analysis field. Details of the experimental apparatus as well as several pre-test calculations of the bypass flow are provided. Pre-test calculations are useful in examining the nature of the flow and to see if there are any problems associated with the flow and its measurement. The apparatus is designed to be able to provide three different gap widths in the vertical direction (the direction of the normal coolant flow) and two gap widths in the horizontal direction. It is expected that the vertical bypass flow will range from laminar to transitional to turbulent flow for the different gap widths that will be available.
B. D. Nichols; C. Müller; G. A. Necker; J. R. Travis; J. W. Spore; K. L. Lam; P. Royl; T. L. Wilson
1998-10-01T23:59:59.000Z
Los Alamos National Laboratory (LANL) and Forschungszentrum Karlsruhe (FzK) are developing GASFLOW, a three-dimensional (3D) fluid dynamics field code as a best-estimate tool to characterize local phenomena within a flow field. Examples of 3D phenomena include circulation patterns; flow stratification; hydrogen distribution mixing and stratification; combustion and flame propagation; effects of noncondensable gas distribution on local condensation and evaporation; and aerosol entrainment, transport, and deposition. An analysis with GASFLOW will result in a prediction of the gas composition and discrete particle distribution in space and time throughout the facility and the resulting pressure and temperature loadings on the walls and internal structures with or without combustion. A major application of GASFLOW is for predicting the transport, mixing, and combustion of hydrogen and other gases in nuclear reactor containment and other facilities. It has been applied to situations involving transporting and distributing combustible gas mixtures. It has been used to study gas dynamic behavior in low-speed, buoyancy-driven flows, as well as sonic flows or diffusion dominated flows; and during chemically reacting flows, including deflagrations. The effects of controlling such mixtures by safety systems can be analyzed. The code version described in this manual is designated GASFLOW 2.1, which combines previous versions of the United States Nuclear Regulatory Commission code HMS (for Hydrogen Mixing Studies) and the Department of Energy and FzK versions of GASFLOW. The code was written in standard Fortran 90. This manual comprises three volumes. Volume I describes the governing physical equations and computational model. Volume II describes how to use the code to set up a model geometry, specify gas species and material properties, define initial and boundary conditions, and specify different outputs, especially graphical displays. Sample problems are included. Volume III contains some of the assessments performed by LANL and FzK.
Shin, S.; Abdelall, F.; Juric, D.; Abdel-Khalik, S.I.; Yoda, M.; Sadowski, D. [Georgia Institute of Technology (United States)
2003-05-15T23:59:59.000Z
A numerical and experimental investigation has been conducted to analyze the fluid dynamic aspects of the porous wetted wall protection scheme for inertial fusion energy (IFE) reactor first walls. A level contour reconstruction method has been used to track the three-dimensional evolution of the liquid film surface on porous downward-facing walls with different initial film thickness, liquid injection velocity through the porous wall, surface disturbance amplitude, configuration and mode number, liquid properties, and surface inclination angle. Generalized charts for the computed droplet detachment time, detached droplet equivalent diameter, and minimum film thickness during the transient for various design parameters and coolant properties are presented.In order to validate the numerical results over a wide range of parameters, an experimental test facility has been designed and constructed to simulate the hydrodynamics of downward-facing porous wetted walls. Nondimensionalization of the model shows that water can be adequately used as a simulant to validate the numerical results. Preliminary experimental results show good agreement with model predictions. The results of this investigation should allow designers of conceptual IFE reactors to identify appropriate 'windows' for successful operation of the porous wetted wall protection concept for different coolants.
Wind Turbine Modeling for Computational Fluid Dynamics: December 2010 - December 2012
Tossas, L. A. M.; Leonardi, S.
2013-07-01T23:59:59.000Z
With the shortage of fossil fuel and the increasing environmental awareness, wind energy is becoming more and more important. As the market for wind energy grows, wind turbines and wind farms are becoming larger. Current utility-scale turbines extend a significant distance into the atmospheric boundary layer. Therefore, the interaction between the atmospheric boundary layer and the turbines and their wakes needs to be better understood. The turbulent wakes of upstream turbines affect the flow field of the turbines behind them, decreasing power production and increasing mechanical loading. With a better understanding of this type of flow, wind farm developers could plan better-performing, less maintenance-intensive wind farms. Simulating this flow using computational fluid dynamics is one important way to gain a better understanding of wind farm flows. In this study, we compare the performance of actuator disc and actuator line models in producing wind turbine wakes and the wake-turbine interaction between multiple turbines. We also examine parameters that affect the performance of these models, such as grid resolution, the use of a tip-loss correction, and the way in which the turbine force is projected onto the flow field.
Gustavsen, Arlid
2008-01-01T23:59:59.000Z
be used to calculate radiation heat transfer. The convectionat about 5×10 -10 ). Radiation heat transfer was included inof rays in the radiation heat-transfer algorithm of the CFD
Thomas, J. W.; Fanning, T. H.; Vilim, R.; Briggs, L. L. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439-4842 (United States)
2012-07-01T23:59:59.000Z
Recent analyses have demonstrated the need to model multidimensional phenomena, particularly thermal stratification in outlet plena, during safety analyses of loss-of-flow transients of certain liquid-metal cooled reactor designs. Therefore, Argonne's reactor systems safety code SAS4A/SASSYS-1 is being enhanced by integrating 3D computational fluid dynamics models of the plena. A validation exercise of the new tool is being performed by analyzing the protected loss-of-flow event demonstrated by the EBR-II Shutdown Heat Removal Test 17. In this analysis, the behavior of the coolant in the cold pool is modeled using the CFD code STAR-CCM+, while the remainder of the cooling system and the reactor core are modeled with SAS4A/SASSYS-1. This paper summarizes the code integration strategy and provides the predicted 3D temperature and velocity distributions inside the cold pool during SHRT-17. The results of the coupled analysis should be considered preliminary at this stage, as the exercise pointed to the need to improve the CFD model of the cold pool tank. (authors)
Development of a Prototype Lattice Boltzmann Code for CFD of Fusion Systems.
Pattison, Martin J; Premnath, Kannan N; Banerjee, Sanjoy; Dwivedi, Vinay
2007-02-26T23:59:59.000Z
Designs of proposed fusion reactors, such as the ITER project, typically involve the use of liquid metals as coolants in components such as heat exchangers, which are generally subjected to strong magnetic fields. These fields induce electric currents in the fluids, resulting in magnetohydrodynamic (MHD) forces which have important effects on the flow. The objective of this SBIR project was to develop computational techniques based on recently developed lattice Boltzmann techniques for the simulation of these MHD flows and implement them in a computational fluid dynamics (CFD) code for the study of fluid flow systems encountered in fusion engineering. The code developed during this project, solves the lattice Boltzmann equation, which is a kinetic equation whose behaviour represents fluid motion. This is in contrast to most CFD codes which are based on finite difference/finite volume based solvers. The lattice Boltzmann method (LBM) is a relatively new approach which has a number of advantages compared with more conventional methods such as the SIMPLE or projection method algorithms that involve direct solution of the Navier-Stokes equations. These are that the LBM is very well suited to parallel processing, with almost linear scaling even for very large numbers of processors. Unlike other methods, the LBM does not require solution of a Poisson pressure equation leading to a relatively fast execution time. A particularly attractive property of the LBM is that it can handle flows in complex geometries very easily. It can use simple rectangular grids throughout the computational domain -- generation of a body-fitted grid is not required. A recent advance in the LBM is the introduction of the multiple relaxation time (MRT) model; the implementation of this model greatly enhanced the numerical stability when used in lieu of the single relaxation time model, with only a small increase in computer time. Parallel processing was implemented using MPI and demonstrated the ability of the LBM to scale almost linearly. The equation for magnetic induction was also solved using a lattice Boltzmann method. This approach has the advantage that it fits in well to the framework used for the hydrodynamic equations, but more importantly that it preserves the ability of the code to run efficiently on parallel architectures. Since the LBM is a relatively recent model, a number of new developments were needed to solve the magnetic induction equation for practical problems. Existing methods were only suitable for cases where the fluid viscosity and the magnetic resistivity are of the same order, and a preconditioning method was used to allow the simulation of liquid metals, where these properties differ by several orders of magnitude. An extension of this method to the hydrodynamic equations allowed faster convergence to steady state. A new method of imposing boundary conditions using an extrapolation technique was derived, enabling the magnetic field at a boundary to be specified. Also, a technique by which the grid can be stretched was formulated to resolve thin layers at high imposed magnetic fields, allowing flows with Hartmann numbers of several thousand to be quickly and efficiently simulated. In addition, a module has been developed to calculate the temperature field and heat transfer. This uses a total variation diminishing scheme to solve the equations and is again very amenable to parallelisation. Although, the module was developed with thermal modelling in mind, it can also be applied to passive scalar transport. The code is fully three dimensional and has been applied to a wide variety of cases, including both laminar and turbulent flows. Validations against a series of canonical problems involving both MHD effects and turbulence have clearly demonstrated the ability of the LBM to properly model these types of flow. As well as applications to fusion engineering, the resulting code is flexible enough to be applied to a wide range of other flows, in particular those requiring parallel computations with many processors. For example, at
Soto, Enrique
2013-01-01T23:59:59.000Z
This fluid dynamics video is an entry for the Gallery of Fluid Motion for the 66th Annual Meeting of the Fluid Dynamics Division of the American Physical Society. We show the curious behaviour of a light ball interacting with a liquid jet. For certain conditions, a ball can be suspended into a slightly inclined liquid jet. We studied this phenomenon using a high speed camera. The visualizations show that the object can be `juggled' for a variety of flow conditions. A simple calculation showed that the ball remains at a stable position due to a Bernoulli-like effect. The phenomenon is very stable and easy to reproduce.
Huang, Zhiming
2012-07-16T23:59:59.000Z
and gas exploration and developments have been moving fast toward increasingly deeper water depth, i.e. 3,000m in Gulf of Mexico. Majority of the subsea wells are tied back to a surface platform through long risers, including steel catenary risers..., flexible risers, free standing risers, bundled risers, or top tensioned risers (ASME B31.4, 2002, ASME B31.8a, 2001, API 1111, 1999). These risers provide fluid conduit for fluid transport between subsea wells and surface platform, and protect...
Grant Hawkes; James E. O'Brien
2008-10-01T23:59:59.000Z
A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis cell performance and steam electrolysis in a new novel integrated planar porous-tube supported solid oxide electrolysis cell (SOEC). The model is of several integrated planar cells attached to a ceramic support tube. This design is being evaluated with modeling at the Idaho National Laboratory. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, activation over-potential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Mean per-cell area-specific-resistance (ASR) values decrease with increasing current density. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Effects of variations in operating temperature, gas flow rate, cathode and anode exchange current density, and contact resistance from the base case are presented. Contour plots of local electrolyte temperature, current density, and Nernst potential indicated the effects of heat transfer, reaction cooling/heating, and change in local gas composition. Results are discussed for using this design in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production, cell thermal efficiency, cell electrical efficiency, and Gibbs free energy are discussed and reported herein.
Real-time POD-CFD Wind-Load Calculator for PV Systems
Huayamave, Victor [Centecorp; Divo, Eduardo [Centecorp; Ceballos, Andres [Centecorp; Barriento, Carolina [Centecorp; Stephen, Barkaszi [FSEC; Hubert, Seigneur [FSEC
2014-03-21T23:59:59.000Z
The primary objective of this project is to create an accurate web-based real-time wind-load calculator. This is of paramount importance for (1) the rapid and accurate assessments of the uplift and downforce loads on a PV mounting system, (2) identifying viable solutions from available mounting systems, and therefore helping reduce the cost of mounting hardware and installation. Wind loading calculations for structures are currently performed according to the American Society of Civil Engineers/ Structural Engineering Institute Standard ASCE/SEI 7; the values in this standard were calculated from simplified models that do not necessarily take into account relevant characteristics such as those from full 3D effects, end effects, turbulence generation and dissipation, as well as minor effects derived from shear forces on installation brackets and other accessories. This standard does not include provisions that address the special requirements of rooftop PV systems, and attempts to apply this standard may lead to significant design errors as wind loads are incorrectly estimated. Therefore, an accurate calculator would be of paramount importance for the preliminary assessments of the uplift and downforce loads on a PV mounting system, identifying viable solutions from available mounting systems, and therefore helping reduce the cost of the mounting system and installation. The challenge is that although a full-fledged three-dimensional computational fluid dynamics (CFD) analysis would properly and accurately capture the complete physical effects of air flow over PV systems, it would be impractical for this tool, which is intended to be a real-time web-based calculator. CFD routinely requires enormous computation times to arrive at solutions that can be deemed accurate and grid-independent even in powerful and massively parallel computer platforms. This work is expected not only to accelerate solar deployment nationwide, but also help reach the SunShot Initiative goals of reducing the total installed cost of solar energy systems by 75%. The largest percentage of the total installed cost of solar energy system is associated with balance of system cost, with up to 40% going to “soft” costs; which include customer acquisition, financing, contracting, permitting, interconnection, inspection, installation, performance, operations, and maintenance. The calculator that is being developed will provide wind loads in real-time for any solar system designs and suggest the proper installation configuration and hardware; and therefore, it is anticipated to reduce system design, installation and permitting costs.
Dynamics and microstructure of colloidal complex fluids: a lattice Boltzmann study
Kim, Eunhye
2009-01-01T23:59:59.000Z
The lattice Boltzmann (LB) method is a versatile way to model complex fluids with hydrodynamic interactions through solving the Navier-Stokes equations. It is well-known that the role of hydrodynamic interactions is ...
Characterization of Filter Cake Buildup and Cleanup under Dynamic Fluid Loss Conditions
Yango, Takwe
2011-10-21T23:59:59.000Z
. The fracturing fluid gets dehydrated under pressure leaving behind a highly concentrated unbroken residue called filter cake which causes permeability impairment in the proppant pack, resulting in low fracture conductivity and decreased effective fracture length...
Fluid Dynamics Models for Low Rank Discriminant Analysis Yung-Kyun Noh1,2
and velocity flow fields. We show how to apply the Gauss principle of least con- straint in fluids to obtain., 2000). Projection pursuit is a canonical approach to find a low dimen- sional subspace where
Characterization of Filter Cake Buildup and Cleanup under Dynamic Fluid Loss Conditions
Yango, Takwe
2011-10-21T23:59:59.000Z
. The fracturing fluid gets dehydrated under pressure leaving behind a highly concentrated unbroken residue called filter cake which causes permeability impairment in the proppant pack, resulting in low fracture conductivity and decreased effective fracture length...
Robert E. Spall; Barton Smith; Thomas Hauser
2008-12-08T23:59:59.000Z
Nationwide, the demand for electricity due to population and industrial growth is on the rise. However, climate change and air quality issues raise serious questions about the wisdom of addressing these shortages through the construction of additional fossil fueled power plants. In 1997, the President's Committee of Advisors on Science and Technology Energy Research and Development Panel determined that restoring a viable nuclear energy option was essential and that the DOE should implement a R&D effort to address principal obstacles to achieving this option. This work has addressed the need for improved thermal/fluid analysis capabilities, through the use of computational fluid dynamics, which are necessary to support the design of generation IV gas-cooled and supercritical water reactors.
CFD-based Optimization for Automotive Aerodynamics
Dumas, Laurent
Chapter 1 CFD-based Optimization for Automotive Aerodynamics Laurent Dumas Abstract The car drag- ments. An overview of the main characteristics of automotive aerodynamics and a detailed presentation.dumas@upmc.fr) 1 #12;2 Laurent Dumas 1.1 Introducing Automotive Aerodynamics 1.1.1 A Major Concern for Car
Fabio Leoni; Giancarlo Franzese
2014-06-08T23:59:59.000Z
Confinement can modify the dynamics, the thermodynamics and the structural properties of liquid water, the prototypical anomalous liquid. By considering a general anomalous liquid, suitable for globular proteins, colloids or liquid metals, we study by molecular dynamics simulations the effect of a solvophilic structured and a solvophobic unstructured wall on the phases, the crystal nucleation and the dynamics of the fluid. We find that at low temperatures the large density of the solvophilic wall induces a high-density, high-energy structure in the first layer ("tempting" effect). In turn, the first layer induces a "molding" effect on the second layer determining a structure with reduced energy and density, closer to the average density of the system. This low-density, low-energy structure propagates further through the layers by templating effect and can involve all the existing layers at the lowest temperatures investigated. Therefore, although the high-density, high-energy structure does not self-reproduce further than the first layer, the structured wall can have a long-range effect thanks to a sequence of templating, molding and templating effects through the layers. We find dynamical slowing down of the solvent near the solvophilic wall but with largely heterogeneous dynamics near the wall due to superdiffusive liquid veins within a frozen matrix of solvent. Hence, the partial freezing of the first hydration layer does not correspond necessarily to an effective reduction of the channel section in terms of transport properties.
Solom, Matthew 1985-
2012-12-10T23:59:59.000Z
of laser-induced cavitation in a seeded fluid, and demonstrated some of the associated limitations as well. In addition, the CFD framework developed here can be used to cross-compare experimental results with computer simulations as well...
Mottram, Nigel
://www.archie-west.ac.uk/for-industry/workshop-registration Recent government reports have concluded that High Performance Computing has the potential to add 3 needs. Programme 13:00 Lunch 14:00 Welcome, Dr Paul Mulheran High Performance Computing & CFD at Expro
Z .Dynamics of Atmospheres and Oceans 28 1998 93105 Fluid transport by dipolar vortices
Flór, Jan-Bert
with a model based on characterising the flow around the dipole as irrotational flow past a rigid cylinder on hydrodynamics. Proc. Cambridge Philos. Soc., 49, 342354 , namely that the vortex will displace a volume C VV experience a drag force essentially because they Ztransport fluid forward as they rise, distorting isopycnal
MODELING STRATEGIES TO COMPUTE NATURAL CIRCULATION USING CFD IN A VHTR AFTER A LOFA
Yu-Hsin Tung; Richard W. Johnson; Ching-Chang Chieng; Yuh-Ming Ferng
2012-11-01T23:59:59.000Z
A prismatic gas-cooled very high temperature reactor (VHTR) is being developed under the next generation nuclear plant program (NGNP) of the U.S. Department of Energy, Office of Nuclear Energy. In the design of the prismatic VHTR, hexagonal shaped graphite blocks are drilled to allow insertion of fuel pins, made of compacted TRISO fuel particles, and coolant channels for the helium coolant. One of the concerns for the reactor design is the effects of a loss of flow accident (LOFA) where the coolant circulators are lost for some reason, causing a loss of forced coolant flow through the core. In such an event, it is desired to know what happens to the (reduced) heat still being generated in the core and if it represents a problem for the fuel compacts, the graphite core or the reactor vessel (RV) walls. One of the mechanisms for the transport of heat out of the core is by the natural circulation of the coolant, which is still present. That is, how much heat may be transported by natural circulation through the core and upwards to the top of the upper plenum? It is beyond current capability for a computational fluid dynamic (CFD) analysis to perform a calculation on the whole RV with a sufficiently refined mesh to examine the full potential of natural circulation in the vessel. The present paper reports the investigation of several strategies to model the flow and heat transfer in the RV. It is found that it is necessary to employ representative geometries of the core to estimate the heat transfer. However, by taking advantage of global and local symmetries, a detailed estimate of the strength of the resulting natural circulation and the level of heat transfer to the top of the upper plenum is obtained.
Phase-Contrast MRI and CFD Modeling of Apparent 3He Gas Flow in Rat Pulmonary Airways
Minard, Kevin R.; Kuprat, Andrew P.; Kabilan, Senthil; Jacob, Rick E.; Einstein, Daniel R.; Carson, James P.; Corley, Richard A.
2012-08-01T23:59:59.000Z
Phase-contrast (PC) magnetic resonance imaging (MRI) with hyperpolarized 3He is potentially useful for developing and testing patient-specific models of pulmonary airflow. One challenge, however, is that PC-MRI provides apparent values of local 3He velocity that not only depend on actual airflow but also on gas diffusion. This not only blurs laminar flow patterns in narrow airways but also introduces anomalous airflow structure that reflects gas-wall interactions. Here, both effects are predicted in a live rat using computational fluid dynamics (CFD), and for the first time, simulated patterns of apparent 3He gas velocity are compared with in-vivo PC-MRI. Results show (1) that correlations (R2) between measured and simulated airflow patterns increase from 0.23 to 0.79 simply by accounting for apparent 3He transport, and that (2) remaining differences are mainly due to uncertain airway segmentation and partial volume effects stemming from relatively coarse MRI resolution. Higher-fidelity testing of pulmonary airflow predictions should therefore be possible with future imaging improvements.
User's manual for PELE3D: a computer code for three-dimensional incompressible fluid dynamics
McMaster, W H
1982-05-07T23:59:59.000Z
The PELE3D code is a three-dimensional semi-implicit Eulerian hydrodynamics computer program for the solution of incompressible fluid flow coupled to a structure. The fluid and coupling algorithms have been adapted from the previously developed two-dimensional code PELE-IC. The PELE3D code is written in both plane and cylindrical coordinates. The coupling algorithm is general enough to handle a variety of structural shapes. The free surface algorithm is able to accommodate a top surface and several independent bubbles. The code is in a developmental status since all the intended options have not been fully implemented and tested. Development of this code ended in 1980 upon termination of the contract with the Nuclear Regulatory Commission.
Effects of drilling fluid properties and shear rate on dynamic filtration
McCarty, Robert Andrew
1990-01-01T23:59:59.000Z
be used to eliminate the residual fines left behind from the previous mud run. 2. Synthetic cores should be used to increase reproducibility and homogeneity. This will further separate core properties from mud filter cake properties allowing a more... are subjected to a differential pressure across porous and permeable formations. Differential pressure causes solids in drilling fluids to be filtered out and deposited as a cake on the wellbore wall as the liquid phase (mud filtrate) invades the formation...
Leoni, Fabio; Franzese, Giancarlo [Departament de Fisica Fonamental, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain)
2014-11-07T23:59:59.000Z
Confinement can modify the dynamics, the thermodynamics, and the structural properties of liquid water, the prototypical anomalous liquid. By considering a generic model for anomalous liquids, suitable for describing solutions of globular proteins, colloids, or liquid metals, we study by molecular dynamics simulations the effect that an attractive wall with structure and a repulsive wall without structure have on the phases, the crystal nucleation, and the dynamics of the fluid. We find that at low temperatures the large density of the attractive wall induces a high-density, high-energy structure in the first layer (“templating” effect). In turn, the first layer induces a “molding” effect on the second layer determining a structure with reduced energy and density, closer to the average density of the system. This low-density, low-energy structure propagates further through the layers by templating effect and can involve all the existing layers at the lowest temperatures investigated. Therefore, although the high-density, high-energy structure does not self-reproduce further than the first layer, the structured wall can have a long-range influence thanks to a sequence of templating, molding, and templating effects through the layers. We find that the walls also have an influence on the dynamics of the liquid, with a stronger effect near the attractive wall. In particular, we observe that the dynamics is largely heterogeneous (i) among the layers, as a consequence of the sequence of structures caused by the walls presence, and (ii) within the same layer, due to superdiffusive liquid veins within a frozen matrix of particles near the walls at low temperature and high density. Hence, the partial freezing of the first layer does not correspond necessarily to an effective reduction of the channel's section in terms of transport properties, as suggested by other authors.
Stokesian dynamic simulations and analyses of interfacial and bulk colloidal fluids
Anekal, Samartha Guha
2006-10-30T23:59:59.000Z
, and hydrodynamic forces to model dynamics of colloidal dispersions. In addition, we develop theoretical expressions for quantifying self-diffusion in colloids interacting via different particle-particle and particle-wall potentials. Specifically, we have used...
Analogies of Ocean/Atmosphere Rotating Fluid Dynamics with Gyroscopes: Teaching Opportunities
Haine, Thomas W. N.
The dynamics of the rotating shallow-water (RSW) system include geostrophic f low and inertial oscillation. These classes of motion are ubiquitous in the ocean and atmosphere. They are often surprising to people at first ...
CFD Combustion Modeling with Conditional Moment Closure using...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Combustion Modeling with Conditional Moment Closure using Tabulated Chemistry CFD Combustion Modeling with Conditional Moment Closure using Tabulated Chemistry A method is...
Rahatgaonkar, P. S.; Datta, D.; Malhotra, P. K.; Ghadge, S. G. [Nuclear Power Corporation of India Ltd., R-2, Ent. Block, Nabhikiya Urja Bhavan, Anushakti Nagar, Mumbai - 400 094 (India)
2012-07-01T23:59:59.000Z
Prediction of groundwater movement and contaminant transport in soil is an important problem in many branches of science and engineering. This includes groundwater hydrology, environmental engineering, soil science, agricultural engineering and also nuclear engineering. Specifically, in nuclear engineering it is applicable in the design of spent fuel storage pools and waste management sites in the nuclear power plants. Ground water modeling involves the simulation of flow and contaminant transport by groundwater flow. In the context of contaminated soil and groundwater system, numerical simulations are typically used to demonstrate compliance with regulatory standard. A one-dimensional Computational Fluid Dynamics code GFLOW had been developed based on the Finite Difference Method for simulating groundwater flow and contaminant transport through saturated and unsaturated soil. The code is validated with the analytical model and the benchmarking cases available in the literature. (authors)
Ghobadi, Ahmadreza F.; Elliott, J. Richard, E-mail: elliot1@uakron.edu [Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325 (United States)
2013-12-21T23:59:59.000Z
In this work, we aim to develop a version of the Statistical Associating Fluid Theory (SAFT)-? equation of state (EOS) that is compatible with united-atom force fields, rather than experimental data. We rely on the accuracy of the force fields to provide the relation to experimental data. Although, our objective is a transferable theory of interfacial properties for soft and fused heteronuclear chains, we first clarify the details of the SAFT-? approach in terms of site-based simulations for homogeneous fluids. We show that a direct comparison of Helmholtz free energy to molecular simulation, in the framework of a third order Weeks-Chandler-Andersen perturbation theory, leads to an EOS that takes force field parameters as input and reproduces simulation results for Vapor-Liquid Equilibria (VLE) calculations. For example, saturated liquid density and vapor pressure of n-alkanes ranging from methane to dodecane deviate from those of the Transferable Potential for Phase Equilibria (TraPPE) force field by about 0.8% and 4%, respectively. Similar agreement between simulation and theory is obtained for critical properties and second virial coefficient. The EOS also reproduces simulation data of mixtures with about 5% deviation in bubble point pressure. Extension to inhomogeneous systems and united-atom site types beyond those used in description of n-alkanes will be addressed in succeeding papers.
Relaxation dynamics in a transient network fluid with competing gel and glass phases
Pinaki Chaudhuri; Pablo I. Hurtado; Ludovic Berthier; Walter Kob
2015-02-01T23:59:59.000Z
We use computer simulations to study the relaxation dynamics of a model for oil-in-water microemulsion droplets linked with telechelic polymers. This system exhibits both gel and glass phases and we show that the competition between these two arrest mechanisms can result in a complex, three-step decay of the time correlation functions, controlled by two different localization lengthscales. For certain combinations of the parameters, this competition gives rise to an anomalous logarithmic decay of the correlation functions and a subdiffusive particle motion, which can be understood as a simple crossover effect between the two relaxation processes. We establish a simple criterion for this logarithmic decay to be observed. We also find a further logarithmically slow relaxation related to the relaxation of floppy clusters of particles in a crowded environment, in agreement with recent findings in other models for dense chemical gels. Finally, we characterize how the competition of gel and glass arrest mechanisms affects the dynamical heterogeneities and show that for certain combination of parameters these heterogeneities can be unusually large. By measuring the four-point dynamical susceptibility, we probe the cooperativity of the motion and find that with increasing coupling this cooperativity shows a maximum before it decreases again, indicating the change in the nature of the relaxation dynamics. Our results suggest that compressing gels to large densities produces novel arrested phases that have a new and complex dynamics.
Carlisle, Bruce Scott
1994-01-01T23:59:59.000Z
AN EVAI. UATION OF THE NEUTRON RADIOGRAPHY FACILITY AT THE NUCLEAR SCIENCF- CENTER FOR DYNAMIC IMAGING OF TWO-PHASE HYDROGENOUS FLUIDS A Thesis By BRUCE SCOTT CARLlSLE Submitted to the Office of Graduate Studies of Texas Ag-M University... in partiat fulfillment of the requirements for the degree of MASTER OF SCPENCF. August 1994 Major Subject: Nuclear Engineering AN EVALUATION OF THE NEUTRON RADIOGRAPHY FACILITY AT THE NUCLEAR SCIENCE CENTFR FOR THE DYNAMIC IMAGING OF TWO...
Gable, Carl W.
, J. F. Thompson, H. Hausser and P. R. Eiseman, Engineering Research Center, Mississippi State Univ. K. Soni, J. F. Thompson, H. Hausser and P. R. Eiseman, Engineering Research Center, Mississippi Generation in Computational Fluid Dynamics and Related Fields, ed. B. K. Soni, J. F. Thompson, H. Hausser
Fluid Dynamics Seminar Fluid Dynamics Research Centre
Thomas, Peter J.
Sciences, Loughborough University) 8 th Feb. Quantifying Solute Mixing and Transport Mechanims Prof. Ian
Fluid Dynamics Seminar Fluid Dynamics Research Centre
Thomas, Peter J.
Sciences, Loughborough University) 8th Feb. Quantifying Solute Mixing and Transport Mechanims Prof. Ian
Practical issues on CFD use and some industry aspects on research with CFD
Zevenhoven, Ron
of non-catalytic NOx reduction in FBC freeboard CFD project planning Fast pyrolysis model, 18.6.2010 2-catalytic NOx reduction in FBC freeboard target: Finding optimal locations for urea injection Injections temperature for NOx reduction is between blue and red areas. Courtesy Metso Power Oy #12;Geometry Fast
Advanced Fluid Dynamics 2014 Sheet 5 Stokes flow around spherical particles
Hogg, Andrew
with no body force, where µ denotes the dynamic viscosity. Show that the stress tensor is given by ij = -2µ Ak xk ij + 2µ 2 xixj + xk 2 Ak xixj . (2) (b) Now consider the flow past a stationary sphere of radius the drag on the particle. 2. (a) Axisymmetric flow may be expressed in terms of spherical polar coordinates
Zevenhoven, Ron
difference generates forces Forces acting parallel to the flow direction are drag forces; forces acting Dynamics 424512 E #5- rz For a general surface area A (m2) perpendicular to the flow, the drag force the drag coefficient equals For flow at Re sphere, the relation CD=24/Re follows also from
Physics-Based Low Order Galerkin Models in Fluid Dynamics & Flow Control
Gorban, Alexander N.
(Berlin Institute of Technology MB1, Germany) Marek Morzynski (Poznan University of Technology, Poland models of energy supply and consumption. Yet a third principle is the realization that governing flow to time-averaged energy dynamics of Galerkin modes, and gives rise to physically based, nonlinear sub
Large-scale MR fluid dampers: modeling, and dynamic performance considerations
Spencer Jr., Billie F.
, University of Notre Dame, Notre Dame, IN 46556, USA b Lord Corporation, 110 Lord Drive, Cary, NC 27511, USA c of its mechanical simplicity, high dynamic range, low power requirements, large force capacity an attractive means of protecting civil infrastructure systems against severe earthquake and wind loading
L-H transition dynamics in fluid turbulence simulations with neoclassical force balance
Chôné, L. [Aix–Marseille Université, CNRS, PIIM UMR 7345, 13397 Marseille Cedex 20 (France); CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Beyer, P.; Fuhr, G.; Benkadda, S. [Aix–Marseille Université, CNRS, PIIM UMR 7345, 13397 Marseille Cedex 20 (France); Sarazin, Y.; Bourdelle, C. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)
2014-07-15T23:59:59.000Z
Spontaneous transport barrier generation at the edge of a magnetically confined plasma is reproduced in flux-driven three-dimensional fluid simulations of electrostatic turbulence. Here, the role on the radial electric field of collisional friction between trapped and passing particles is shown to be the key ingredient. Especially, accounting for the self-consistent and precise dependence of the friction term on the actual plasma temperature allows for the triggering of a transport barrier, provided that the input power exceeds some threshold. In addition, the barrier is found to experience quasi-periodic relaxation events, reminiscent of edge localised modes. These results put forward a possible key player, namely, neoclassical physics via radial force balance, for the low- to high-confinement regime transition observed in most of controlled fusion devices.
HFIR Plant Maintenance - August
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Multiple DeCART pin-resolved transport Neutronics + CFD Multiple LIME-coupled Star- CCM+ & DeCART pin-resolved transport + commercial computational fluid dynamics (CFD)...
Viggiano, Annarita [Department of Environmental Engineering and Physics, University of Basilicata, viale dell'Ateneo Lucano 10, 85100 Potenza (Italy)
2010-02-15T23:59:59.000Z
The influence of physical parameters and of flow patterns on the prediction of n-heptane ignition dynamic in transient reacting n-heptane jets, in high pressure environment under laminar conditions, has been explored by using different kinetic mechanisms. Some preliminary transient laminar flamelet computations have been performed, thus showing that the sensitivity of the ignition time to strain rate depends on the kinetic mechanism used. Therefore, the structure of the reacting jet, in particular the localization of ignition spots, is investigated. The results show that, if the initial temperature of the reacting mixture is out of the intermediate range (800-1000 K) towards lower values, the fluid dynamics has an essential role. In this case, the ignition delay time is almost insensitive to the specific kinetic mechanism adopted, conversely it is severely shortened by increasing the streamwise velocity. The burning spot is located in the core of fuel roll-up, where low values of scalar dissipation rate occur. Nevertheless, the most reactive mixture fraction conditions are well predicted by chemical kinetics, as they are in good agreement with those computed for the one-dimensional diffusion layer. When the initial temperature of fuel and air is increased in the intermediate range, ignition is strongly dependent on the kinetic mechanism used. In these cases, the choice of an accurate chemical scheme is fundamental in order to obtain reliable results. (author)
Under consideration for publication in J. Fluid Mech. 1 Three-dimensional vortex dynamics in
Pawlak, Geno
, the boundary layer can become centrifugally unstable (Honji 1981), leading to well-developed G¨ortler vortices dissipation and boundary layer dynamics. It is widely accepted that vortex shedding is a dominant pr in oscillatory flow separation M I G U E L C A N A L S AND G E N O P A W L A K Department of Ocean and Resources
The potential energy landscape and inherent dynamics of a hard-sphere fluid
Qingqing Ma; Richard M. Stratt
2014-08-13T23:59:59.000Z
Hard-sphere models exhibit many of the same kinds of supercooled-liquid behavior as more realistic models of liquids, but the highly non-analytic character of their potentials makes it a challenge to think of that behavior in potential-energy-landscape terms. We show here that it is possible to calculate an important topological property of hard-sphere landscapes, the geodesic pathways through those landscapes, and to do so without artificially coarse-graining or softening the potential. We show, moreover, that the rapid growth of the lengths of those pathways with increasing packing fraction quantitatively predicts the precipitous decline in diffusion constants in a glass-forming hard-sphere mixture model. The geodesic paths themselves can be considered as defining the intrinsic dynamics of hard spheres, so it is also revealing to find that they (and therefore the features of the underlying potential-energy landscape) correctly predict the occurrence of dynamic heterogeneity and non-zero values of the non-Gaussian parameter. The success of these landscape predictions for the dynamics of such a singular model emphasizes that there is more to potential energy landscapes than is revealed by looking at the minima and saddle points.
Dynamical Instability of Laminar Axisymmetric Flow of Perfect Fluid with Stratification
V. V. Zhuravlev; N. I. Shakura
2007-09-12T23:59:59.000Z
The instability of non-homoentropic axisymmetric flow of perfect fluid with respect to non-axisymmetric infinitesimal perturbations was investigated by numerical integration of hydrodynamical differential equations in two-dimensional approximation. The non-trivial influence of entropy gradient on unstable sound and surface gravity waves was revealed. In particular, both decrease and growth of entropy against the direction of effective gravitational acceleration $g_{eff}$ give rise to growing surface gravity modes which are stable with the same parameters in the case of homoentropic flow. At the same time increment of sound modes either grows monotonically while the rate of entropy decrease against $g_{eff}$ gets higher or vanishes at some values of positive and negative entropy gradient in the basic flow. The calculations have showed also that growing internal gravity modes appear only in the flow unstable to axisymmetric perturbations. At last, the analysis of boundary problem with free boundaries uncovered that's incorrect to set the entropy distribution according to polytropic law with polytropic index different from adiabatic value, since in this case perturbations don't satisfy the free boundary conditions.
Bianco, Ronald
2013-12-02T23:59:59.000Z
This thesis explores the effects of fluid flow on shear localization and frictional strength of fault gouge through the use of a coupled 2-phase (pore fluid-grain) Finite Difference-Discrete Element Numerical model. The model simulates slip...
Etele Molnar
2009-02-15T23:59:59.000Z
Focusing on the numerical aspects and accuracy we study a class of bulk viscosity driven expansion scenarios using the relativistic Navier-Stokes and truncated Israel-Stewart form of the equations of relativistic dissipative fluids in 1+1 dimensions. The numerical calculations of conservation and transport equations are performed using the numerical framework of flux corrected transport. We show that the results of the Israel-Stewart causal fluid dynamics are numerically much more stable and smoother than the results of the standard relativistic Navier-Stokes equations.
Al-Qahtani, Hussain M.
on the viscous nature of a fluid to provide damping. In addition to providing damping, other applications might be either a liquid or a gas. A fluid is said to be incompressible if the fluid's density remains Figure 7-2 Two tanks connected by a short pipe with a valve Since the relationship between the flow rate
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...
2010-01-01T23:59:59.000Z
three-dimensional (3D) boundary-layer flows has been focused on the disk; very little had been published © 2010 The Japan Society of Fluid Mechanics and IOP Publishing Ltd Printed in the UK 0169 implications for the fuel efficiency through increased noise and energy dissipation, and for projectile
CFD MODELING AND ANALYSIS FOR A-AREA AND H-AREA COOLING TOWERS
Lee, S.; Garrett, A.; Bollinger, J.
2009-09-02T23:59:59.000Z
Mechanical draft cooling towers are designed to cool process water via sensible and latent heat transfer to air. Heat and mass transfer take place simultaneously. Heat is transferred as sensible heat due to the temperature difference between liquid and gas phases, and as the latent heat of the water as it evaporates. Mass of water vapor is transferred due to the difference between the vapor pressure at the air-liquid interface and the partial pressure of water vapor in the bulk of the air. Equations to govern these phenomena are discussed here. The governing equations are solved by taking a computational fluid dynamics (CFD) approach. The purpose of the work is to develop a three-dimensional CFD model to evaluate the flow patterns inside the cooling tower cell driven by cooling fan and wind, considering the cooling fans to be on or off. Two types of the cooling towers are considered here. One is cross-flow type cooling tower located in A-Area, and the other is counterflow type cooling tower located in H-Area. The cooling tower located in A-Area is mechanical draft cooling tower (MDCT) consisting of four compartment cells as shown in Fig. 1. It is 13.7m wide, 36.8m long, and 9.4m high. Each cell has its own cooling fan and shroud without any flow communications between two adjacent cells. There are water distribution decks on both sides of the fan shroud. The deck floor has an array of about 25mm size holes through which water droplet falls into the cell region cooled by the ambient air driven by fan and wind, and it is eventually collected in basin area. As shown in Fig. 1, about 0.15-m thick drift eliminator allows ambient air to be humidified through the evaporative cooling process without entrainment of water droplets into the shroud exit. The H-Area cooling tower is about 7.3 m wide, 29.3 m long, and 9.0 m high. Each cell has its own cooling fan and shroud, but each of two corner cells has two panels to shield wind at the bottom of the cells. There is some degree of flow communications between adjacent cells through the 9-in gap at the bottom of the tower cells as shown in Fig. 2. Detailed geometrical dimensions for the H-Area tower configurations are presented in the figure. The model was benchmarked and verified against off-site and on-site test results. The verified model was applied to the investigation of cooling fan and wind effects on water cooling in cells when fans are off and on. This report will discuss the modeling and test results.
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.
Fluid Flow Modeling in Fractures
Sarkar, Sudipta
2004-01-01T23:59:59.000Z
In this paper we study fluid flow in fractures using numerical simulation and address the challenging issue of hydraulic property characterization in fractures. The methodology is based on Computational Fluid Dynamics, ...
A Molecular Dynamics Simulation of the Turbulent Couette Minimal Flow Unit
Smith, E R
2015-01-01T23:59:59.000Z
A molecular dynamics (MD) simulation of planar Couette flow is presented for the minimal channel in which turbulence structures can be sustained. Evolution over a single breakdown and regeneration cycle is compared to computational fluid dynamics (CFD) simulations. Qualitative similar structures are observed and turbulent statistics show excellent quantitative agreement. The molecular scale law of the wall is presented in which stick-slip molecular wall-fluid interactions replace the no-slip conditions. The impact of grid resolution is explored and the observed structures are seen to be dependant on averaging time and length scales. The kinetic energy spectra show a range of scales are present in the molecular system and that spectral content is dependent on the grid resolution employed. The subgrid velocity of the molecules is compared to spatial averaged velocity using joint probability density functions. Molecular trajectories, diffusions and Lagrangian statistics are presented. The importance of sub-grid ...
APPLICATIONS OF CFD METHOD TO GAS MIXING ANALYSIS IN A LARGE-SCALED TANK
Lee, S; Richard Dimenna, R
2007-03-19T23:59:59.000Z
The computational fluid dynamics (CFD) modeling technique was applied to the estimation of maximum benzene concentration for the vapor space inside a large-scaled and high-level radioactive waste tank at Savannah River site (SRS). The objective of the work was to perform the calculations for the benzene mixing behavior in the vapor space of Tank 48 and its impact on the local concentration of benzene. The calculations were used to evaluate the degree to which purge air mixes with benzene evolving from the liquid surface and its ability to prevent an unacceptable concentration of benzene from forming. The analysis was focused on changing the tank operating conditions to establish internal recirculation and changing the benzene evolution rate from the liquid surface. The model used a three-dimensional momentum coupled with multi-species transport. The calculations included potential operating conditions for air inlet and exhaust flows, recirculation flow rate, and benzene evolution rate with prototypic tank geometry. The flow conditions are assumed to be fully turbulent since Reynolds numbers for typical operating conditions are in the range of 20,000 to 70,000 based on the inlet conditions of the air purge system. A standard two-equation turbulence model was used. The modeling results for the typical gas mixing problems available in the literature were compared and verified through comparisons with the test results. The benchmarking results showed that the predictions are in good agreement with the analytical solutions and literature data. Additional sensitivity calculations included a reduced benzene evolution rate, reduced air inlet and exhaust flow, and forced internal recirculation. The modeling results showed that the vapor space was fairly well mixed and that benzene concentrations were relatively low when forced recirculation and 72 cfm ventilation air through the tank boundary were imposed. For the same 72 cfm air inlet flow but without forced recirculation, the heavier benzene gas was stratified. The results demonstrated that benzene concentrations were relatively low for typical operating configurations and conditions. Detailed results and the cases considered in the calculations will be discussed here.
Apte, Sourabh V.
Open Journal of Fluid Dynamics, 2012, 2, 35-43 doi:10.4236/ojfd.2012.22004 Published Online June; accepted May 25, 2012 ABSTRACT In many applications, a moving fluid carries a suspension of droplets of a second phase which may change in size due to evaporation or condensation. Examples include liquid fuel
CFD Modeling of Methane Production from Hydrate-Bearing Reservoir
Gamwo, I.K.; Myshakin, E.M.; Warzinski, R.P.
2007-04-01T23:59:59.000Z
Methane hydrate is being examined as a next-generation energy resource to replace oil and natural gas. The U.S. Geological Survey estimates that methane hydrate may contain more organic carbon the the world's coal, oil, and natural gas combined. To assist in developing this unfamiliar resource, the National Energy Technology Laboratory has undertaken intensive research in understanding the fate of methane hydrate in geological reservoirs. This presentation reports preliminary computational fluid dynamics predictions of methane production from a subsurface reservoir.
Under consideration for publication in J. Fluid Mech. 1 Shape dynamics and scaling laws for a body
dissolving in fluid flow Jinzi Mac Huang1, M. Nicholas J. Moore1,2, Leif Ristroph1 1 Applied Math Lab November 2014) While fluid flows are known to promote dissolution of materials, such processes are poorly problem through experiments in which hard candy bodies dissolve in laminar, high-speed water flows. We
Haghshenas, Arash
2013-04-24T23:59:59.000Z
The worst scenario of drilling operation is blowout which is uncontrolled flow of formation fluid into the wellbore. Blowouts result in environmental damage with potential risk of injuries and fatalities. Although not all blowouts result in disaster...
Edison, John R.; Monson, Peter A. [Department of Chemical Engineering, University of Massachusetts, Amherst, Massachusetts 01003-9303 (United States)
2014-07-14T23:59:59.000Z
Recently we have developed a dynamic mean field theory (DMFT) for lattice gas models of fluids in porous materials [P. A. Monson, J. Chem. Phys. 128(8), 084701 (2008)]. The theory can be used to describe the relaxation processes in the approach to equilibrium or metastable states for fluids in pores and is especially useful for studying system exhibiting adsorption/desorption hysteresis. In this paper we discuss the extension of the theory to higher order by means of the path probability method (PPM) of Kikuchi and co-workers. We show that this leads to a treatment of the dynamics that is consistent with thermodynamics coming from the Bethe-Peierls or Quasi-Chemical approximation for the equilibrium or metastable equilibrium states of the lattice model. We compare the results from the PPM with those from DMFT and from dynamic Monte Carlo simulations. We find that the predictions from PPM are qualitatively similar to those from DMFT but give somewhat improved quantitative accuracy, in part due to the superior treatment of the underlying thermodynamics. This comes at the cost of greater computational expense associated with the larger number of equations that must be solved.
CFD in support of development and optimization of the MIT LEU fuel element design
Diaconeasa, Mihai Aurelian
2014-01-01T23:59:59.000Z
The effect of lateral power distribution of the MITR LEU fuel design was analyzed using Computational Fluid Dynamics. Coupled conduction and convective heat transfer were modeled for uniform and non-uniform lateral power ...
Gnie mcanique Using the NSMB CFD solver to Compute Dynamic
Lausanne, Ecole Polytechnique Fédérale de
Sylvain Gallay Supervisors Dr. Mark Sawley Acknowledgements Dr. Mark Sawley Dr Jan B. Vos Dr. Mark Sawley
Granular Dynamics in Pebble Bed Reactor Cores
Laufer, Michael Robert
2013-01-01T23:59:59.000Z
a simulant fluid to match the dynamics of fuel pebbles andfuel pebbles through reactor cores with and without coupled fluid
Optimization of a Two-Fluid Hydrodynamic Model of Churn-Turbulent Flow
Donna Post Guillen
2009-07-01T23:59:59.000Z
A hydrodynamic model of two-phase, churn-turbulent flows is being developed using the computational multiphase fluid dynamics (CMFD) code, NPHASE-CMFD. The numerical solutions obtained by this model are compared with experimental data obtained at the TOPFLOW facility of the Institute of Safety Research at the Forschungszentrum Dresden-Rossendorf. The TOPFLOW data is a high quality experimental database of upward, co-current air-water flows in a vertical pipe suitable for validation of computational fluid dynamics (CFD) codes. A five-field CMFD model was developed for the continuous liquid phase and four bubble size groups using mechanistic closure models for the ensemble-averaged Navier-Stokes equations. Mechanistic models for the drag and non-drag interfacial forces are implemented to include the governing physics to describe the hydrodynamic forces controlling the gas distribution. The closure models provide the functional form of the interfacial forces, with user defined coefficients to adjust the force magnitude. An optimization strategy was devised for these coefficients using commercial design optimization software. This paper demonstrates an approach to optimizing CMFD model parameters using a design optimization approach. Computed radial void fraction profiles predicted by the NPHASE-CMFD code are compared to experimental data for four bubble size groups.
Feng, James J.
for polymer solutions -- being stretched and oriented by flow and deformation. In technological applications of the components. Other examples of complex fluid mixtures include thermoplastic foam and oil-water emulsions of the interfaces between the components. With the advent of micro-engineering and nano-technology
CHARACTERIZATION OF MACAQUE PULMONARY FLUID PROTEOME DURING MONKEYPOX...
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CHARACTERIZATION OF MACAQUE PULMONARY FLUID PROTEOME DURING MONKEYPOX INFECTION: DYNAMICS OF HOST RESPONSE. CHARACTERIZATION OF MACAQUE PULMONARY FLUID PROTEOME DURING MONKEYPOX...
Ghobadi, Ahmadreza F.; Elliott, J. Richard, E-mail: elliot1@uakron.edu [Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325 (United States)
2014-07-14T23:59:59.000Z
In this work, a new classical density functional theory is developed for group-contribution equations of state (EOS). Details of implementation are demonstrated for the recently-developed SAFT-? WCA EOS and selective applications are studied for confined fluids and vapor-liquid interfaces. The acronym WCA (Weeks-Chandler-Andersen) refers to the characterization of the reference part of the third-order thermodynamic perturbation theory applied in formulating the EOS. SAFT-? refers to the particular form of “statistical associating fluid theory” that is applied to the fused-sphere, heteronuclear, united-atom molecular models of interest. For the monomer term, the modified fundamental measure theory is extended to WCA-spheres. A new chain functional is also introduced for fused and soft heteronuclear chains. The attractive interactions are taken into account by considering the structure of the fluid, thus elevating the theory beyond the mean field approximation. The fluctuations of energy are also included via a non-local third-order perturbation theory. The theory includes resolution of the density profiles of individual groups such as CH{sub 2} and CH{sub 3} and satisfies stoichiometric constraints for the density profiles. New molecular simulations are conducted to demonstrate the accuracy of each Helmholtz free energy contribution in reproducing the microstructure of inhomogeneous systems at the united-atom level of coarse graining. At each stage, comparisons are made to assess where the present theory stands relative to the current state of the art for studying inhomogeneous fluids. Overall, it is shown that the characteristic features of real molecular fluids are captured both qualitatively and quantitatively. For example, the average pore density deviates ?2% from simulation data for attractive pentadecane in a 2-nm slit pore. Another example is the surface tension of ethane/heptane mixture, which deviates ?1% from simulation data while the theory reproduces the excess accumulation of ethane at the interface.
Fluid&ParticulateSystems 424514/2010
Zevenhoven, Ron
cake solids mass/m2, w 3. Ruth equation using dw = (1-)solid dx fluidL p Ku solidK )1( 1 resistance, , with cake porosity : velocity, u layer thickness, L pressure drop, p dynamic viscosity, fluid Finland februari 2014 Unit w: kg/m2 Fluid&ParticulateSystems 424514/2010 Fluid&ParticulateSystems ÅA424514
Validation of CFD Simulations for Natural Ventilation , Camille Allocca1
Chen, Qingyan "Yan"
ventilation is a very typical unsteady flow problem, the study of natural ventilation by RANS may need1 Validation of CFD Simulations for Natural Ventilation Yi Jiang1 , Camille Allocca1 , and Qingyan ventilation, which may provide occupants with good indoor air quality and a high level of thermal comfort
Thermal hydraulic simulations, error estimation and parameter sensitivity studies in Drekar::CFD
Smith, Thomas Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Shadid, John N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pawlowski, Roger P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cyr, Eric C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wildey, Timothy Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2014-01-01T23:59:59.000Z
This report describes work directed towards completion of the Thermal Hydraulics Methods (THM) CFD Level 3 Milestone THM.CFD.P7.05 for the Consortium for Advanced Simulation of Light Water Reactors (CASL) Nuclear Hub effort. The focus of this milestone was to demonstrate the thermal hydraulics and adjoint based error estimation and parameter sensitivity capabilities in the CFD code called Drekar::CFD. This milestone builds upon the capabilities demonstrated in three earlier milestones; THM.CFD.P4.02 [12], completed March, 31, 2012, THM.CFD.P5.01 [15] completed June 30, 2012 and THM.CFD.P5.01 [11] completed on October 31, 2012.
Correa Castro, Juan
2011-08-08T23:59:59.000Z
Hill Committee Member, Yuefeng Sun Head of Department, Stephen A. Holditch May 2011 Major Subject: Petroleum Engineering iii ABSTRACT Evaluation and Effect of Fracturing Fluids on Fracture Conductivity in Tight Gas Reservoirs Using... were used (150 ?F and 250 ?F) (Much and Penny, 1987). The standard procedure was documented in API-61 (API, 1989) where proppant is loaded at a specific concentration (e.g. 2 lb/ft2) between two core slabs (Ohio Sandstone) in an API conductivity cell...
Goel, Piyush
2010-10-12T23:59:59.000Z
A Web-server farm is a specialized facility designed specifically for housing Web servers catering to one or more Internet facing Web sites. In this dissertation, stochastic dynamic programming technique is used to obtain the optimal admission...
Quantifying the stimuli of photorheological fluids
Bates, Sarah Woodring
2010-01-01T23:59:59.000Z
We develop a model to predict the dynamics of photorheological fluids and, more generally, photoresponsive fluids for monochromatic and polychromatic light sources. Derived from first principles, the model relates the ...
An Investigation of Surface and Crown Fire Dynamics in Shrub Fuels
Lozano, Jesse Sandoval
2011-01-01T23:59:59.000Z
fluid dynamic environment between two adjacent crown fuels andadjacent crown fuel matrices and to study any fluid dynamicbetween crown fuel matrices, and to study any fluid dynamic
Benitz, M. A.; Schmidt, D. P.; Lackner, M. A.; Stewart, G. M.; Jonkman, J.; Robertson, A.
2014-09-01T23:59:59.000Z
Hydrodynamic loads on the platforms of floating offshore wind turbines are often predicted with computer-aided engineering tools that employ Morison's equation and/or potential-flow theory. This work compares results from one such tool, FAST, NREL's wind turbine computer-aided engineering tool, and the computational fluid dynamics package, OpenFOAM, for the OC4-DeepCwind semi-submersible analyzed in the International Energy Agency Wind Task 30 project. Load predictions from HydroDyn, the offshore hydrodynamics module of FAST, are compared with high-fidelity results from OpenFOAM. HydroDyn uses a combination of Morison's equations and potential flow to predict the hydrodynamic forces on the structure. The implications of the assumptions in HydroDyn are evaluated based on this code-to-code comparison.
Under consideration for publication in J. Fluid Mech. 1 Tear Film Dynamics on an Eye-shaped
Bacuta, Constantin
-0808, USA 3 College of Optometry, The Ohio State University, Columbus OH 43218, USA (Received 1 August 2009) We model the dynamics of the human tear film during relaxation (after a blink) us- ing lubrication features seen in one-dimensional simulations and capture some experimental ob- servations of tear film
FRACTURING FLUID CHARACTERIZATION FACILITY
Subhash Shah
2000-08-01T23:59:59.000Z
Hydraulic fracturing technology has been successfully applied for well stimulation of low and high permeability reservoirs for numerous years. Treatment optimization and improved economics have always been the key to the success and it is more so when the reservoirs under consideration are marginal. Fluids are widely used for the stimulation of wells. The Fracturing Fluid Characterization Facility (FFCF) has been established to provide the accurate prediction of the behavior of complex fracturing fluids under downhole conditions. The primary focus of the facility is to provide valuable insight into the various mechanisms that govern the flow of fracturing fluids and slurries through hydraulically created fractures. During the time between September 30, 1992, and March 31, 2000, the research efforts were devoted to the areas of fluid rheology, proppant transport, proppant flowback, dynamic fluid loss, perforation pressure losses, and frictional pressure losses. In this regard, a unique above-the-ground fracture simulator was designed and constructed at the FFCF, labeled ''The High Pressure Simulator'' (HPS). The FFCF is now available to industry for characterizing and understanding the behavior of complex fluid systems. To better reflect and encompass the broad spectrum of the petroleum industry, the FFCF now operates under a new name of ''The Well Construction Technology Center'' (WCTC). This report documents the summary of the activities performed during 1992-2000 at the FFCF.
W. Schmidt; J. C. Niemeyer; W. Hillebrandt; F. K. Roepke
2006-01-23T23:59:59.000Z
The dynamics of the explosive burning process is highly sensitive to the flame speed model in numerical simulations of type Ia supernovae. Based upon the hypothesis that the effective flame speed is determined by the unresolved turbulent velocity fluctuations, we employ a new subgrid scale model which includes a localised treatment of the energy transfer through the turbulence cascade in combination with semi-statistical closures for the dissipation and non-local transport of turbulence energy. In addition, subgrid scale buoyancy effects are included. In the limit of negligible energy transfer and transport, the dynamical model reduces to the Sharp-Wheeler relation. According to our findings, the Sharp-Wheeler relation is insuffcient to account for the complicated turbulent dynamics of flames in thermonuclear supernovae. The application of a co-moving grid technique enables us to achieve very high spatial resolution in the burning region. Turbulence is produced mostly at the flame surface and in the interior ash regions. Consequently, there is a pronounced anisotropy in the vicinity of the flame fronts. The localised subgrid scale model predicts significantly enhanced energy generation and less unburnt carbon and oxygen at low velocities compared to earlier simulations.
Supersymmetric Fluid Mechanics
R. Jackiw; A. P. Polychronakos
2000-07-17T23:59:59.000Z
When anticommuting Grassmann variables are introduced into a fluid dynamical model with irrotational velocity and no vorticity, the velocity acquires a nonvanishing curl and the resultant vorticity is described by Gaussian potentials formed from the Grassmann variables. Upon adding a further specific interaction with the Grassmann degrees of freedom, the model becomes supersymmetric.
Single-cell dynamics of mammalian gene regulation
Kolnik, Martin
2012-01-01T23:59:59.000Z
Given the laminar nature of fluid flow on the microscale,laminar flow regime that is characteristic of fluid dynamics
Characterizing Microbial Community and Geochemical Dynamics at...
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Microbial Community and Geochemical Dynamics at Hydrothermal Vents Using Osmotically Driven Continuous Fluid Characterizing Microbial Community and Geochemical Dynamics at...
Mcvay, Kyle
2014-08-08T23:59:59.000Z
parameters which include: the scaled geometry from INL, fabrication process limitations, can supply sufficient heat to the modeled core for testing, a heat sink sufficient to remove the heat input, and a system that allows for sufficient data acquisition... velocity profile following a PCC accident scenario 7 Figure 2-2: VHTR temperature profile following a PCC accident scenario Tung and Johnson working with INL published a study in 2011 of CFD analysis for a 1/12th sector of a heated column...
CFD Modeling for Lost Foam White Side | Department of Energy
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 Data Center Home Page on Delicious RankShale_Gas.pdfService on the TargetFY12Environmentto WholeII -Langston 1TableCERC-BEEChemistry |CFD
Sandia Energy - CFD-Populated Empirical Turbine Wake Model
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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:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5(Million Cubic Feet) Oregon (Including Vehicle Fuel) (Million CubicRefiners SwitchBenefitsBeam LineSandian as Permalink GalleryBob BiefeldCFD-Populated
Hajdukiewicz, M.; Keane, M.; O'Flynn, B.; O'Grady, W.
2010-01-01T23:59:59.000Z
controlled internal environments. In this research a CFD model of the internal environment of an office space will be developed. The CFD model will then be calibrated using real data taken from a well-positioned wireless sensor network and weather station...
Aalborg Universitet CFD modeling and experience of waste-to-energy plant burning waste wood
Yin, Chungen
Aalborg Universitet CFD modeling and experience of waste-to-energy plant burning waste wood Rajh, B-to- energy plant burning waste wood. In Proceedings of the 14th International Waste Management and Landfill by CISA Publisher, Italy CFD MODELING AND EXPERIENCE OF WASTE-TO-ENERGY PLANT BURNING WASTE WOOD B. RAJH
Assessment of low-order theories for analysis and design of shrouded wind turbines using CFD
Alonso, Juan J.
Assessment of low-order theories for analysis and design of shrouded wind turbines using CFD Aniket of a shroud around the rotor of a wind turbine has been known to augment the airflow through the rotor plane the validity of several simple theories which attempt to extend Betz theory to shrouded turbines. Two CFD
Sandia Energy - High-Fidelity Hydrostructural Analysis of Ocean...
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(ORPC's) TidGen turbine using the computational fluids dynamics (CFD) tool Star CCM+ and the structural-dynamics modeling capability in the Abaqus finite-element...
Kelley, N.D.
1993-11-01T23:59:59.000Z
We have recently shown that the alternating load fatigue distributions measured at several locations on a wind turbine operating in a turbulent flow can be described by a mixture of at least three parametric statistical models. The rainflow cycle counting of the horizontal and vertical inflow components results in a similar mixture describing the cyclic content of the wind. We believe such a description highlights the degree of non-Gaussian characteristics of the flow. We present evidence that the severity of the low-cycle, high-amplitude alternating stress loads seen by wind turbine components are a direct consequence of the degree of departure from normality in the inflow. We have examined the details of the turbulent inflow associated with series large loading events that took place on two adjacent wind turbines installed in a large wind park in San Gorgonio Pass, California. In this paper, we describe what we believe to be the agents in the flow that induced such events. We also discuss the atmospheric mechanisms that influence the low-cycle, high-amplitude range loading seen by a number of critical wind turbine components. We further present results that can be used to scale the specific distribution shape as functions of measured inflow fluid dynamics parameters.
Prediction of Room Air Diffusion for Reduced Diffuser Flow Rates
Gangisetti, Kavita
2011-02-22T23:59:59.000Z
With the ever-increasing availability of high performance computing facilities, numerical simulation through Computational Fluid Dynamics (CFD) is increasingly used to predict the room air distribution. CFD is becoming an important design...
IEEE Paper Template in A4 (V1)
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A high-fidelity computational fluid dynamics (CFD) model was also developed using STAR-CCM+ 7. This CFD model solves the 3D steady Reynolds-averaged Navier-Stokes equations...
Geophysical Fluid Dynamics Laboratory Review
;4 · When internal diffusion is low, winds end up being dominant source of energy Toggweiler et al, 1993 #12;5 · When internal diffusion is low, winds end up being dominant source of energy · Shifts in winds in Brazil BasinWhile ocean is turbulent both horizontally and vertically.... Diffusivities associated
Fluid Dynamics and Solid Mechanics
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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:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article)41clothThe Bonneville Power AdministrationHawaiiEnergyFlorida July 9,Department ofFlooded First StreetperFlu shots available3
Anastasia Gribik; Doona Guillen, PhD; Daniel Ginosar, PhD
2008-09-01T23:59:59.000Z
Currently multi-tubular fixed bed reactors, fluidized bed reactors, and slurry bubble column reactors (SBCRs) are used in commercial Fischer Tropsch (FT) synthesis. There are a number of advantages of the SBCR compared to fixed and fluidized bed reactors. The main advantage of the SBCR is that temperature control and heat recovery are more easily achieved. The SBCR is a multiphase chemical reactor where a synthesis gas, comprised mainly of H2 and CO, is bubbled through a liquid hydrocarbon wax containing solid catalyst particles to produce specialty chemicals, lubricants, or fuels. The FT synthesis reaction is the polymerization of methylene groups [-(CH2)-] forming mainly linear alkanes and alkenes, ranging from methane to high molecular weight waxes. The Idaho National Laboratory is developing a computational multiphase fluid dynamics (CMFD) model of the FT process in a SBCR. This paper discusses the incorporation of absorption and reaction kinetics into the current hydrodynamic model. A phased approach for incorporation of the reaction kinetics into a CMFD model is presented here. Initially, a simple kinetic model is coupled to the hydrodynamic model, with increasing levels of complexity added in stages. The first phase of the model includes incorporation of the absorption of gas species from both large and small bubbles into the bulk liquid phase. The driving force for the gas across the gas liquid interface into the bulk liquid is dependent upon the interfacial gas concentration in both small and large bubbles. However, because it is difficult to measure the concentration at the gas-liquid interface, coefficients for convective mass transfer have been developed for the overall driving force between the bulk concentrations in the gas and liquid phases. It is assumed that there are no temperature effects from mass transfer of the gas phases to the bulk liquid phase, since there are only small amounts of dissolved gas in the liquid phase. The product from the incorporation of absorption is the steady state concentration profile of the absorbed gas species in the bulk liquid phase. The second phase of the model incorporates a simplified macrokinetic model to the mass balance equation in the CMFD code. Initially, the model assumes that the catalyst particles are sufficiently small such that external and internal mass and heat transfer are not rate limiting. The model is developed utilizing the macrokinetic rate expression developed by Yates and Satterfield (1991). Initially, the model assumes that the only species formed other than water in the FT reaction is C27H56. Change in moles of the reacting species and the resulting temperature of the catalyst and fluid phases is solved simultaneously. The macrokinetic model is solved in conjunction with the species transport equations in a separate module which is incorporated into the CMFD code.
CFD based rotordynamic coefficients for labyrinth seals and impeller leakage paths
Bhattacharya, Avijit
1997-01-01T23:59:59.000Z
accurately using simple flow model like bulk flow. CFD approach is employed since it can accurately predict and capture recirculating zones using proper mesh distribution. The Impeller Leakage paths and Labyrinth Seals, typically, have a recirculation zone...
Deng, T.; Zhang, Q.; Zhang, G.; Yuan, H.
2006-01-01T23:59:59.000Z
The Hunan International Exhibition Center (HIEC) is a large space building. A stratified air-conditioning system on the second floor of the building has been adopted. Due to some problems with the air supply jet diffuser, CFD simulations were...
Comparative Analysis of CFD ?P vs. Measured ?P for Compressed Flexible Ducts
Ugursal, A.; Culp, C.H.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Comparative Analysis of CFD [Delta]P vs. Measured [Delta]P for Compressed Flexible Ducts Ugursal, Ahmet;Culp, Charles ASHRAE Transactions; 2007...
Deng, T.; Zhang, Q.; Zhang, G.; Yuan, H.
2006-01-01T23:59:59.000Z
The Hunan International Exhibition Center (HIEC) is a large space building. A stratified air-conditioning system on the second floor of the building has been adopted. Due to some problems with the air supply jet diffuser, CFD simulations were...
An Eulerian CFD Model and X-ray Radiography for Coupled Nozzle...
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Model and X-ray Radiography for Coupled Nozzle Flow and Spray in Internal Combustion Engines Title An Eulerian CFD Model and X-ray Radiography for Coupled Nozzle Flow and Spray...
Relativistic viscoelastic fluid mechanics
Masafumi Fukuma; Yuho Sakatani
2011-09-01T23:59:59.000Z
A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by the Navier-Stokes equations, so that acausal problems intrinsic to relativistic Navier-Stokes fluids are significantly remedied. We in particular show that the wave equations for the propagation of disturbance around a hydrostatic equilibrium in Minkowski spacetime become symmetric hyperbolic for some range of parameters, so that the model is free of acausality problems. This observation suggests that the relativistic viscoelastic model with such parameters can be regarded as a causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting parameters to various values, this theory can treat a wide variety of materials including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus we expect the theory to be the most universal description of single-component relativistic continuum materials. We also show that the presence of strains and the corresponding change in temperature are naturally unified through the Tolman law in a generally covariant description of continuum mechanics.
CFD Analysis of Nuclear Fuel Bundles and Spacer Grids for PWR Reactors
Capone, Luigi
2012-10-19T23:59:59.000Z
. Therefore, supports are needed for structural reasons. Also, fuel rods have to be kept in the design geometrical arrangement to ensure optimum heat transfer conditions. The fuel assemblies are equipped with several spacer grids and sometimes... flow is generated by MV that generates secondary flow and increase of the flow splitting between different sub-channels 5 increasing the heat transfer between the fuel rods and the primary coolant). From a fluid dynamics point of view the MV can...
Simulating Fluids Exhibiting Microstructure
Title: Simulating Fluids Exhibiting Microstructure Speaker: Noel J. Walkington, ... fluids containing elastic particles, and polymer fluids, all exhibit non-trivial ...
The Effects of Geometry on Flexible Duct CFD Simulations
Ugursal, A.; Culp, C.
Flexible ducts have been widely used in the building industry due to low cost and ease of installation. These ducts can be installed in a wide range of configurations, which creates a challenge for pressure loss calculations. Computational fluid...
DECOUPLED TIME STEPPING METHODS FOR FLUID-FLUID INTERACTION
Kasman, Alex
-fluid interaction, atmosphere-ocean, implicit-explicit method. 1. Introduction. The dynamic core in atmosphere-ocean to the coupled system using only (uncoupled) atmosphere and ocean solves, (see e.g. [4, 6, 17, 18, 19 their shared interface I by a rigid-lid coupling condition, i.e. no penetration and a slip with friction
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:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article) |govInstrumentsmfrirt DocumentationSitesWeather6Environmental SecurityExtra-LargeBauerWorldwideFascinating Fluids
Mechanical Engineering ME 3720 FLUID MECHANICS
Panchagnula, Mahesh
. Fundamentals of fluid flow; fluid statics; systems, and control volumes; continuity, momentum and energy physical model results to prototype 10. Use Moody chart to calculate friction losses in pipe flows 11 equations; dynamic similitude; One-dimensional compressible flow. The objective(s) of this course is (are
Prof. Dr.-Ing. Heinz Pitsch Templergraben 64
Peters, Norbert
CFD (Computational Fluid Dynamics) Simulationen unterstützen. Im Rahmen des Exzellenzclusters ,,Tailor-made Fuels from Biomass" wird am Institut für Technische Verbrennung die chemische Kinetik von alternativen
Mobile Ice Nucleus Spectrometer
Kulkarni, Gourihar R.; Kok, G. L.
2012-05-07T23:59:59.000Z
This first year report presents results from a computational fluid dynamics (CFD) study to assess the flow and temperature profiles within the mobile ice nucleus spectrometer.
Quantifying Uncertainty in Computer Predictions | netl.doe.gov
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
initiated work on the verification, validation and uncertainty quantification of multiphase computational fluid dynamics (CFD) models that underpin the simulation of several...
January 2013 Labnotes | netl.doe.gov
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
cleanup and carbon management equipment. At NETL, scientists have developed in-house multiphase computational fluid dynamic (CFD) model MFIX (Multiphase Flow with Interphase...
HOW MULTIDISCIPLINARY SCIENTIFIC RESEARCH MAY HELP BREAK THE SAILING SPEED RECORD
Fua, Pascal
Coupled fluid/structure dynamic simulation Experimental validation Hydrodynamics: 3D CFD simulation of the foils Optimization / Cavitation limit Experimental validation Materials: Safety of operation Weight
Wai, Chien M. (Moscow, ID); Laintz, Kenneth E. (Los Alamos, NM)
1999-01-01T23:59:59.000Z
A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated .beta.-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated .beta.-diketone and a trialkyl phosphate, or a fluorinated .beta.-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated .beta.-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.
Faybishenko, B.; Doughty, C.; Geller, J. [and others
1998-07-01T23:59:59.000Z
Understanding subsurface flow and transport processes is critical for effective assessment, decision-making, and remediation activities for contaminated sites. However, for fluid flow and contaminant transport through fractured vadose zones, traditional hydrogeological approaches are often found to be inadequate. In this project, the authors examine flow and transport through a fractured vadose zone as a deterministic chaotic dynamical process, and develop a model of it in these terms. Initially, the authors examine separately the geometric model of fractured rock and the flow dynamics model needed to describe chaotic behavior. Ultimately they will put the geometry and flow dynamics together to develop a chaotic-dynamical model of flow and transport in a fractured vadose zone. They investigate water flow and contaminant transport on several scales, ranging from small-scale laboratory experiments in fracture replicas and fractured cores, to field experiments conducted in a single exposed fracture at a basalt outcrop, and finally to a ponded infiltration test using a pond of 7 by 8 m. In the field experiments, they measure the time-variation of water flux, moisture content, and hydraulic head at various locations, as well as the total inflow rate to the subsurface. Such variations reflect the changes in the geometry and physics of water flow that display chaotic behavior, which they try to reconstruct using the data obtained. In the analysis of experimental data, a chaotic model can be used to predict the long-term bounds on fluid flow and transport behavior, known as the attractor of the system, and to examine the limits of short-term predictability within these bounds. This approach is especially well suited to the need for short-term predictions to support remediation decisions and long-term bounding studies. View-graphs from ten presentations made at the annual meeting held December 3--4, 1997 are included in an appendix to this report.
Standardization of Thermo-Fluid Modeling in Modelica.Fluid
Franke, Rudiger; Casella, Francesco; Sielemann, Michael; Proelss, Katrin; Otter, Martin; Wetter, Michael
2009-09-01T23:59:59.000Z
This article discusses the Modelica.Fluid library that has been included in the Modelica Standard Library 3.1. Modelica.Fluid provides interfaces and basic components for the device-oriented modeling of onedimensional thermo-fluid flow in networks containing vessels, pipes, fluid machines, valves and fittings. A unique feature of Modelica.Fluid is that the component equations and the media models as well as pressure loss and heat transfer correlations are decoupled from each other. All components are implemented such that they can be used for media from the Modelica.Media library. This means that an incompressible or compressible medium, a single or a multiple substance medium with one or more phases might be used with one and the same model as long as the modeling assumptions made hold. Furthermore, trace substances are supported. Modeling assumptions can be configured globally in an outer System object. This covers in particular the initialization, uni- or bi-directional flow, and dynamic or steady-state formulation of mass, energy, and momentum balance. All assumptions can be locally refined for every component. While Modelica.Fluid contains a reasonable set of component models, the goal of the library is not to provide a comprehensive set of models, but rather to provide interfaces and best practices for the treatment of issues such as connector design and implementation of energy, mass and momentum balances. Applications from various domains are presented.
Eça, L. [Instituto Superior Técnico, Department of Mechanical Engineering, Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Hoekstra, M. [Maritime Research Institute Netherlands, PO Box 28 6700 AA, Wageningen (Netherlands)
2014-04-01T23:59:59.000Z
This paper offers a procedure for the estimation of the numerical uncertainty of any integral or local flow quantity as a result of a fluid flow computation; the procedure requires solutions on systematically refined grids. The error is estimated with power series expansions as a function of the typical cell size. These expansions, of which four types are used, are fitted to the data in the least-squares sense. The selection of the best error estimate is based on the standard deviation of the fits. The error estimate is converted into an uncertainty with a safety factor that depends on the observed order of grid convergence and on the standard deviation of the fit. For well-behaved data sets, i.e. monotonic convergence with the expected observed order of grid convergence and no scatter in the data, the method reduces to the well known Grid Convergence Index. Examples of application of the procedure are included. - Highlights: • Estimation of the numerical uncertainty of any integral or local flow quantity. • Least squares fits to power series expansions to handle noisy data. • Excellent results obtained for manufactured solutions. • Consistent results obtained for practical CFD calculations. • Reduces to the well known Grid Convergence Index for well-behaved data sets.
CFD analyses of natural circulation in the air-cooled reactor cavity cooling system
Hu, R. [Nuclear Engineering Division, Argonne National Laboratory, Argonne IL (United States); Pointer, W. D. [Reactor and Nuclear Systems Division, Oak Ridge National Laboratory, Oak Ridge TN (United States)
2013-07-01T23:59:59.000Z
The Natural Convection Shutdown Heat Removal Test Facility (NSTF) is currently being built at Argonne National Laboratory, to evaluate the feasibility of the passive Reactor Cavity Cooling System (RCCS) for Next Generation Nuclear Plant (NGNP). CFD simulations have been applied to evaluate the NSTF and NGNP RCCS designs. However, previous simulations found that convergence was very difficult to achieve in simulating the complex natural circulation. To resolve the convergence issue and increase the confidence of the CFD simulation results, additional CFD simulations were conducted using a more detailed mesh and a different solution scheme. It is found that, with the use of coupled flow and coupled energy models, the convergence can be greatly improved. Furthermore, the effects of convection in the cavity and the effects of the uncertainty in solid surface emissivity are also investigated. (authors)
Viscosity of a nucleonic fluid
Aram Z. Mekjian
2012-03-21T23:59:59.000Z
The viscosity of nucleonic matter is studied both classically and in a quantum mechanical description. The collisions between particles are modeled as hard sphere scattering as a baseline for comparison and as scattering from an attractive square well potential. Properties associated with the unitary limit are developed which are shown to be approximately realized for a system of neutrons. The issue of near perfect fluid behavior of neutron matter is remarked on. Using some results from hard sphere molecular dynamics studies near perfect fluid behavior is discussed further.
Thermophysical Properties of Fluids and Fluid Mixtures
Sengers, Jan V.; Anisimov, Mikhail A.
2004-05-03T23:59:59.000Z
The major goal of the project was to study the effect of critical fluctuations on the thermophysical properties and phase behavior of fluids and fluid mixtures. Long-range fluctuations appear because of the presence of critical phase transitions. A global theory of critical fluctuations was developed and applied to represent thermodynamic properties and transport properties of molecular fluids and fluid mixtures. In the second phase of the project, the theory was extended to deal with critical fluctuations in complex fluids such as polymer solutions and electrolyte solutions. The theoretical predictions have been confirmed by computer simulations and by light-scattering experiments. Fluctuations in fluids in nonequilibrium states have also been investigated.
Jake P. Gentle; Kurt S Myers; Tyler B Phillips; Inanc Senocak; Phil Anderson
2014-08-01T23:59:59.000Z
Dynamic Line Rating (DLR) is a smart grid technology that allows the rating of power line to be based on real-time conductor temperature dependent on local weather conditions. In current practice overhead power lines are generally given a conservative rating based on worst case weather conditions. Using historical weather data collected over a test bed area, we demonstrate there is often additional transmission capacity not being utilized with the current static rating practice. We investigate a new dynamic line rating methodology using computational fluid dynamics (CFD) to determine wind conditions along transmission lines at dense intervals. Simulated results are used to determine conductor temperature by calculating the transient thermal response of the conductor under variable environmental conditions. In calculating the conductor temperature, we use both a calculation with steady-state assumption and a transient calculation. Under low wind conditions, steady-state assumption predicts higher conductor temperatures that could lead to curtailments, whereas transient calculations produce conductor temperatures that are significantly lower, implying the availability of additional transmission capacity.
Lisal, Martin
Z .Fluid Phase Equilibria 161 1999 241256 Vaporliquid equilibrium, fluid state, and zero-pressure but independent constant pressureconstant temperature Z .molecular dynamics simulations of the vapor and liquid. Keywords: Chlorine; Intermolecular potential; Molecular simulation; Vaporliquid equilibria; Vapor pressure
CFD Analyses of Damaged Fuel Inside a Cleaning Vessel
Legradi, Gabor; Boros, Ildiko; Aszodi, Attila [Budapest University of Technology and Economics, Muegyetem rkp. 3-9. H-1111 Budapest (Hungary)
2006-07-01T23:59:59.000Z
On 10-11 of April, 2003, a serious incident occurred in a special fuel assembly cleaning tank, which was installed into the service shaft of the 2. unit of the Paks NPP in Hungary. During this incident, most of the 30 fuel assemblies put into the cleaning tank have seriously damaged. In the Institute of Nuclear Techniques of the Budapest University of Technology and Economics several CFD investigations were performed concerning the course of the incident, the post incidental conditions and the recovery work. The main reason of the incident can be originated from the defective design of the cleaning tank which resulted in the insufficient cooling of the system in a special operational mode. Our investigation performed with a complex 3D CFX model clearly showed how could as strong temperature stratification develop inside the cleaning tank that it was able to block the coolant flow through the fuel assemblies. After the blocking of the flow, the coolant turned into boiling and the assemblies became uncovered. The temperature of the surfaces of the fuel assemblies went above 1000 deg. C. With the aid of the radiative heat transfer model of the CFX-5.6 code, the surface temperatures were analyzed. When the cleaning instrument got opened the fuel assemblies suffered a serious thermal shock and the assemblies highly damaged. The post-incident thermo-hydraulic state inside the cleaning vessel was investigated with a rather complex CFX model. The uncertainties were decreased by a wide parameter study. The recovery work is planned to be started in the close future. The operators of the damaged fuel removing equipments will work standing on a platform which will be placed into the service shaft just above the surface of the coolant of decreased level. Protecting the workers against unnecessary personal doses is a very important task. In this situation, while the coolant is important part of the biological shielding, it is also a source of radiation due to the considerable amount of radioactive contamination dispersed into it. Therefore, the 3D distribution of the contamination in the service shaft was estimated for different operational and incidental scenarios with a wide parameter study made by a 3D CFX model. This comprehensive work performed with several models and calculations is tersely outlined according to the limited extent of the paper. (authors)
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Dilley, Lorie
Fluid inclusion gas analysis for wells in various geothermal areas. Analyses used in developing fluid inclusion stratigraphy for wells and defining fluids across the geothermal fields. Each sample has mass spectrum counts for 180 chemical species.
Dilley, Lorie
2013-01-01T23:59:59.000Z
Fluid inclusion gas analysis for wells in various geothermal areas. Analyses used in developing fluid inclusion stratigraphy for wells and defining fluids across the geothermal fields. Each sample has mass spectrum counts for 180 chemical species.
Dynamic modeling of a single-stage downward firing, entrained flow gasifier
Kasule, J., Turton, R., Bhattacharyya, D., Zitney, S.
2012-01-01T23:59:59.000Z
The gasifier is the heart of the integrated gasification combined cycle (IGCC), a technology that has emerged as an attractive alternative to conventional coal-fired power plant technology due to its higher efficiency and cleaner environmental performance especially with the option of CO{sub 2} capture and sequestration. Understanding the optimal performance of the gasifier is therefore paramount for the efficient operation of IGCC power plants. Numerous gasifier models of varying complexity have been developed to study the various aspects of gasifier performance. These range from simple one-dimensional (1D) process-type models to rigorous higher order 2-3D models based on computational fluid dynamics (CFD). Whereas high-fidelity CFD models can accurately predict most key aspects of gasifier performance, they are computationally expensive and typically take hours to days to execute on high-performance computers. Therefore, faster 1D partial differential equation (PDE)-based models are required for use in dynamic simulation studies, control system analysis, and training applications. A number of 1D gasifier models can be found in the literature, but most are steady-state models that have limited application in the practical operation of the gasifier. As a result, 1D PDE-based dynamic models are needed to further study and predict gasifier performance under a wide variety of process conditions and disturbances. In the current study, a 1D transient model of a single-stage downward-fired GE/Texaco-type entrained-flow gasifier has been developed. The model comprises mass, momentum and energy balances for the gas and solid phases. The model considers the initial gasification processes of water evaporation and coal devolatilization. In addition, the key heterogeneous and homogeneous chemical reactions have been modeled. The resulting time-dependent PDE model is solved using the well-known method of lines approach in Aspen Custom Modeler®, whereby the PDEs in the spatial domain are discretized and the resulting differential algebraic equations (DAEs) are then integrated over time using a dynamic integrator. The dynamic response results of the gasifier performance parameters to certain disturbances commonly encountered during practical operation are presented. These disturbances include ramp and step changes to input variables such as coal flow rate, oxygen-to-coal ratio and water-to-coal ratio among others. Comparison of model predictions to available dynamic data will also be discussed.
Friction-Induced Fluid Heating in Nanoscale Helium Flows
Li Zhigang [Department of Mechanical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)
2010-05-21T23:59:59.000Z
We investigate the mechanism of friction-induced fluid heating in nanoconfinements. Molecular dynamics simulations are used to study the temperature variations of liquid helium in nanoscale Poiseuille flows. It is found that the fluid heating is dominated by different sources of friction as the external driving force is changed. For small external force, the fluid heating is mainly caused by the internal viscous friction in the fluid. When the external force is large and causes fluid slip at the surfaces of channel walls, the friction at the fluid-solid interface dominates over the internal friction in the fluid and is the major contribution to fluid heating. An asymmetric temperature gradient in the fluid is developed in the case of nonidentical walls and the general temperature gradient may change sign as the dominant heating factor changes from internal to interfacial friction with increasing external force.
Solution characters of iterative coupling between energy simulation and CFD programs
Zhai, John Z.
States, building services consume more than one third of the primary energy consumption and twoSolution characters of iterative coupling between energy simulation and CFD programs Zhiqiang Zhaia Massachusetts Avenue, Cambridge, MA 02139-4307, USA b School of Mechanical Engineering, Purdue University, 1288
Wind power resource assessment in complex urban environments: MIT campus case-study using CFD of Technology, 2Meteodyn Objectives Conclusions References [1] TopoWind software, User Manual [2] Wind Resource Assessment Handbook: Fundamentals for Conducting a Successful Wind Monitoring Program, AWS Scientific, Inc
Dual-level parallelism for high-order CFD methods q
Dong, Suchuan "Steven"
MP shared-memory parallelization and employ a work- load-splitting scheme that reduces the OpenDual-level parallelism for high-order CFD methods q Suchuan Dong, George Em Karniadakis * Division-order methods and implemented in the spectral/hp element framework to take advantage of the hierarchical
http://rcc.its.psu.edu/hpc Advanced CFD Models for Next-Generation Combustion Systems
Bjørnstad, Ottar Nordal
http://rcc.its.psu.edu/hpc Advanced CFD Models for Next-Generation Combustion Systems S: Requirements for next-generation combustion systems include: Increased performance, Reduced fuel consumption, and for direct-injection diesel engines Models carried intact from simulations of laboratory flames give good
SENSITIVITY ANALYSIS AND APPLICATION GUIDES FOR INTEGRATED BUILDING ENERGY AND CFD SIMULATION
Chen, Qingyan "Yan"
1 SENSITIVITY ANALYSIS AND APPLICATION GUIDES FOR INTEGRATED BUILDING ENERGY AND CFD SIMULATION Engineering Purdue University 585 Purdue Mall, West Lafayette, IN 47907-2088, USA Abstract Building energy suggestions on appropriate usage of the coupling simulation are provided. 1. Introduction Building energy
3-D Time-Accurate CFD Simulations of Wind Turbine Rotor Flow Fields
3-D Time-Accurate CFD Simulations of Wind Turbine Rotor Flow Fields Nilay Sezer-Uzol and Lyle N around the National Renewable Energy Laboratory (NREL) Phase VI horizontal axis wind turbine rotor. The 3 turbulent flow that generates the noise, in the context of the wind turbine application. I. Introduction
A Multi-FhJid CFD Turbulent Entrainment Combustion Model: Formulation and One-Dimensional Results
conservation, correctly predicts the jump in mass, energy and momentum across the flame, retains all regulations for spark· ignited (SI) internal combustion engines requires understanding the complex chemical In this paper, we present a new formulation for have been integrated into multi-dimensional CFD codes
Comparative Analysis of CFD ?P vs. Measured ?P for Compressed Flexible Ducts
Ugursal, A.; Culp, C.H.
2007-01-01T23:59:59.000Z
with permission of the copyright owner. Further reproduction prohibited without permission. Comparative Analysis of CFD [Delta]P vs. Measured [Delta]P for Compressed Flexible Ducts Ugursal, Ahmet;Culp, Charles ASHRAE Transactions; 2007; 113, ProQuest pg. 462...
Performance Evaluation and CFD Simulation of Multiphase Twin-Screw Pumps
Patil, Abhay
2013-05-16T23:59:59.000Z
and velocity profile agreed well with previous studies. Results are validated using an analytical approach as well as experimental data. A two-phase CFD simulation was performed for 50% GVF. An Eulerian approach was employed to evaluate multiphase flow behavior...
Post-Doc and Staff Engineer Positions in CFD and Mesh Generation July 10, 2014
of large-scale computations for fuel cell and battery devices. We are looking for talented, ambitious and fuel cells for vehicle electrification, renewable energy storage, and power grid management. The group in electrochemistry, materials, manufacturing, diagnostics, CFD modeling, and system engineering. The center has
A Be%er Understanding of the Earth System Through Advances in CFD
Wang, Zhi Jian "ZJ"
A Be%er Understanding of the Earth System Through Advances in CFD Paul Ullrich for atmospheric models that can harness these large-scale parallel systems. Higher University of California, Davis June 22nd, 2013 #12;Part 1 Atmospheric Models and the Need for Resolution #12
Kochevsky, A N
2005-01-01T23:59:59.000Z
The paper describes capabilities of numerical simulation of liquid flows with solid and/or gas admixtures in centrifugal pumps using modern commercial CFD software packages, with the purpose to predict performance curves of the pumps treating such media. In particular, the approaches and multiphase flow models available in the package CFX-5 are described; their advantages and disadvantages are analyzed.
Performance and safety of rooftop wind turbines: Use of CFD to gain insight into inflow conditions
McCalley, James D.
to overcome, including energy yield reduction due to lower mean wind speeds in urban areas, and environmental as well as environmental impacts [5]. There have been some very public failures of small wind turbines and assesses the possibility of combining a CFD package with wind atlas software to form a wind energy resource
Modeling of a MEMS Floating Element Shear Sensor Nikolas Kastor 1
White, Robert D.
, a computational fluid dynamics (CFD) model is described. The CFD model directly models a laminar flow cell, there are concerns about the validity of laminar flow cell calibration to measurement in turbulent flows by the flowing fluid; the deflection of the sensing element as a result of those fluid forces
Washington State University Vancouver Mech 303 Fluid Mechanics Mechanical Engineering Fall 2013 Syllabus 1 Fluid Mechanics Course: Mech 303, Fluid Mechanics, 3 Credits Prerequisite: Dynamics (Mech 212: VECS 105 Textbook: Fundamentals of Fluid Mechanics, 7 th Edition By Munson, Okiishi, Huebsch
Bonne, U.; Vesovic, V.; Wakeham, W.A.
1996-07-15T23:59:59.000Z
The set published properties of gases constituting natural gas, at pressures up to 300 basr (4500 psi) ad for -40 less than or equal to T less than or equal to 250 deg C, is not accurate or consistent enough for members of hte gas industry, research groups, NGV-automotive engineers, and meter manufacturers to nondestructively calibrate existing, affordable, combustionless, on-line and in situ microsensors for their applications. Therefore, this study was set up to (1) establish a consistent set of thermophysical properties (thermal conductivity, viscosity, and isobaric heat capacity) of pure and mixed gas constituents of natural gases and (2) prove the validity and limitations of using one or more point sensors in suitable flow channels for the determination of total fluid flow.
Relativistic Elasticity of Stationary Fluid Branes
Jay Armas; Niels A. Obers
2012-10-18T23:59:59.000Z
Fluid mechanics can be formulated on dynamical surfaces of arbitrary co-dimension embedded in a background space-time. This has been the main object of study of the blackfold approach in which the emphasis has primarily been on stationary fluid configurations. Motivated by this approach we show under certain conditions that a given stationary fluid configuration living on a dynamical surface of vanishing thickness and satisfying locally the first law of thermodynamics will behave like an elastic brane when the surface is subject to small deformations. These results, which are independent of the number of space-time dimensions and of the fluid arising from a gravitational dual, reveal the (electro)elastic character of (charged) black branes when considering extrinsic perturbations.
Relativistic Elasticity of Stationary Fluid Branes
Armas, Jay
2012-01-01T23:59:59.000Z
Fluid mechanics can be formulated on dynamical surfaces of arbitrary co-dimension embedded in a background space-time. This has been the main object of study of the blackfold approach in which the emphasis has primarily been on stationary fluid configurations. Motivated by this approach we show under certain conditions that a given stationary fluid configuration living on a dynamical surface of vanishing thickness and satisfying locally the first law of thermodynamics will behave like an elastic brane when the surface is subject to small deformations. These results, which are independent of the number of space-time dimensions and of the fluid arising from a gravitational dual, reveal the (electro)elastic character of (charged) black branes when considering extrinsic perturbations.
Conformal higher-order viscoelastic fluid mechanics
Masafumi Fukuma; Yuho Sakatani
2012-05-28T23:59:59.000Z
We present a generally covariant formulation of conformal higher-order viscoelastic fluid mechanics with strain allowed to take arbitrarily large values. We give a general prescription to determine the dynamics of a relativistic viscoelastic fluid in a way consistent with the hypothesis of local thermodynamic equilibrium and the second law of thermodynamics. We then elaborately study the transient time scales at which the strain almost relaxes and becomes proportional to the gradients of velocity. We particularly show that a conformal second-order fluid with all possible parameters in the constitutive equations can be obtained without breaking the hypothesis of local thermodynamic equilibrium, if the conformal fluid is defined as the long time limit of a conformal second-order viscoelastic system. We also discuss how local thermodynamic equilibrium could be understood in the context of the fluid/gravity correspondence.
Theory of locomotion through complex fluids
Gwynn Elfring; Eric Lauga
2014-10-16T23:59:59.000Z
Microorganisms such as bacteria often swim in fluid environments that cannot be classified as Newtonian. Many biological fluids contain polymers or other heterogeneities which may yield complex rheology. For a given set of boundary conditions on a moving organism, flows can be substantially different in complex fluids, while non-Newtonian stresses can alter the gait of the microorganisms themselves. Heterogeneities in the fluid may also be characterized by length scales on the order of the organism itself leading to additional dynamic complexity. In this chapter we present a theoretical overview of small-scale locomotion in complex fluids with a focus on recent efforts quantifying the impact of non-Newtonian rheology on swimming microorganisms.
DeRoos, B.G.; Downing, J.P. Jr.; Neal, M.P.
1995-11-14T23:59:59.000Z
An improved fluid container for the transport, collection, and dispensing of a sample fluid that maintains the fluid integrity relative to the conditions of the location at which it is taken. More specifically, the invention is a fluid sample transport container that utilizes a fitting for both penetrating and sealing a storage container under controlled conditions. Additionally, the invention allows for the periodic withdrawal of portions of the sample fluid without contamination or intermixing from the environment surrounding the sample container. 13 figs.
On the Hamiltonian Description of Fluid Mechanics
I. Antoniou; G. P. Pronko
2002-03-14T23:59:59.000Z
We suggest the Hamiltonian approach for fluid mechanics based on the dynamics, formulated in terms of Lagrangian variables. The construction of the canonical variables of the fluid sheds a light of the origin of Clebsh variables, introduced in the previous century. The developed formalism permits to relate the circulation conservation (Tompson theorem) with the invariance of the theory with respect to special diffiomorphisms and establish also the new conservation laws. We discuss also the difference of the Eulerian and Lagrangian description, pointing out the incompleteness of the first. The constructed formalism is also applicable for ideal plasma. We conclude with several remarks on the quantization of the fluid.
Control of underactuated fluid-body systems with real-time particle image velocimetry
Roberts, John W., Ph. D. Massachusetts Institute of Technology
2012-01-01T23:59:59.000Z
Controlling the interaction of a robot with a fluid, particularly when the desired behavior is intimately related to the dynamics of the fluid, is a difficult and important problem. High-performance aircraft cannot ignore ...
A numerical framework for the direct simulation of solid-fluid systems
Cook, Benjamin Koger, 1965-
2001-01-01T23:59:59.000Z
Our understanding of solid-fluid dynamics has been severely limited by the nonexistence of a high-fidelity modeling capability for these multiphase systems. Continuum modeling approaches overlook the microscale solid-fluid ...
Standardization of Thermo-Fluid Modeling in Modelica.Fluid
Franke, Rudiger
2010-01-01T23:59:59.000Z
Thermo-Fluid Systems, Modelica 2003 Conference, Linköping,H. Tummescheit: The Modelica Fluid and Media Library forThermo-Fluid Pipe Networks, Modelica 2006 Conference, Vi-
Lenert, Andrej
2012-01-01T23:59:59.000Z
The choice of heat transfer fluids has significant effects on the performance, cost, and reliability of solar thermal systems. In this chapter, we evaluate existing heat transfer fluids such as oils and molten salts based ...
Forrest, G.T.
1992-04-07T23:59:59.000Z
This patent describes a product for use in the drilling of wells. It comprises a drilling fluid and peanut hulls ground to powder form added to the drilling fluid.
Standardization of Thermo-Fluid Modeling in Modelica.Fluid
Franke, Rudiger
2010-01-01T23:59:59.000Z
Ob- ject-Oriented Modeling of Thermo-Fluid Systems, Modelicable and Compressible Thermo-Fluid Pipe Networks, ModelicaStandardization of Thermo-Fluid Modeling in Modelica.Fluid
Entropy production at freeze-out from dissipative fluids
E. Molnar
2007-09-17T23:59:59.000Z
Entropy production due to shear viscosity during the continuous freeze-out of a longitudinally expanding dissipative fluid is addressed. Assuming the validity of the fluid dynamical description during the continuous removal of interacting matter we estimated a small entropy production as function of the freeze-out duration and the ratio of dissipative to non-dissipative quantities in case of a relativistic massless pion fluid.
Broader source: Energy.gov [DOE]
Presentation given by Argonne National Laboratory at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about CFD simulations...
A thin film model for corotational Jeffreys fluids under strong slip
A. Münch; B. Wagner; M. Rauscher; R. Blossey
2006-05-14T23:59:59.000Z
We derive a thin film model for viscoelastic liquids under strong slip which obey the stress tensor dynamics of corotational Jeffreys fluids.
Carbon-bearing fluids at nanoscale interfaces
Cole, David [Ohio State University; Ok, Salim [Ohio State University, Columbus; Phan, A [Ohio State University, Columbus; Rother, Gernot [ORNL; Striolo, Alberto [Oklahoma University; Vlcek, Lukas [ORNL
2013-01-01T23:59:59.000Z
The behaviour of fluids at mineral surfaces or in confined geometries (pores, fractures) typically differs from their bulk behaviour in many ways due to the effects of large internal surfaces and geometrical confinement. We summarize research performed on C-O-H fluids at nanoscale interfaces in materials of interest to the earth and material sciences (e.g., silica, alumina, zeolites, clays, rocks, etc.), emphasizing those techniques that assess microstructural modification and/or dynamical behaviour such as gravimetric analysis, small-angle (SANS) neutron scattering, and nuclear magnetic resonance (NMR). Molecular dynamics (MD) simulations will be described that provide atomistic characterization of interfacial and confined fluid behaviour as well as aid in the interpretation of the neutron scattering results.
Miller, Jan D; Hupka, Jan; Aranowski, Robert
2012-11-20T23:59:59.000Z
A spinning fluids reactor, includes a reactor body (24) having a circular cross-section and a fluid contactor screen (26) within the reactor body (24). The fluid contactor screen (26) having a plurality of apertures and a circular cross-section concentric with the reactor body (24) for a length thus forming an inner volume (28) bound by the fluid contactor screen (26) and an outer volume (30) bound by the reactor body (24) and the fluid contactor screen (26). A primary inlet (20) can be operatively connected to the reactor body (24) and can be configured to produce flow-through first spinning flow of a first fluid within the inner volume (28). A secondary inlet (22) can similarly be operatively connected to the reactor body (24) and can be configured to produce a second flow of a second fluid within the outer volume (30) which is optionally spinning.
Fedosov, Dmitry A; Gompper, Gerhard
2015-01-01T23:59:59.000Z
Janus colloids propelled by light, e.g., thermophoretic particles, offer promising prospects as artificial microswimmers. However, their swimming behavior and its dependence on fluid properties and fluid-colloid interactions remain poorly understood. Here, we investigate the behavior of a thermophoretic Janus colloid in its own temperature gradient using numerical simulations. The dissipative particle dynamics method with energy conservation is used to investigate the behavior in non-ideal and ideal-gas like fluids for different fluid-colloid interactions, boundary conditions, and temperature-controlling strategies. The fluid-colloid interactions appear to have a strong effect on the colloid behavior, since they directly affect heat exchange between the colloid surface and the fluid. The simulation results show that a reduction of the heat exchange at the fluid-colloid interface leads to an enhancement of colloid's thermophoretic mobility. The colloid behavior is found to be different in non-ideal and ideal f...
Hipolito-Ricaldi, W. S. [Universidade Federal do Espirito Santo, Departamento de Ciencias Matematicas e Naturais, CEUNES, Rodovia BR 101 Norte, km. 60, CEP 29932-540, Sao Mateus, Espirito Santo (Brazil); Velten, H. E. S.; Zimdahl, W. [Universidade Federal do Espirito Santo, Departamento de Fisica, Av. Fernando Ferrari, 514, Campus de Goiabeiras, CEP 29075-910, Vitoria, Espirito Santo (Brazil)
2010-09-15T23:59:59.000Z
We investigate the cosmological perturbation dynamics for a universe consisting of pressureless baryonic matter and a viscous fluid, the latter representing a unified model of the dark sector. In the homogeneous and isotropic background the total energy density of this mixture behaves as a generalized Chaplygin gas. The perturbations of this energy density are intrinsically nonadiabatic and source relative entropy perturbations. The resulting baryonic matter power spectrum is shown to be compatible with the 2dFGRS and SDSS (DR7) data. A joint statistical analysis, using also Hubble-function and supernovae Ia data, shows that, different from other studies, there exists a maximum in the probability distribution for a negative present value q{sub 0{approx_equal}}-0.53 of the deceleration parameter. Moreover, while previous descriptions on the basis of generalized Chaplygin-gas models were incompatible with the matter power-spectrum data since they required a much too large amount of pressureless matter, the unified model presented here favors a matter content that is of the order of the baryonic matter abundance suggested by big-bang nucleosynthesis.
Mailhes, Corinne
, and biomass gasi- fication. Since few years, the development of computational ability and Computational Fluid Dynamic (CFD) allows 3-dimensional realistic simulations of industrial configura- tions by using eulerian multi-fluid approach. In the application of CFD models, careful validation with experimental
Ying, D.H.S.; Sivasubramanian, R.; Moujaes, S.F.; Givens, E.N.
1982-04-01T23:59:59.000Z
A commercial coal liquefaction plant will employ vertical tubular reactors feeding slurry and gas concurrently upward through these vessels. In the SRC-I plant design the reactor is essentially an empty vessel with only a distributor plate located near the inlet. Because the commercial plant represents a considerable scale-up over Wilsonville or any pilot plant, this program addressed the need for additional data on behavior of three phase systems in large vessels. Parameters that were investigated in this program were studied at conditions that relate directly to projected plant operating conditions. The fluid dynamic behavior of the three-phase upflow system was studied by measuring gas and slurry holdup, liquid dispersion, solids suspension and solids accumulation. The dependent parameters are gas and liquid velocities, solid particle size, solids concentration, liquid viscosity, liquid surface tension and inlet distributor. Within the range of liquid superficial velocity from 0.0 to 0.5 ft/sec, gas holdup is found to be independent of liquid flow which agrees with other investigators. The results also confirm our previous finding that gas holdup is independent of column diameter when the column diameter is 5 inches or larger. The gas holdup depends strongly on gas flow rate; gas holdup increases with increasing gas velocity. The effect of solids particles on gas holdup depends on the gas flow rate. Increasing liquid viscosity and surface tension reduce gas holdup which agrees with other investigators. Because of the complexity of the system, we could not find a single correlation to best fit all the data. The degree of liquid backmixing markedly affects chemical changes occurring in the dissolver, such as sulfur removal, and oil and distillate formation.
Angel, S.M.
1987-02-27T23:59:59.000Z
Particular gases or liquids are detected with a fiber optic element having a cladding or coating of a material which absorbs the fluid or fluids and which exhibits a change of an optical property, such as index of refraction, light transmissiveness or fluoresence emission, for example, in response to absorption of the fluid. The fluid is sensed by directing light into the fiber optic element and detecting changes in the light, such as exit angle changes for example, that result from the changed optical property of the coating material. The fluid detector may be used for such purposes as sensing toxic or explosive gases in the atmosphere, measuring ground water contamination or monitoring fluid flows in industrial processes, among other uses. 10 figs.
Angel, S. Michael (Livermore, CA)
1989-01-01T23:59:59.000Z
Particular gases or liquids are detected with a fiber optic element (11, 11a to 11j) having a cladding or coating of a material (23, 23a to 23j) which absorbs the fluid or fluids and which exhibits a change of an optical property, such as index of refraction, light transmissiveness or fluoresence emission, for example, in response to absorption of the fluid. The fluid is sensed by directing light into the fiber optic element and detecting changes in the light, such as exit angle changes for example, that result from the changed optical property of the coating material. The fluid detector (24, 24a to 24j) may be used for such purposes as sensing toxic or explosive gases in the atmosphere, measuring ground water contamination or monitoring fluid flows in industrial processes, among other uses.
Metalworking and machining fluids
Erdemir, Ali (Naperville, IL); Sykora, Frank (Caledon, ON, CA); Dorbeck, Mark (Brighton, MI)
2010-10-12T23:59:59.000Z
Improved boron-based metal working and machining fluids. Boric acid and boron-based additives that, when mixed with certain carrier fluids, such as water, cellulose and/or cellulose derivatives, polyhydric alcohol, polyalkylene glycol, polyvinyl alcohol, starch, dextrin, in solid and/or solvated forms result in improved metalworking and machining of metallic work pieces. Fluids manufactured with boric acid or boron-based additives effectively reduce friction, prevent galling and severe wear problems on cutting and forming tools.
L3: THM.CFD.P9.06 Enhanced Turbulence
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:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article)41clothThe Bonneville PowerTariff Pages default Sign In AboutIsrelocates I UCRLr90790 R E V . 1-a 1 VUQ:THM.CFD.P9.06
Development of CFD-Based Simulation Tools for In-Situ Thermal Processing of
Office of Scientific and Technical Information (OSTI)
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:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports to3,1,50022,3,,0,,6,1,Separation 23Tribal EnergyCatalyticPreparation and propertiessystemDOSFAC2 user`s guideState of the ArtandCFD-Based
Petascale, Adaptive CFD (ALCF ESP Technical Report): ALCF-2 Early Science
Office of Scientific and Technical Information (OSTI)
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:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports to3,1,50022,3,,0,,6,1,Separation 23Tribal EnergyCatalyticPreparation andEnablingFiftyThird-Harmonic GenerationPRRCPetascale, Adaptive CFD
GG 711: Theoretical Fluid Mechanics Instructor: Janet Becker (janetbec@hawaii.edu)
GG 711: Theoretical Fluid Mechanics Fall 2015 Instructor: Janet Becker (janetbec and Reid · Additional References: 1. Lectures on Geophysical Fluid Dynamics by Rick Salmon 2. Perturbation reference and (2) as a fluids course where advanced mathematical tech- inques are used to solve problems
American Institute of Aeronautics and Astronautics Coupled Level-Set/Volume-of-Fluid Method for the
Sussman, Mark
utilizing a coupled level-set/volume-of-fluid method to simulate liquid fuel atomization. The coupledAmerican Institute of Aeronautics and Astronautics 1 Coupled Level-Set/Volume-of-Fluid Method, Canoga Park, Calif. 91309 This paper presents results of a multiphase computational fluid dynamics code
Flow networks: A characterization of geophysical fluid transport
Enrico Ser-Giacomi; Vincent Rossi; Cristobal Lopez; Emilio Hernandez-Garcia
2015-03-05T23:59:59.000Z
We represent transport between different regions of a fluid domain by flow networks, constructed from the discrete representation of the Perron-Frobenius or transfer operator associated to the fluid advection dynamics. The procedure is useful to analyze fluid dynamics in geophysical contexts, as illustrated by the construction of a flow network associated to the surface circulation in the Mediterranean sea. We use network-theory tools to analyze the flow network and gain insights into transport processes. In particular we quantitatively relate dispersion and mixing characteristics, classically quantified by Lyapunov exponents, to the degree of the network nodes. A family of network entropies is defined from the network adjacency matrix, and related to the statistics of stretching in the fluid, in particular to the Lyapunov exponent field. Finally we use a network community detection algorithm, Infomap, to partition the Mediterranean network into coherent regions, i.e. areas internally well mixed, but with little fluid interchange between them.
MECH 386 INDUSTRIAL FLUID MECHANICS INDUSTRIAL FLUID MECHANICS
Phani, A. Srikantha
MECH 386 INDUSTRIAL FLUID MECHANICS 1 INDUSTRIAL FLUID MECHANICS MECH 386 Contact information Dr This course is an introduction to industrial fluid mechanics. According to J. C. R. Hunt (a famous fluid mechanics specialist): "industrial fluid mechanics broadly covers those aspects of the design, manufacture
Fees are subject to change. See studyguide.au.dk *PLACE OF STUDY
such as fluid dynamics (CFD), structural dynamics and modal analysis, and fracture mechanics and fatigue Wind Power #12; include: How do you design the blades of a wind turbine? How do you calculate the lifetime of a computer
General purpose steam table library : CASL L3:THM.CFD.P7.04 milestone report.
Carpenter, John H.; Belcourt, Noel; Nourgaliev, Robert
2013-08-01T23:59:59.000Z
Completion of the CASL L3 milestone THM.CFD.P7.04 provides a general purpose tabular interpolation library for material properties to support, in particular, standardized models for steam properties. The software consists of three parts, implementations of analytic steam models, a code to generate tables from those models, and an interpolation package to interface the tables to CFD codes such as Hydra-TH. Verification of the standard model is maintained through the entire train of routines. The performance of interpolation package exceeds that of freely available analytic implementation of the steam properties by over an order of magnitude.
Statistical mechanics of homogeneous partly pinned fluid systems
Vincent Krakoviack
2010-12-05T23:59:59.000Z
The homogeneous partly pinned fluid systems are simple models of a fluid confined in a disordered porous matrix obtained by arresting randomly chosen particles in a one-component bulk fluid or one of the two components of a binary mixture. In this paper, their configurational properties are investigated. It is shown that a peculiar complementarity exists between the mobile and immobile phases, which originates from the fact that the solid is prepared in presence of and in equilibrium with the adsorbed fluid. Simple identities follow, which connect different types of configurational averages, either relative to the fluid-matrix system or to the bulk fluid from which it is prepared. Crucial simplifications result for the computation of important structural quantities, both in computer simulations and in theoretical approaches. Finally, possible applications of the model in the field of dynamics in confinement or in strongly asymmetric mixtures are suggested.
Simulations of Particle Dynamics in Magnetorheological Fluids
are accounted for via Stokes' drag while interparticle repulsions are modeled through approximate hardspherestatic and magnetostatic forces are de rived from the solution of (steady) Maxwell's equations, recomputed at each instant
OpenFOAM: Computational Fluid Dynamics
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:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5(Million Cubic Feet) Oregon (Including Vehicle Fuel) (Million Cubic Feet) NaturalOctober OctoberResolved: Pathscale/4.0.9 notHopperâ†’ global â†’Issues
OpenFOAM: Computational Fluid Dynamics
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:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5(Million Cubic Feet) Oregon (Including Vehicle Fuel) (Million Cubic Feet) NaturalOctober OctoberResolved: Pathscale/4.0.9 notHopperâ†’ global
Morphing quantum mechanics and fluid dynamics
Thomas Curtright; David Fairlie
2003-05-28T23:59:59.000Z
We investigate the effects of given pressure gradients on hydrodynamic flow equations. We obtain results in terms of implicit solutions and also in the framework of an extra-dimensional formalism involving the diffusion/Schrodinger equation.
Eggers, Jens
to the large scale distribution of matter in the universe. For most of the 20th century, it has been of propane coming out of a gold nozzle 6 nm in diameter, from Moseler and Landman, Science 289, 1165 (2000). There are about 2 × 105 propane molecules in this simulation. On the left, one sees the formation of the jet
Fluid Dynamics IB Dr Natalia Berloff
would usually be called a `hydraulic jump'. Turbulent energy loss in the transition region can be so and hydraulic jumps* [`bore' as in `drill', or `penetrate'. E.g. the famous `Severn bore'.] By far the biggest km. #12;Bores and hydraulic jumps are essentially the same thing viewed in different frames
CFD Simulation of 3D Flow field in a Gas Centrifuge
Dongjun Jiang; Shi Zeng [Tsinghua University, Beijing, 100084 (China)
2006-07-01T23:59:59.000Z
A CFD method was used to study the whole flow field in a gas centrifuge. In this paper, the VSM (Vector Splitting Method) of the FVM (Finite Volume Method) was used to solve the 3D Navier-Stokes equations. An implicit second-order upwind scheme was adopted. The numerical simulation was successfully performed on a parallel cluster computer and a convergence result was obtained. The simulation shows that: in the withdrawal chamber, a strong detached shock wave is formed in front of the scoop; as the radial position increases, the shock becomes stronger and the distance to scoop front surface is smaller. An oblique shock forms in the clearance between the scoop and the centrifuge wall; behind the shock-wave, the radially-inward motion of gas is induced because of the imbalance of the pressure gradient and the centrifugal force. In the separation chamber, a countercurrent is introduced. This indicates that CFD method can be used to study the complex three-dimensional flow field of gas centrifuges. (authors)
Hoff, Brian D.; Johnson, Kris William; Algrain, Marcelo C.; Akasam, Sivaprasad
2006-06-06T23:59:59.000Z
A method of controlling the delivery of fluid to an engine includes receiving a fuel flow rate signal. An electric pump is arranged to deliver fluid to the engine. The speed of the electric pump is controlled based on the fuel flow rate signal.
Jakaboski, Juan-Carlos (Albuquerque, NM); Hughs, Chance G. (Albuquerque, NM); Todd, Steven N. (Rio Rancho, NM)
2012-01-10T23:59:59.000Z
A fluid blade disablement (FBD) tool that forms both a focused fluid projectile that resembles a blade, which can provide precision penetration of a barrier wall, and a broad fluid projectile that functions substantially like a hammer, which can produce general disruption of structures behind the barrier wall. Embodiments of the FBD tool comprise a container capable of holding fluid, an explosive assembly which is positioned within the container and which comprises an explosive holder and explosive, and a means for detonating. The container has a concavity on the side adjacent to the exposed surface of the explosive. The position of the concavity relative to the explosive and its construction of materials with thicknesses that facilitate inversion and/or rupture of the concavity wall enable the formation of a sharp and coherent blade of fluid advancing ahead of the detonation gases.
Yield stresses in electrorheological fluids R. T. Bonnecazea) and J. F. Brady
previously for the dynamic simulation of an ER fluid. The static yield stress is determined from nonlinear;Gast & Zukoski, 1989; Klingenberg, 1990) and dynamic simulations (Klingenberg, 1990; Bonnecaze & Brady, dominates the rheology of the ER fluid at large electric field strengths. At the sametime the electrostatic
A two-fluid model for relativistic heat conduction
López-Monsalvo, César S. [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México (Mexico)
2014-01-14T23:59:59.000Z
Three years ago it was presented in these proceedings the relativistic dynamics of a multi-fluid system together with various applications to a set of topical problems [1]. In this talk, I will start from such dynamics and present a covariant formulation of relativistic thermodynamics which provides us with a causal constitutive equation for the propagation of heat in a relativistic setting.
Computer Vision in Fluid Mechanics
Aminfar, AmirHessam
2015-01-01T23:59:59.000Z
layers," Journal of Fluid Mechanics, vol. 30, no. 04, pp.M. Princevac, "Fundamental fluid mechanics," 2014. C. W.Computer Vision in Fluid Mechanics A Thesis submitted in
Computer Vision in Fluid Mechanics
Aminfar, AmirHessam
2015-01-01T23:59:59.000Z
layers," Journal of Fluid Mechanics, vol. 30, no. 04, pp.Fundamental fluid mechanics," 2014. C. W. Enderlin, "MacroComputer Vision in Fluid Mechanics A Thesis submitted in
CFD Analysis of a Novel High Speed Rotary On/Off Valve 283 Proc. of 6th
Li, Perry Y.
that predict the valve performance has been validated for the inlet rail with nozzles and the outlet turbine section, and outlet turbine. A CFD model is created for each section, and then verified. The equations, valve design, throttle-less control 1 INTRODUCTION Hydraulic actuation systems have been widely used due
Chen, Qingyan "Yan"
.0 for simulating airflow and contaminant transport in and around buildings," Accepted by HVAC&R Research. #121 Using CFD Capabilities of CONTAM 3.0 for Simulating Airflow and Contaminant Transport In and Around Buildings Liangzhu (Leon) Wang, W. Stuart Dols1 Qingyan Chen2 1 Indoor Air Quality and Ventilation
Chen, Qingyan "Yan"
use efficiency are three important29 indices for heating, ventilation and air-conditioning (HVAC1 Inverse Design Methods for Indoor Ventilation Systems Using1 CFD-Based Multi equilibrium and require ventilation rates of12 a space to design ventilation systems for the space
2D Axisymmetric Coupled CFD-kinetics Modeling of a Nonthermal Arc Plasma Torch for Diesel Fuel
Boyer, Edmond
1 2D Axisymmetric Coupled CFD-kinetics Modeling of a Nonthermal Arc Plasma Torch for Diesel Fuel-assisted diesel fuel reformer developed for two different applications: (i) onboard H2 production for fuel cell. In the first case, diesel fuel reacts with air while in the second case it reacts with diesel engine exhaust
Multiphase fluid characterization system
Sinha, Dipen N.
2014-09-02T23:59:59.000Z
A measurement system and method for permitting multiple independent measurements of several physical parameters of multiphase fluids flowing through pipes are described. Multiple acoustic transducers are placed in acoustic communication with or attached to the outside surface of a section of existing spool (metal pipe), typically less than 3 feet in length, for noninvasive measurements. Sound speed, sound attenuation, fluid density, fluid flow, container wall resonance characteristics, and Doppler measurements for gas volume fraction may be measured simultaneously by the system. Temperature measurements are made using a temperature sensor for oil-cut correction.
Supercritical fluid extraction
Wai, Chien M. (Moscow, ID); Laintz, Kenneth (Pullman, WA)
1994-01-01T23:59:59.000Z
A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated or lipophilic crown ether or fluorinated dithiocarbamate. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.
Iske, Armin
in Computational Fluid Dynamic Models L. Bonaventura , A. Iske, E. Miglio MOX Modellistica e Calcolo Scientifico challenging problems of high- dimensional approximation. Correspondence to: MOX Modellistica e Calcolo
Leandro B. Krott; José Rafael Bordin; Ney Marçal Barraz Jr; Marcia C. Barbosa
2015-02-11T23:59:59.000Z
We use Molecular Dynamics simulations to study how the nanopore and the fluid structures affects the dynamic, thermodynamic and structural properties of a confined anomalous fluid. The fluid is modeled using an effective pair potential derived from the ST4 atomistic model for water. This system exhibits density, structural and dynamical anomalies and the vapor-liquid and liquid-liquid critical points similar to the quantities observed in bulk water. The confinement is modeled both by smooth and structured walls. The temperatures of extremum density and diffusion for the confined fluid show a shift to lower values while the pressures move to higher amounts for both smooth and structured confinement. In the case of smooth walls, the critical points and the limit between fluid and amorphous phases show a non-monotonic change in the temperatures and pressures when the the nanopore size is increase. In the case of structured walls the pressures and temperatures of the critical points varies monotonicaly with the porous size. Our results are explained on basis of the competition between the different length scales of the fluid and the wall-fluid interaction.
Meso-scale turbulence in living fluids
Wensink, Henricus H; Heidenreich, Sebastian; Drescher, Knut; Goldstein, Raymond E; Löwen, Hartmut; Yeomans, Julia M
2012-01-01T23:59:59.000Z
Turbulence is ubiquitous, from oceanic currents to small-scale biological and quantum systems. Self-sustained turbulent motion in microbial suspensions presents an intriguing example of collective dynamical behavior amongst the simplest forms of life, and is important for fluid mixing and molecular transport on the microscale. The mathematical characterization of turbulence phenomena in active non-equilibrium fluids proves even more difficult than for conventional liquids or gases. It is not known which features of turbulent phases in living matter are universal or system-specific, or which generalizations of the Navier-Stokes equations are able to describe them adequately. Here, we combine experiments, particle simulations, and continuum theory to identify the statistical properties of self-sustained meso-scale turbulence in active systems. To study how dimensionality and boundary conditions affect collective bacterial dynamics, we measured energy spectra and structure functions in dense Bacillus subtilis su...
Semans, J.P.; Johnson, P.G.; LeBoeuf, R.F. Jr.; Kromka, J.A.; Goron, R.H.; Hay, G.D.
1991-04-30T23:59:59.000Z
This invention, a trainer mounted and housed within a mobile console, is used to teach and reinforce fluid principles to students. The system trainer has two centrifugal pumps, each driven by a corresponding two-speed electric motor. The motors are controlled by motor controllers for operating the pumps to circulate the fluid stored within a supply tank through a closed system. The pumps may be connected in series or in parallel. A number of valves are also included within the system to effect different flow paths for the fluid. In addition, temperature and pressure sensing instruments are installed throughout the closed system for measuring the characteristics of the fluid, as it passes through the different valves and pumps. These measurements are indicated on a front panel mounted to the console, as a teaching aid, to allow the students to observe the characteristics of the system.
Brenner, Howard
This paper presents a unified theory of phoretic phenomena in single-component fluids. Simple formulas are given for the phoretic velocities of small inert force-free non-Brownian particles migrating through otherwise ...
Semans, Joseph P. (Uniontown, PA); Johnson, Peter G. (Pittsburgh, PA); LeBoeuf, Jr., Robert F. (Clairton, PA); Kromka, Joseph A. (Idaho Falls, ID); Goron, Ronald H. (Connellsville, PA); Hay, George D. (Venetia, PA)
1993-01-01T23:59:59.000Z
A trainer, mounted and housed within a mobile console, is used to teach and reinforce fluid principles to students. The system trainer has two centrifugal pumps, each driven by a corresponding two-speed electric motor. The motors are controlled by motor controllers for operating the pumps to circulate the fluid stored within a supply tank through a closed system. The pumps may be connected in series or in parallel. A number of valves are also included within the system to effect different flow paths for the fluid. In addition, temperature and pressure sensing instruments are installed throughout the closed system for measuring the characteristics of the fluid, as it passes through the different valves and pumps. These measurements are indicated on a front panel mounted to the console, as a teaching aid, to allow the students to observe the characteristics of the system.
West, Phillip B. (Idaho Falls, ID)
2006-01-17T23:59:59.000Z
A method and apparatus suitable for coupling seismic or other downhole sensors to a borehole wall in high temperature and pressure environments. In one embodiment, one or more metal bellows mounted to a sensor module are inflated to clamp the sensor module within the borehole and couple an associated seismic sensor to a borehole wall. Once the sensing operation is complete, the bellows are deflated and the sensor module is unclamped by deflation of the metal bellows. In a further embodiment, a magnetic drive pump in a pump module is used to supply fluid pressure for inflating the metal bellows using borehole fluid or fluid from a reservoir. The pump includes a magnetic drive motor configured with a rotor assembly to be exposed to borehole fluid pressure including a rotatable armature for driving an impeller and an associated coil under control of electronics isolated from borehole pressure.
Circulating Fluid Bed Combustor
Fraley, L. D.; Do, L. N.; Hsiao, K. H.
1982-01-01T23:59:59.000Z
The circulating bed combustor represents an alternative concept of burning coal in fluid bed technology, which offers distinct advantages over both the current conventional fluidized bed combustion system and the pulverized coal boilers equipped...
might want to experiment with turbulence, or with fluid energy devices, like hydrogen fuel cells1 1 EXPERIMENTING WITH FLUIDS OC-569a Winter 2010 GFD lab: Ocean Sciences Bldg. Rm 107; teaching.ocean.washington.edu/research/gfd 1. INTRODUCTION For some this will be a GFD course...Geophysical Fluid Dynamics. GFD is fluid
Weakly nonlocal fluid mechanics - the Schrodinger equation
P. Van; T. Fulop
2004-06-09T23:59:59.000Z
A weakly nonlocal extension of ideal fluid dynamics is derived from the Second Law of thermodynamics. It is proved that in the reversible limit the additional pressure term can be derived from a potential. The requirement of the additivity of the specific entropy function determines the quantum potential uniquely. The relation to other known derivations of Schr\\"odinger equation (stochastic, Fisher information, exact uncertainty) is clarified.
Integrable Supersymmetric Fluid Mechanics from Superstrings
Y. Bergner; R. Jackiw
2001-05-03T23:59:59.000Z
Following the construction of a model for the planar supersymmetric Chaplygin gas, supersymmetric fluid mechanics in (1+1)-dimensions is obtained from the light-cone parametrized Nambu-Goto superstring in (2+1)-dimensions. The lineal model is completely integrable and can be formulated neatly using Riemann coordinates. Infinite towers of conserved charges and supercharges are exhibited. They form irreducible representations of a dynamical (hidden) SO(2,1) symmetry group.
Oborny, Michael C. (Albuquerque, NM); Paul, Phillip H. (Livermore, CA); Hencken, Kenneth R. (Pleasanton, CA); Frye-Mason, Gregory C. (Cedar Crest, NM); Manginell, Ronald P. (Albuquerque, NM)
2001-01-01T23:59:59.000Z
A valve for controlling fluid flows. This valve, which includes both an actuation device and a valve body provides: the ability to incorporate both the actuation device and valve into a unitary structure that can be placed onto a microchip, the ability to generate higher actuation pressures and thus control higher fluid pressures than conventional microvalves, and a device that draws only microwatts of power. An electrokinetic pump that converts electric potential to hydraulic force is used to operate, or actuate, the valve.
Molecular Dynamics Simulations of Heat Transfer In Nanoscale Liquid Films
Kim, Bo Hung
2010-07-14T23:59:59.000Z
Molecular Dynamics (MD) simulations of nano-scale flows typically utilize fixed lattice crystal interactions between the fluid and stationary wall molecules. This approach cannot properly model thermal interactions at the wall-fluid interface...
MQSN -Fluid queues Werner Scheinhardt
Boucherie, Richard J.
of Markov fluid sources is again Markov fluid. This idea can be formalized using Kronecker sums. #12;Burst information captured by number of sources that is on! #12;Burst-level models: Markov fluid Special case: sources are identical, for instance two-state on-off Markov-fluid sources. All state information captured
Lecture notes Introductory fluid mechanics
Malham, Simon J.A.
Lecture notes Introductory fluid mechanics Simon J.A. Malham Simon J.A. Malham (15th September 2014 of fluid mechanics and along the way see lots of interesting applications. 2 Fluid flow, the Continuum are generally incompressible--a feature essential to all modern car braking mechanisms. Fluids can be further
Fluorescent fluid interface position sensor
Weiss, Jonathan D.
2004-02-17T23:59:59.000Z
A new fluid interface position sensor has been developed, which is capable of optically determining the location of an interface between an upper fluid and a lower fluid, the upper fluid having a larger refractive index than a lower fluid. The sensor functions by measurement, of fluorescence excited by an optical pump beam which is confined within a fluorescent waveguide where that waveguide is in optical contact with the lower fluid, but escapes from the fluorescent waveguide where that waveguide is in optical contact with the upper fluid.
Dmitry A. Fedosov; Ankush Sengupta; Gerhard Gompper
2015-07-31T23:59:59.000Z
Janus colloids propelled by light, e.g., thermophoretic particles, offer promising prospects as artificial microswimmers. However, their swimming behavior and its dependence on fluid properties and fluid-colloid interactions remain poorly understood. Here, we investigate the behavior of a thermophoretic Janus colloid in its own temperature gradient using numerical simulations. The dissipative particle dynamics method with energy conservation is used to investigate the behavior in non-ideal and ideal-gas like fluids for different fluid-colloid interactions, boundary conditions, and temperature-controlling strategies. The fluid-colloid interactions appear to have a strong effect on the colloid behavior, since they directly affect heat exchange between the colloid surface and the fluid. The simulation results show that a reduction of the heat exchange at the fluid-colloid interface leads to an enhancement of colloid's thermophoretic mobility. The colloid behavior is found to be different in non-ideal and ideal fluids, suggesting that fluid compressibility plays a significant role. The flow field around the colloid surface is found to be dominated by a source-dipole, in agreement with the recent theoretical and simulation predictions. Finally, different temperature-control strategies do not appear to have a strong effect on the colloid's swimming velocity.
Tactic behaviors in bacterial dynamics
Sekora, Michael David
2005-01-01T23:59:59.000Z
The locomotion of a wide class of motile bacteria can be mathematically described as a biased random walk in three-dimensional space. Fluid mechanics and probability theory are invoked to model the dynamics of bacteria ...
Non-relativistic conformal symmetries in fluid mechanics
P. -M. Zhang; P. A. Horvathy
2009-10-24T23:59:59.000Z
The symmetries of a free incompressible fluid span the Galilei group, augmented with independent dilations of space and time. When the fluid is compressible, the symmetry is enlarged to the expanded Schroedinger group, which also involves, in addition, Schroedinger expansions. While incompressible fluid dynamics can be derived as an appropriate non-relativistic limit of a conformally-invariant relativistic theory, the recently discussed Conformal Galilei group, obtained by contraction from the relativistic conformal group, is not a symmetry. This is explained by the subtleties of the non-relativistic limit.
Fluid driven recipricating apparatus
Whitehead, John C. (Davis, CA)
1997-01-01T23:59:59.000Z
An apparatus comprising a pair of fluid driven pump assemblies in a back-to-back configuration to yield a bi-directional pump. Each of the pump assemblies includes a piston or diaphragm which divides a chamber therein to define a power section and a pumping section. An intake-exhaust valve is connected to each of the power sections of the pump chambers, and function to direct fluid, such as compressed air, into the power section and exhaust fluid therefrom. At least one of the pistons or diaphragms is connected by a rod assembly which is constructed to define a signal valve, whereby the intake-exhaust valve of one pump assembly is controlled by the position or location of the piston or diaphragm in the other pump assembly through the operation of the rod assembly signal valve. Each of the pumping sections of the pump assemblies are provided with intake and exhaust valves to enable filling of the pumping section with fluid and discharging fluid therefrom when a desired pressure has been reached.
Fluid driven reciprocating apparatus
Whitehead, J.C.
1997-04-01T23:59:59.000Z
An apparatus is described comprising a pair of fluid driven pump assemblies in a back-to-back configuration to yield a bi-directional pump. Each of the pump assemblies includes a piston or diaphragm which divides a chamber therein to define a power section and a pumping section. An intake-exhaust valve is connected to each of the power sections of the pump chambers, and function to direct fluid, such as compressed air, into the power section and exhaust fluid therefrom. At least one of the pistons or diaphragms is connected by a rod assembly which is constructed to define a signal valve, whereby the intake-exhaust valve of one pump assembly is controlled by the position or location of the piston or diaphragm in the other pump assembly through the operation of the rod assembly signal valve. Each of the pumping sections of the pump assemblies are provided with intake and exhaust valves to enable filling of the pumping section with fluid and discharging fluid therefrom when a desired pressure has been reached. 13 figs.
Full Life Wind Turbine Gearbox Lubricating Fluids
Lutz, Glenn A.; Jungk, Manfred; Bryant, Jonathan J.; Lauer, Rebecca S.; Chobot, Anthony; Mayer, Tyler; Palmer, Shane; Kauffman, Robert E.
2012-02-28T23:59:59.000Z
Industrial gear box lubricants typically are hydrocarbon based mineral oils with considerable amounts of additives to overcome the lack of base fluid properties like wear protection, oxidation stability, load carrying capacity, low temperature solidification and drop of viscosity at higher temperatures. For today's wind turbine gearboxes, the requirements are more severe and synthetic hydrocarbon oils are used to improve on this, but all such hydrocarbon based lubricants require significant amounts of Extreme Pressure (EP) additives to meet performance requirements. Perfluoropolyether (PFPE) fluids provide load carrying capacity as an inherent property. During the course of the project with the main tasks of 'Establish a Benchmark', 'Lubricant Evaluation', 'Full Scale Gearbox Trial' and 'Economic Evaluation', the PAO Reference oil exhibited significant changes after laboratory gear testing, in service operation in the field and full scale gearbox trial. Four hydrocarbon base oils were selected for comparison in the benchmarking exercise and showed variation with respect to meeting the requirements for the laboratory micro-pitting tests, while the PFPE fluid exceeded the requirements even with the material taken after the full scale gear box trial. This is remarkable for a lubricant without EP additives. Laboratory bearing tests performed on the PFPE fluids before and after the full scale gear box trial showed the results met requirements for the industry standard. The PFPE fluid successfully completed the full scale gear box test program which included baseline and progressive staged load testing. The evaluation of gears showed no micro-pitting or objectionable wear. By the final stage, lubricant film thickness had been reduced to just 21% of its original value, this was by design and resulted in a lambda ratio of well below 1. This test design scenario of a low lambda ratio is a very undesirable lubrication condition for real world but creates the ability to test the lubricating fluids performance under the most extreme conditions. The PAO Reference oil also passed its testing without any noticeable deterioration of the gear surface. However the PAO Reference oil was replaced midway through the progressive loading, as the lubricant was burned in an attempt to raise the sump temperature to the same levels as for the PFPE. Both materials experienced a decrease of viscosity during their respective run times. The viscosity index decreased for the PAO there while there was a slight increase for the PFPE. FZG laboratory gear tests and measurements of the drive motor's current during the full scale gear box trial were made to characterize the relative efficiency between the PFPE fluid and the PAO Reference oil. In the FZG laboratory efficiency test, the PFPE fluids show much higher churning losses due to their higher viscosity and density. The analysis seems to show that the efficiency correlates better to dynamic viscosity than any other of the measured metrics such as film thickness. In load stages where the load, speed and temperature are similar, the PFPE fluid has a greater film thickness and theoretical gear protection, but requires a larger current for the drive motor than the PAO. However in load stages where the film thickness is the same, the PFPE fluid's reduced dynamic viscosity gives it a slight efficiency advantage relative to the PAO reference oil. Ultimately, many factors such as temperature, rotational speed, and fluid viscosity combine in a complex fashion to influence the results. However, the PFPE's much lower change of viscosity with respect to temperature, allows variations in designing an optimum viscosity to balance efficiency versus gear protection. Economic analysis was done using Cost of Energy calculations. The results vary from 5.3% for a 'Likely Case' to 16.8% for a 'Best Case' scenario as potential cost improvement by using PFPE as the gearbox lubricating fluid. It is important to note the largest portion of savings comes in Levelized Replacement Cost, which is dictated by the assumption on gearb
Nonlinear finite-Larmor-radius effects in reduced fluid models
Brizard, A. J. [Department of Chemistry and Physics, Saint Michael's College, Colchester, Vermont 05439 (United States); Denton, R. E.; Rogers, B. [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States); Lotko, W. [Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States)
2008-08-15T23:59:59.000Z
The polarization magnetization effects associated with the dynamical reduction leading to the nonlinear gyrokinetic Vlasov-Maxwell equations are shown to introduce nonlinear finite-Larmor-radius (FLR) effects into a set of nonlinear reduced-fluid equations previously derived by the Lagrangian variational method [A. J. Brizard, Phys. Plasmas 12, 092302 (2005)]. These intrinsically nonlinear FLR effects, which are associated with the transformation from guiding-center phase-space dynamics to gyrocenter phase-space dynamics, are different from the standard FLR corrections associated with the transformation from particle to guiding-center phase-space dynamics. We also present the linear dispersion relation results from a nonlinear simulation code using these reduced-fluid equations. The simulation results (in both straight dipole geometries) demonstrate that the equations describe the coupled dynamics of Alfven sound waves and that the total simulation energy is conserved.
EXPERIMENTAL BUBBLE FORMATION IN A LARGE SCALE SYSTEM FOR NEWTONIAN AND NONNEWTONIAN FLUIDS
Leishear, R; Michael Restivo, M
2008-06-26T23:59:59.000Z
The complexities of bubble formation in liquids increase as the system size increases, and a photographic study is presented here to provide some insight into the dynamics of bubble formation for large systems. Air was injected at the bottom of a 28 feet tall by 30 inch diameter column. Different fluids were subjected to different air flow rates at different fluid depths. The fluids were water and non-Newtonian, Bingham plastic fluids, which have yield stresses requiring an applied force to initiate movement, or shearing, of the fluid. Tests showed that bubble formation was significantly different in the two types of fluids. In water, a field of bubbles was formed, which consisted of numerous, distributed, 1/4 to 3/8 inch diameter bubbles. In the Bingham fluid, large bubbles of 6 to 12 inches in diameter were formed, which depended on the air flow rate. This paper provides comprehensive photographic results related to bubble formation in these fluids.
Universal fluid droplet ejector
Lee, E.R.; Perl, M.L.
1999-08-24T23:59:59.000Z
A droplet generator comprises a fluid reservoir having a side wall made of glass or quartz, and an end cap made from a silicon plate. The end cap contains a micromachined aperture through which the fluid is ejected. The side wall is thermally fused to the end cap, and no adhesive is necessary. This means that the fluid only comes into contact with the side wall and the end cap, both of which are chemically inert. Amplitudes of drive pulses received by reservoir determine the horizontal displacements of droplets relative to the ejection aperture. The drive pulses are varied such that the dropper generates a two-dimensional array of vertically-falling droplets. Vertical and horizontal inter-droplet spacings may be varied in real time. Applications include droplet analysis experiments such as Millikan fractional charge searches and aerosol characterization, as well as material deposition applications. 8 figs.
Gray, Harold E. (Las Vegas, NV); McLaurin, Felder M. (Las Vegas, NV); Ortiz, Monico (Las Vegas, NV); Huth, William A. (Las Vegas, NV)
1996-01-01T23:59:59.000Z
A device or system for monitoring for the presence of leaks from a hazardous fluid is disclosed which uses two electrodes immersed in deionized water. A gas is passed through an enclosed space in which a hazardous fluid is contained. Any fumes, vapors, etc. escaping from the containment of the hazardous fluid in the enclosed space are entrained in the gas passing through the enclosed space and transported to a closed vessel containing deionized water and two electrodes partially immersed in the deionized water. The electrodes are connected in series with a power source and a signal, whereby when a sufficient number of ions enter the water from the gas being bubbled through it (indicative of a leak), the water will begin to conduct, thereby allowing current to flow through the water from one electrode to the other electrode to complete the circuit and activate the signal.
Development of an analytical model for organic-fluid fouling
Panchal, C.B.; Watkinson, A.P.
1994-10-01T23:59:59.000Z
The research goal of this project is to determine ways to effectively mitigate fouling in organic fluids: hydrocarbons and derived fluids. The fouling research focuses on the development of methodology for determining threshold conditions for fouling. Initially, fluid containing chemicals known to produce foulant is analyzed; subsequently, fouling of industrial fluids is investigated. The fouling model developed for determining the effects of physical parameters is the subject of this report. The fouling model is developed on the premise that the chemical reaction for generation of precursor can take place in the bulk fluid, in the thermal-boundary layer, or at the fluid/wall interface, depending upon the interactive effects of fluid dynamics, heat and mass transfer, and the controlling chemical reaction. In the analysis, the experimental data are examined for fouling deposition of polyperoxide produced by autoxidation of indene in kerosene. The effects of fluid and wall temperatures for two flow geometries are analyzed. The results show that the relative effects of physical parameters on the fouling rate differ for the three fouling mechanisms. Therefore, to apply the closed-flow-loop data to industrial conditions, the controlling mechanism must be identified.
Ultrasonic fluid densitometry and densitometer
Greenwood, Margaret S. (Richland, WA); Lail, Jason C. (Conover, NC)
1998-01-01T23:59:59.000Z
The present invention is an ultrasonic fluid densitometer that uses a material wedge having an acoustic impedance that is near the acoustic impedance of the fluid, specifically less than a factor of 11 greater than the acoustic impedance of the fluid. The invention also includes a wedge having at least two transducers for transmitting and receiving ultrasonic signals internally reflected within the material wedge. Density of a fluid is determined by immersing the wedge into the fluid and measuring reflection of ultrasound at the wedge-fluid interface.
Ultrasonic fluid densitometry and densitometer
Greenwood, M.S.; Lail, J.C.
1998-01-13T23:59:59.000Z
The present invention is an ultrasonic fluid densitometer that uses a material wedge having an acoustic impedance that is near the acoustic impedance of the fluid, specifically less than a factor of 11 greater than the acoustic impedance of the fluid. The invention also includes a wedge having at least two transducers for transmitting and receiving ultrasonic signals internally reflected within the material wedge. Density of a fluid is determined by immersing the wedge into the fluid and measuring reflection of ultrasound at the wedge-fluid interface. 6 figs.
TRACING FLUID SOURCES IN THE COSO GEOTHERMAL SYSTEM USING FLUID...
FLUID-INCLUSION GAS CHEMISTRY Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Proceedings: TRACING FLUID SOURCES IN THE COSO GEOTHERMAL SYSTEM USING...
Domain decomposition preconditioners for higher-order discontinuous Galerkin discretizations
Diosady, Laslo Tibor
2012-01-01T23:59:59.000Z
Aerodynamic flows involve features with a wide range of spatial and temporal scales which need to be resolved in order to accurately predict desired engineering quantities. While computational fluid dynamics (CFD) has ...
El-Sawi, A.; Haghighat, F.; Akbari, H.
2013-01-01T23:59:59.000Z
A simulation tool is developed to analyze the thermal performance of a centralized latent heat thermal energy storage system (LHTES) using computational fluid dynamics (CFD). The LHTES system is integrated with a mechanical ventilation system...
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...
Unsteady adjoint analysis for output sensitivity and mesh adaptation
Krakos, Joshua Ambre
2012-01-01T23:59:59.000Z
Adjoint analysis in computational fluid dynamics (CFD) has been applied to design optimization and mesh adaptation, but due to the relative expense of unsteady analysis these applications have predominantly been for steady ...
Available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/ijhydene
Van Zee, John W.
by Elsevier Ltd. All rights reserved. 1. Introduction An ideal flow-field design in a polymer electrolyte t Computational fluid dynamics (CFD) simulations were performed for four 10Àcm2 serpentine flow-fields with single
Wang, D.; Shan, S.; Wang, R.
2006-01-01T23:59:59.000Z
presented a mathematic model for a cylindrical water tank with a cylindrical condenser as its heat source. The computational fluid dynamics (CFD) software package, FLUENT, was used to study hot water temperature distribution in the tank of the ASHPWH...
Effects of physical and chemical pretreatments on the crystallinity of bagasse
Jones, Maxine Janette
2009-05-15T23:59:59.000Z
in biomass digestibility when hydrodynamic cavitation was utilized as a pretreatment step. This previous work was expanded by studying both acoustic and hydrodynamic cavitation. Computational fluid dynamics (CFD) was used to model the cavitator to improve...
Lee, Tonghun
and gaseousfuels derivedfrom biomass arebeing researchedfor use in the transportation sector.3 These fuels include time when incor- porated into computational fluid dynamics (CFD) models. The multi-step model presented
Numerical and Experimental Investigation of Tidal Current Energy Extraction
Sun, Xiaojing
2008-01-01T23:59:59.000Z
Numerical and experimental investigations of tidal current energy extraction have been conducted in this study. A laboratory-scale water flume was simulated using commercial computational fluid dynamics (CFD) code FLUENT. ...
CX-004511: Categorical Exclusion Determination
Broader source: Energy.gov [DOE]
Displacement and Mixing in Subsea Jumpers Experimental Data and Computational Fluid Dynamics (CFD)CX(s) Applied: A9, A11Date: 11/22/2010Location(s): Tulsa, OklahomaOffice(s): Fossil Energy, National Energy Technology Laboratory
Steinhaus, Thomas
2010-01-01T23:59:59.000Z
Computational Fluid Dynamics (CFD) codes are being increasingly used in the field of fire safety engineering. They provide, amongst other things, velocity, species and heat flux distributions throughout the computational ...
Barter, Garrett Ehud
The accurate simulation of supersonic and hypersonic flows is well suited to higher-order (p > 1), adaptive computational fluid dynamics (CFD). Since these cases involve flow velocities greater than the speed of sound, an ...
Barter, Garrett E. (Garrett Ehud), 1979-
2008-01-01T23:59:59.000Z
The accurate simulation of supersonic and hypersonic flows is well suited to higher-order (p > 1), adaptive computational fluid dynamics (CFD). Since these cases involve flow velocities greater than the speed of sound, an ...
MEASUREMENT OF INTERFACIAL TENSION IN FLUID-FLUID SYSTEMS
Loh, Watson
MEASUREMENT OF INTERFACIAL TENSION IN FLUID-FLUID SYSTEMS J. Drelich Ch. Fang C.L. White Michigan been used to measure interfacial tensions between immisci- ble fluid phases. A recent monograph sources of information on the in- terfacial tension measurement methods include selected chapters in Refs
Magnetically stimulated fluid flow patterns
Martin, Jim; Solis, Kyle
2014-03-06T23:59:59.000Z
Sandia National Laboratories' Jim Martin and Kyle Solis explain research on the effects of magnetic fields on fluid flows and how they stimulate vigorous flows. Fluid flow is a necessary phenomenon in everything from reactors to cooling engines in cars.
Magnetically stimulated fluid flow patterns
Martin, Jim; Solis, Kyle
2014-08-06T23:59:59.000Z
Sandia National Laboratories' Jim Martin and Kyle Solis explain research on the effects of magnetic fields on fluid flows and how they stimulate vigorous flows. Fluid flow is a necessary phenomenon in everything from reactors to cooling engines in cars.
Li, X.; Li, N.; Fang, F.; Zhao, D.
2006-01-01T23:59:59.000Z
computational fluid dynamics (CFD) program,and full-scale experiments were conducted to validate the calculation results in May 2005. The results show that the CFD- predicted results in the plenum were in good agreement with the measured results. Two main...
Wind power resource assessment in complex urban environments
Wind power resource assessment in complex urban environments: MIT campus case-study using CFD in Computational Fluid Dynamics (CFD) methods holds potential for the advancement of wind energy resource assessment in complex urban terrain by modeling wind circulation around urban obstacles. The geometry
-production of biomass for biofuels and alternative fuel research. #12;Annotating Plague with Proteogenomics Strains Lung Imaging Research Gets Second Wind Scientists use computational fluid dynamics (CFD, but researchers at PNNL took an important step by making the first-ever comparison between CFD- predicted
Li, X.; Li, N.; Fang, F.; Zhao, D.
2006-01-01T23:59:59.000Z
computational fluid dynamics (CFD) program,and full-scale experiments were conducted to validate the calculation results in May 2005. The results show that the CFD- predicted results in the plenum were in good agreement with the measured results. Two main...
An Application of Graph Based Evolutionary Algorithms for Diversity Preservation
Ashlock, Dan
to a thermal systems engineering design problem - the design of a biomass cook stove currently in use in Central America. Fitness evaluation involves the use of computational fluid dynamics(CFD) modeling machine yielding a large, fixed per- formance increase. Second, the resolution of the mesh for CFD
The effects of obstacle geometry on jet mixing in releases of silane
Sposato, Christina F
2000-01-01T23:59:59.000Z
Releases of silane into air and the effects of obstacles were modeled with the Computational Fluid Dynamics (CFD) code, FLUENT. First the CFD code simulated the release of a free turbulent jet of silane into air to assure that the code agreed...
Facility Siting and Layout Optimization Based on Process Safety
Jung, Seungho
2012-02-14T23:59:59.000Z
-computational fluid dynamics (CFD) was used to compare the difference between the initial layout and the final layout in order to see how obstacles and separation distances affect the dispersion or overpressures of affected facilities. One of the CFD programs, ANSYS...
Computer Vision in Fluid Mechanics
Aminfar, AmirHessam
2015-01-01T23:59:59.000Z
Laminar flows are usually unidirectional flows, which the fluidlaminar flows ? Streak line: Streak line is locus of fluid
Method and apparatus for controlling fluid flow
Miller, J.R.
1980-06-27T23:59:59.000Z
A method and apparatus for precisely controlling the rate (and hence amount) of fluid flow are given. The controlled flow rate is finely adjustable, can be extremely small (on the order of microliter-atmospheres per second), can be adjusted to zero (flow stopped), and is stable to better than 1% with time. The dead volume of the valve can be made arbitrarily small, in fact essentially zero. The valve employs no wearing mechanical parts (including springs, stems, or seals). The valve is finely adjustable, has a flow rate dynamic range of many decades, can be made compatible with any fluid, and is suitable for incorporation into an open or closed loop servo-control system.
Transport in non-conformal holographic fluids
Shailesh Kulkarni; Bum-Hoon Lee; Jae-Hyuk Oh; Chanyong Park; Raju Roychowdhury
2013-03-06T23:59:59.000Z
We have considered non-conformal fluid dynamics whose gravity dual is a certain Einstein dilaton system with Liouville type dilaton potential, characterized by an intrinsic parameter $\\eta$. We have discussed the Hawking-Page transition in this framework using hard-wall model and it turns out that the critical temperature of the Hawking-Page transition encapsulates a non-trivial dependence on $\\eta$. We also obtained transport coefficients such as AC conductivity, shear viscosity and diffusion constant in the hydrodynamic limit, which show non-trivial $\\eta$ dependent deviations from those in conformal fluids, although the ratio of the shear viscosity to entropy density is found to saturate the universal bound. Some of the retarded correlators are also computed in the high frequency limit for case study.
Breault, Ronald W, [U.S. DOE; Huckaby, Ernest D. [U.S. DOE; Shadle, Lawrence J [U.S. DOE; Spenik, James L. [REM Engineering PLLC
2013-01-01T23:59:59.000Z
The National Energy Technology Laboratory is investigating a new process for CO{sub 2} capture from large sources such as utility power generation facilities as an alternative to liquid amine based absorption processes. Many, but not all of these advanced dry processes are based upon sorbents composed of supported polyamines. In this analysis, experiments have been conducted in a small facility at different temperatures and compared to CFD reactor predictions using kinetics obtained from TGA tests. This particular investigation compares the predicted performance and the experimental performance of one of these new class of sorbents in a fluidized bed reactor. In the experiment, the sorbent absorbs CO{sub 2} from simulated flue gas in a riser reactor, separates the carbonated particles from the de-carbonated flue gas in a cyclone and then regenerates the sorbent, creating a concentrated stream of pure CO{sub 2} for sequestration. In this work, experimental measurements of adsorption are compared to predictions from a 3-dimensional non-isothermal reacting multiphase flow model. The effects of the gas flow rate and reactor temperature are explored. It is shown that the time duration for CO{sub 2} adsorption decreased for an increase in the gas flow. The details of the experimental facility and the model as well as the comparative analysis between the data and the simulation results are discussed.
Mathematical thermodynamics of fluids Eduard Feireisl
KrejcÃ, Pavel
Mathematical thermodynamics of fluids Eduard Feireisl Institute of Mathematics, Academy of Sciences Agreement 320078 CIME courses, Cetraro 29 June - 4 July 2015 Eduard Feireisl Thermodynamics of fluids #12 Thermodynamics of fluids #12;Fluids at equilibrium Thermodynamic state variables mass density
Acoustic concentration of particles in fluid flow
Ward, Michael D. (Los Alamos, NM); Kaduchak, Gregory (Los Alamos, NM)
2010-11-23T23:59:59.000Z
An apparatus for acoustic concentration of particles in a fluid flow includes a substantially acoustically transparent membrane and a vibration generator that define a fluid flow path therebetween. The fluid flow path is in fluid communication with a fluid source and a fluid outlet and the vibration generator is disposed adjacent the fluid flow path and is capable of producing an acoustic field in the fluid flow path. The acoustic field produces at least one pressure minima in the fluid flow path at a predetermined location within the fluid flow path and forces predetermined particles in the fluid flow path to the at least one pressure minima.
Oscillating fluid power generator
Morris, David C
2014-02-25T23:59:59.000Z
A system and method for harvesting the kinetic energy of a fluid flow for power generation with a vertically oriented, aerodynamic wing structure comprising one or more airfoil elements pivotably attached to a mast. When activated by the moving fluid stream, the wing structure oscillates back and forth, generating lift first in one direction then in the opposite direction. This oscillating movement is converted to unidirectional rotational movement in order to provide motive power to an electricity generator. Unlike other oscillating devices, this device is designed to harvest the maximum aerodynamic lift forces available for a given oscillation cycle. Because the system is not subjected to the same intense forces and stresses as turbine systems, it can be constructed less expensively, reducing the cost of electricity generation. The system can be grouped in more compact clusters, be less evident in the landscape, and present reduced risk to avian species.
Galilean relativistic fluid mechanics
Ván, Péter
2015-01-01T23:59:59.000Z
Single component Galilean-relativistic (nonrelativistic) fluids are treated independently of reference frames. The basic fields are given, their balances, thermodynamic relations and the entropy production is calculated. The usual relative basic fields, the mass, momentum and energy densities, the diffusion current density, the pressure tensor and the heat flux are the time- and spacelike components of the third order mass-momentum-energy density tensor according to a velocity field. The transformation rules of the basic fields are derived and prove that the non-equilibrium thermodynamic background theory, that is the Gibbs relation, extensivity condition and the entropy production is absolute, that is independent of the reference frame and also of the fluid velocity. --- Az egykomponensu Galilei-relativisztikus (azaz nemrelativisztikus) disszipativ folyadekokat vonatkoztatasi rendszertol fuggetlenul targyaljuk. Megadjuk az alapmennyisegeket, ezek merlegeit, a termodinamikai osszefuggeseket es kiszamoljuk az ...
Coalescence of bubbles and drops in an outer fluid
Joseph D. Paulsen; Rémi Carmigniani; Anerudh Kannan; Justin C. Burton; Sidney R. Nagel
2014-07-24T23:59:59.000Z
When two liquid drops touch, a microscopic connecting liquid bridge forms and rapidly grows as the two drops merge into one. Whereas coalescence has been thoroughly studied when drops coalesce in vacuum or air, many important situations involve coalescence in a dense surrounding fluid, such as oil coalescence in brine. Here we study the merging of gas bubbles and liquid drops in an external fluid. Our data indicate that the flows occur over much larger length scales in the outer fluid than inside the drops themselves. Thus we find that the asymptotic early regime is always dominated by the viscosity of the drops, independent of the external fluid. A phase diagram showing the crossovers into the different possible late-time dynamics identifies a dimensionless number that signifies when the external viscosity can be important.
Fluid bed material transfer method
Pinske, Jr., Edward E. (Akron, OH)
1994-01-01T23:59:59.000Z
A fluidized bed apparatus comprising a pair of separated fluid bed enclosures, each enclosing a fluid bed carried on an air distributor plate supplied with fluidizing air from below the plate. At least one equalizing duct extending through sidewalls of both fluid bed enclosures and flexibly engaged therewith to communicate the fluid beds with each other. The equalizing duct being surrounded by insulation which is in turn encased by an outer duct having expansion means and being fixed between the sidewalls of the fluid bed enclosures.
Supercritical Fluid Extraction
Johnston, K. P.; Flarsheim, W. M.
1984-01-01T23:59:59.000Z
changes in the solvent density and thus its dissolving power. In comparison with conventional processes, SFE offers considerable flexibility for an extractive separation using the variables of pressure, temperature, choice of solvent, and additives... or vacuum processing stages. 5. While the density, and thus the solvent capacity, of a supercritical fluid is nearly comparable to that of a liquid, the lower viscosity and higher diffusivity provide advantages in transport rates. For example...
V. Folomeev; V. Gurovich
2007-10-15T23:59:59.000Z
The unified dark energy and dark matter model within the framework of a model of a continuous medium with bulk viscosity (dark fluid) is considered. It is supposed that the bulk viscosity coefficient is an arbitrary function of the Hubble parameter. The choice of this function is carried out under the requirement to satisfy the observational data from recombination ($z\\approx 1000$) till present time.
Numerical modeling of heat transfer and fluid flow in rotor-stator cavities with throughflow
Boyer, Edmond
Numerical modeling of heat transfer and fluid flow in rotor-stator cavities with throughflow S modeling of the turbulent flow in a rotor-stator cavity subjected to a superimposed throughflow with heat the dynamical effects from the heat transfer process. The fluid flow in an enclosed disk system with axial
Lyapunov instability of rough hard-disk fluids Jacobus A. van Meel*
Posch, Harald A.
Lyapunov instability of rough hard-disk fluids Jacobus A. van Meel* FOM Institute for Atomic The dynamical instability of rough hard-disk fluids in two dimensions is characterized through the Lyapunov, measured by the maximum Lyapunov exponent, is only enhanced by the rotational degrees of freedom for high
Encapsulated Nanoparticle Synthesis and Characterization for Improved Storage Fluids: Preprint
Glatzmaier, G. C.; Pradhan, S.; Kang, J.; Curtis, C.; Blake, D.
2010-10-01T23:59:59.000Z
Nanoparticles are typically composed of 50--500 atoms and exhibit properties that are significantly different from the properties of larger, macroscale particles that have the same composition. The addition of these particles to traditional fluids may improve the fluids' thermophysical properties. As an example, the addition of a nanoparticle or set of nanoparticles to a storage fluid may double its heat capacity. This increase in heat capacity would allow a sensible thermal energy storage system to store the same amount of thermal energy in half the amount of storage fluid. The benefit is lower costs for the storage fluid and the storage tanks, resulting in lower-cost electricity. The goal of this long-term research is to create a new class of fluids that enable concentrating solar power plants to operate with greater efficiency and lower electricity costs. Initial research on this topic developed molecular dynamic models that predicted the energy states and transition temperatures for these particles. Recent research has extended the modeling work, along with initiating the synthesis and characterization of bare metal nanoparticles and metal nanoparticles that are encapsulated with inert silica coatings. These particles possess properties that make them excellent candidates for enhancing the heat capacity of storage fluids.
Downhole Fluid Analyzer Development
Bill Turner
2006-11-28T23:59:59.000Z
A novel fiber optic downhole fluid analyzer has been developed for operation in production wells. This device will allow real-time determination of the oil, gas and water fractions of fluids from different zones in a multizone or multilateral completion environment. The device uses near infrared spectroscopy and induced fluorescence measurement to unambiguously determine the oil, water and gas concentrations at all but the highest water cuts. The only downhole components of the system are the fiber optic cable and windows. All of the active components--light sources, sensors, detection electronics and software--will be located at the surface, and will be able to operate multiple downhole probes. Laboratory testing has demonstrated that the sensor can accurately determine oil, water and gas fractions with a less than 5 percent standard error. Once installed in an intelligent completion, this sensor will give the operating company timely information about the fluids arising from various zones or multilaterals in a complex completion pattern, allowing informed decisions to be made on controlling production. The research and development tasks are discussed along with a market analysis.
FINAL REPORT INI programme "Mathematics for the Fluid Earth", OctoberDecember 2013
FINAL REPORT INI programme "Mathematics for the Fluid Earth", OctoberDecember 2013 Organisers: M the behavior of atmosphere and ocean dynamics. This programme followed on from a very large programme at INI
Tirtaatmadja, Viyada
2007-01-23T23:59:59.000Z
The dynamics of drop formation and pinch-off have been investigated for a series of low viscosity elastic fluids possessing similar shear viscosities, but differing substantially in elastic properties. On initial approach ...