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Equation Solver (equation + solver)

Distribution by Scientific Domains

Engineering	66%
Earth and Environmental Science	13%

Kinds of Equation Solver

differential equation solver

Selected Abstracts

Performance improvements for olive oil refining plants

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 6 2010
Elif Bozoglan
Abstract The main objective of this study, which is conducted for the first time to the best of the authors' knowledge, is to identify improvements in olive oil refinery plants' performance. In the analyses, the actual operational data are used for performance assessment purposes. The refinery plant investigated is located in Izmir Turkey and has an oil capacity of 6250,kg,h,1. It basically incorporates steam generators, several tanks, heat exchangers, a distillation column, flash tanks and several pumps. The values for exergy efficiency and exergy destruction of operating components are determined based on a reference (dead state) temperature of 25°C. An Engineering Equation Solver (EES) software program is utilized to do the analyses of the plant. The exergy transports between the components and the consumptions in each of the components of the whole plant are determined for the average parameters obtained from the actual data. The exergy loss and flow diagram (the so-called Grassmann diagram) are also presented for the entire plant studied to give quantitative information regarding the proportion of the exergy input that is dissipated in the various plant components. Among the observed components in the plant, the most efficient equipment is found to be the shell- and tube-type heat exchanger with an exergy efficiency value of 85%. The overall exergetic efficiency performance of the plant (the so-called functional exergy efficiency) is obtained to be about 12%, while the exergy efficiency value on the exergetic fuel,product basis is calculated to be about 65%. Copyright © 2009 John Wiley & Sons, Ltd. [source]

A mixed finite element solver for liquid,liquid impacts

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 8 2004
Enrico Bertolazzi
Abstract The impact of a liquid column on a liquid surface initially at rest is numerically modelled to describe air entrapment and bubble formation processes. The global quantities of interest are evaluated in the framework of the potential theory. The numerical method couples a potential flow solver based on a Mixed Finite Element Method with an Ordinary Differential Equation solver discretized by the Crank,Nicholson scheme. The capability of the method in solving liquid,liquid impacts is illustrated in two numerical experiments taken from literature and a good agreement with the literature data is obtained. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Magnetostatic analysis of a brushless DC motor using a two-dimensional partial differential equation solver

COMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 2 2001
A. Kostaridis
Abstract A finite element, magnetostatic analysis, of a brushless direct current motor containing non-linear materials and permanent magnets is presented. The analysis is performed with PDEaseÔ, a low cost, two-dimensional partial differential equation solver. The descriptor file is remarkably short and easy to understand, enabling students to focus on the application and not on the finite element method. © 2001 John Wiley & Sons, Inc. Comput Appl Eng Educ 9: 93,100, 2001 [source]

Integration of General Sparse Matrix and Parallel Computing Technologies for Large,Scale Structural Analysis

COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 6 2002
Hsien Hsieh, Shang
Both general sparse matrix and parallel computing technologies are integrated in this study as a finite element solution of large,scale structural problems in a PC cluster environment. The general sparse matrix technique is first employed to reduce execution time and storage requirements for solving the simultaneous equilibrium equations in finite element analysis. To further reduce the time required for large,scale structural analyses, two parallel processing approaches for sharing computational workloads among collaborating processors are then investigated. One approach adopts a publicly available parallel equation solver, called SPOOLES, to directly solve the sparse finite element equations, while the other employs a parallel substructure method for the finite element solution. This work focuses more on integrating the general sparse matrix technique and the parallel substructure method for large,scale finite element solutions. Additionally, numerical studies have been conducted on several large,scale structural analyses using a PC cluster to investigate the effectiveness of the general sparse matrix and parallel computing technologies in reducing time and storage requirements in large,scale finite element structural analyses. [source]

Optimization Study of ICRF Heating in the LHD and HSX Configurations

CONTRIBUTIONS TO PLASMA PHYSICS, Issue 6-7 2010
S. Murakami
Abstract Two global simulation codes, TASK/WM (a full wave solver) and GNET (a 5-D drift kinetic equation solver), are combined to simulate the ICRF heating in the 3D magnetic configuration. The combined code is applied to the ICRF minority heating in the LHD configuration. An optimization of the ICRF heating is considered in changing the magnetic configurations and the resonance surfaces in the LHD plasmas using GNET code. It is found that the heating efficiency is improved about 30% with the heating power of 10MW in the optimized heating scenario from that of the present standard off-axis heating scenario. Also the ICRF minority heating is studied in the HSX plasma and it is found that the ICRF heating of about 100kW is still effective to heat the plasma even , /a , 1/7.5 for tail ions (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

2-D/3-D multiply transmitted, converted and reflected arrivals in complex layered media with the modified shortest path method

GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2009
Chao-Ying Bai
SUMMARY Grid-cell based schemes for tracing seismic arrivals, such as the finite difference eikonal equation solver or the shortest path method (SPM), are conventionally confined to locating first arrivals only. However, later arrivals are numerous and sometimes of greater amplitude than the first arrivals, making them valuable information, with the potential to be used for precise earthquake location, high-resolution seismic tomography, real-time automatic onset picking and identification of multiple events on seismic exploration data. The purpose of this study is to introduce a modified SPM (MSPM) for tracking multiple arrivals comprising any kind of combination of transmissions, conversions and reflections in complex 2-D/3-D layered media. A practical approach known as the multistage scheme is incorporated into the MSPM to propagate seismic wave fronts from one interface (or subsurface structure for 3-D application) to the next. By treating each layer that the wave front enters as an independent computational domain, one obtains a transmitted and/or converted branch of later arrivals by reinitializing it in the adjacent layer, and a reflected and/or converted branch of later arrivals by reinitializing it in the incident layer. A simple local grid refinement scheme at the layer interface is used to maintain the same accuracy as in the one-stage MSPM application in tracing first arrivals. Benchmark tests against the multistage fast marching method are undertaken to assess the solution accuracy and the computational efficiency. Several examples are presented that demonstrate the viability of the multistage MSPM in highly complex layered media. Even in the presence of velocity variations, such as the Marmousi model, or interfaces exhibiting a relatively high curvature, later arrivals composed of any combination of the transmitted, converted and reflected events are tracked accurately. This is because the multistage MSPM retains the desirable properties of a single-stage MSPM: high computational efficiency and a high accuracy compared with the multistage FMM scheme. [source]

Molecular mechanics in the context of the finite element method

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 7 2009
Jens Wackerfuß
Abstract In molecular mechanics, the formalism of the finite element method can be exploited in order to analyze the behavior of atomic structures in a computationally efficient way. Based on the atom-related consideration of the atomic interactions, a direct correlation between the type of the underlying interatomic potential and the design of the related finite element is established. Each type of potential is represented by a specific finite element. A general formulation that unifies the various finite elements is proposed. Arbitrary diagonal- and cross-terms dependent on bond length, valence angle, dihedral angle, improper dihedral angle and inversion angle can also be considered. The finite elements are formulated in a geometrically exact setting; the related formulas are stated in detail. The mesh generation can be performed using well-known procedures typically used in molecular dynamics. Although adjacent elements overlap, a double counting of the element contributions (as a result of the assembly process) cannot occur a priori. As a consequence, the assembly process can be performed efficiently line by line. The presented formulation can easily be implemented in standard finite element codes; thus, already existing features (e.g. equation solver, visualization of the numerical results) can be employed. The formulation is applied to various interatomic potentials that are frequently used to describe the mechanical behavior of carbon nanotubes. The effectiveness and robustness of this method are demonstrated by means of several numerical examples. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Application of exergy analysis to various psychrometric processes

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 12 2003
Bilal A. Qureshi
Abstract The relation between work and changes in entropy generation arises from the simultaneous treatment of the first and second laws referred to as exergy (or available energy) analysis. In this paper, we discuss thermodynamic analysis of various psychrometric processes using the concept of exergy. A parametric study of each of the processes is carried out to determine the variation of second-law efficiency as a function of mass flow rate, relative humidity and temperature. Other trends such as variation of temperature with relative humidity are also shown where applicable. Irreversible losses are calculated by applying an exergy balance on each system. In this regard, an engineering equation solver (EES) programme is used, which is unique because it has built-in functions for most thermodynamic and transport properties; removing the need for approximate equations. The concept of total exergy as the sum of thermomechanical and chemical parts is employed in calculating the flow exergies for air and water vapor mixtures. It is shown for some processes investigated that an increase in the relative humidity of the incoming air stream increases second-law efficiency. We notice that a decrease in mass flow rate of fresh air (second incoming stream) in the case of adiabatic mixing decreases the second-law efficiency of the process. Also, it is shown that the mass flow rate (of both water and steam) has almost a linear relationship with relative humidity in the range investigated. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Numerical nonlinear observers using pseudo-Newton-type solvers

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 17 2008
Shigeru HanbaArticle first published online: 12 DEC 200
Abstract In constructing a globally convergent numerical nonlinear observer of Newton-type for a continuous-time nonlinear system, a globally convergent nonlinear equation solver with a guaranteed rate of convergence is necessary. In particular, the solver should be Jacobian free, because an analytic form of the state transition map of the nonlinear system is generally unavailable. In this paper, two Jacobian-free nonlinear equation solvers of pseudo-Newton type that fulfill these requirements are proposed. One of them is based on the finite difference approximation of the Jacobian with variable step size together with the line search. The other uses a similar idea, but the estimate of the Jacobian is mostly updated through a BFGS-type law. Then, by using these solvers, globally stable numerical nonlinear observers are constructed. Numerical results are included to illustrate the effectiveness of the proposed methods. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Ohmic heating of dairy fluids,effects of local electric field on temperature distribution

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009
Heng Jin Tham
Abstract This paper presents the heat transfer model of a continuous flow ohmic heating process. The model fluid used was a mixture of reconstituted skimmed milk and whey protein concentrate solution. Two-dimensional numerical simulations of an annular ohmic heater were performed using a general purpose partial differential equation solver, FlexPDE. The momentum, energy, and electrical equations were solved for a laminar flow regime. Two models were used to determine the volumetric heating rate, one taking into account the local electric field by solving the Laplace equation while another model assumes an average voltage gradient applied between the two electrodes. Results show that while the wall temperature distribution is different for the two cases, the bulk fluid temperature and the average outlet temperature are the same. The predicted temperatures generally agree well with the measured temperatures. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source]

Grid services for earthquake science

CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 6-7 2002
Geoffrey Fox
Abstract We describe an information system architecture for the ACES (Asia,Pacific Cooperation for Earthquake Simulation) community. It addresses several key features of the field,simulations at multiple scales that need to be coupled together; real-time and archival observational data, which needs to be analyzed for patterns and linked to the simulations; a variety of important algorithms including partial differential equation solvers, particle dynamics, signal processing and data analysis; a natural three-dimensional space (plus time) setting for both visualization and observations; the linkage of field to real-time events both as an aid to crisis management and to scientific discovery. We also address the need to support education and research for a field whose computational sophistication is rapidly increasing and spans a broad range. The information system assumes that all significant data is defined by an XML layer which could be virtual, but whose existence ensures that all data is object-based and can be accessed and searched in this form. The various capabilities needed by ACES are defined as grid services, which are conformant with emerging standards and implemented with different levels of fidelity and performance appropriate to the application. Grid Services can be composed in a hierarchical fashion to address complex problems. The real-time needs of the field are addressed by high-performance implementation of data transfer and simulation services. Further, the environment is linked to real-time collaboration to support interactions between scientists in geographically distant locations. Copyright © 2002 John Wiley & Sons, Ltd. [source]

A Green's function-based method for the transient analysis of plane waves obliquely incident on lossy and dispersive planar layers

INTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 6 2008
Giulio Antonini
Abstract This paper presents a new methodology for the transient analysis of plane waves obliquely incident on a planar lossy and dispersive layer. The proposed model is based on the Sturm,Liouville problem associated with the propagation equations. Green's function is calculated in a series form and the open-end impedance matrix is obtained as the sum of infinite rational functions. This form permits an easy identification of poles and residues. Furthermore, the knowledge of poles leads to the development of a model order reduction technique by selecting only the dominant poles of the system. The pole,residue representation is converted into a state-space model that can be easily interfaced with ordinary differential equation solvers. The numerical results confirm the effectiveness of the proposed modeling technique. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Numerical nonlinear observers using pseudo-Newton-type solvers

A new fast stratospheric ozone chemistry scheme in an intermediate general-circulation model.

THE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 610 2005
I: Description, evaluation
Abstract Simulation of future climate-composition changes requires simulations of coupled dynamical-radiative-chemical models of many decades in length. Yet, to assure the generality of the simulation's results against uncertainties in emissions, unforced year-to-year variability and dependence on initial conditions, it is necessary to repeat them a significant number of times. The computational cost of such an exercise is still too large when using complex three-dimensional coupled models. We introduce in this paper a computationally efficient chemical scheme, the FAst STratospheric Ozone Chemistry (FASTOC) scheme, which has advantages over many existing fast methods, as it does not rely on relaxation to assumed conditions, does not rely on tuning parameters, and does not rely on linearization approximations. The scheme is nevertheless three orders of magnitude faster than a stiff kinetic equations solver. Part I of the paper gives a detailed description of the FASTOC model and some performance evaluations when incorporated in a general-circulation model (GCM). In Part II, the FASTOC model, coupled to a GCM, is specifically applied to study the impact of climate,chemistry interactions on stratospheric ozone in the middle of the twenty-first century. Copyright © 2005 Royal Meteorological Society [source]