bluuebunny/crossref_metadata_2025_split huggingface dataset:
Catalytic Adsorptive Stripping Voltammetry of Cobalt in the Presence of Dimethylglyoxime and Nitrite at In Situ Plated Lead–Copper Film Electrode
Authors: Grabarczyk Malgorzata , Tyszczuk Katarzyna , Korolczuk Mieczyslaw 
Published: November 2005

AbstractA lead‐copper film electrode was proposed for Co(II) determination by catalytic adsorptive stripping voltammetry. The electrode was plated in situ and hence the exchange of a solution after plating step was not required. At optimized conditions the calibration graph for Co(II) was linear from 5×10−10 to 2×10−8 mol L−1 for accumulation time of 15 s. The relative standard deviation for Co(II) determination at concentration 5×10−9 mol L−1 was 4.1%. The detection limits for Co(II) were 1.2×10−10 and 1.0×10−11 mol L−1 for an accumulation time of 15 and 180 s, respectively. The method was applied to Co(II) determination in certified reference material and other water samples.
Finite volume multigrid prediction of laminar natural convection: Bench‐mark solutions
Authors: Hortmann M. , Perić M. , Scheuerer G. 
Published: November 2005

AbstractA finite volume multigrid procedure for the prediction of laminar natural convection flows is presented, enabling efficient and accurate calculations on very fine grids. The method is fully conservative and uses second‐order central differencing for convection and diffusion fluxes. The calculations start on a coarse (typically 10 × 10 control volumes) grid and proceed to finer grids until the desired accuracy or maximum affordable storage is reached. The computing times increase thereby linearly with the number of control volumes.Solutions are presented for the flow in a closed cavity with side walls at different temperatures and insulated top and bottom walls. Rayleigh numbers of 104, 105 and 106 are considered. Grids as fine as 640 × 640 control volumes are used and the results are believed to be accurate to within 0–01%. Second‐order monotonic convergence to grid‐independent values is observed for all predicted quantities.
Interactive vortex shedding from a pair of circular cylinders in a transverse arrangement
Authors: Chang Keun‐Shik , Song Chang‐Joon 
Published: November 2005

AbstractInteractive vortex shedding in the multiply connected domain formed by a pair of circular cylinders is analysed by the FEM–FDM blending technique. The vorticity–streamfunction formulation is used to solve the incompressible Navier–Stokes equations at Re = 100, with the time‐dependent wall streamfunctions determined from the pressure constraint condition and the far‐field streamfunctions from the integral series formula developed earlier by the authors. The standard Galerkin finite element method is used in the relatively small FEM subdomain and the finite difference method based on the general co‐ordinate system in the rest of the flow domain. Symmetric, antisymmetric and asymmetric wake patterns are obtained confirming the earlier experimental findings. The bistable nature of the asymmetric vortex shedding as well as the intermittent drifting from one status to the other between symmetric and antisymmetric wake patterns are reported.
Finite element analysis of creeping flows using marker particles
Authors: Shiojima Takeo , Shimazaki Yoji , Daiguji Hisaaki 
Published: November 2005

AbstractThe penalty function formulation of the finite element method is described for the analysis of transient incompressible creeping flows. Marker particles are utilized to represent moving free surfaces and to visualize the flow patterns. For determining the movement of markers from element to element, the area coordinate system of the linear triangular element is introduced.With the method presented, a punch indentation problem and an injection problem for an L‐shaped cavity are solved for Newtonian and power‐law fluids.
Two‐dimensional sloshing analysis by Lagrangian finite element method
Authors: Okamoto Takashi , Kawahara Mutsuto 
Published: November 2005

AbstractTwo dimensional sloshing analysis has been carried out by the Lagrangian finite element method. For the integration in time, the velocity correction method with the same interpolation functions for velocity and pressure is successfully used. The Lagrangian treatment to pursue the free surface position is presented. The comparison with the experiments shows extremely good agreement. It is shown that the large amplitude sloshing waves in a container can be analyzed by the present method.
A fractional‐step Taylor–Galerkin method for unsteady incompressible flows
Authors: Laval H. , Quartapelle L. 
Published: November 2005

AbstractThis paper describes the application of the Taylor–Galerkin method to the calculation of incompressible viscous flows. A finite element fractional‐step method for the Navier–Stokes equations is combined with the Taylor–Galerkin method to achieve an accurate treatment of the convection part of the problem. A scheme of second‐order accuracy in time for the non‐linear convection written in non‐conservative form is presented. Numerical results are provided to illustrate the quality of the computed transient solutions in two dimensions.
Simulation of turbulence with transient mean
Authors: Bègue C. , Cardot B. , Parès C. , Pironneau O. 
Published: November 2005

AbstractIn general the κ–ε turbulence model is used for stationary turbulent mean flow. First we review some of the hypotheses for the derivation of the model. Then we study it from the point of view of the numerical analyst (positivity of κ and ε, boundedness, etc.). Finally we analyse an extension called MPP, specially derived for transient mean flow. The rest of the paper is devoted to a robust (stable) numerical implementation of these models and several tests for the flow behind a cylinder.
Upwind adaptive finite element investigations of the two‐dimensional reactive interaction of supersonic gaseous jets
Authors: Chargy D. , Dervieux A. , Larrouturou B. 
Published: November 2005

AbstractWe describe an upwind finite element method aimed at numerically simulating the two‐dimensional transonic flow of a reactive gaseous mixture. The method uses in particular a triangular finite element mesh, with an adaptive procedure based on mesh refinement by triangle division, and an upwind non‐oscillatory scheme based on an approximate Riemann solver for the evaluation of the convective terms for all species. Results concerning the reactive interaction of two supersonic gaseous jets are presented.
Multiple‐plane‐jet turbulent mixing analysis via a kinetic theory approach
Authors: Chuang Shu‐Hao , Hong Zuu‐Chang , Wang Jhy‐Horng 
Published: November 2005

AbstractTurbulent mixing of a single jet, twin jets, triple jets and multiple jets is synthetically analysed in this paper. Chung's kinetic theory of turbulence and a modified Green's function are employed to solve this problem. The probability density function of fluid elements in the velocity space of multiple plane jets and the corresponding turbulence correlations are revealed in this analysis. The calculated results are found to be in good agreement with the available experimental data. The internal physical structure of the turbulent mixing mechanism seems better understood via the kinetic theory approach. The present study provides the fundamentals for theoretical understanding of multiple‐jet turbulent mixing and further application to multiple‐jet turbulent combustion analysis.
Finite element solution of the incompressible Navier‐Stokes equations by a Helmholtz velocity decomposition
Authors: Peeters M. F. , Habashi W. G. , Nguyen B. Q. 
Published: November 2005

AbstractFinite element solution methods for the incompressible Navier‐Stokes equations in primitive variables form are presented. To provide the necessary coupling and enhance stability, a dissipation in the form of a pressure Laplacian is introduced into the continuity equation. The recasting of the problem in terms of pressure and an auxiliary velocity demonstrates how the error introduced by the pressure dissipation can be totally eliminated while retaining its stabilizing properties. The method can also be formally interpreted as a Helmholtz decomposition of the velocity vector.The governing equations are discretized by a Galerkin weighted residual method and, because of the modification to the continuity equation, equal interpolations for all the unknowns are permitted. Newton linearization is used and at each iteration the linear algebraic system is solved by a direct solver. Convergence of the algorithm is shown to be very rapid. Results are presented for two‐dimensional flows in various geometries.
Three‐dimensional spectral approximations to Stokes flow between eccentrically rotating cylinders
Authors: Roberts G. W. , Davies A. R. , Phillips T. N. 
Published: November 2005

AbstractA three‐dimensional spectral algorithm for the solution of Stokes flow between eccentrically rotating cylinders is described. Included in the model are pressure boundary conditions at the two ends of the finite length cylinders and the effect of a fluid line source on the inner cylinder. A comparison of results for the load and couple on the inner cylinder is made with those available from lubrication theory in the absence of a line source. Good agreement is shown for long, short and finite journal bearings when the various geometrical assumptions inherent in the lubrication analysis are satisfied.
A finite element scheme based on the velocity correction method for the solution of the time‐dependent incompressible Navier‐Stokes equations
Authors: Kovacs Agnes , Kawahara Mutsuto 
Published: November 2005

AbstractIn this paper a finite element solution for two‐dimensional incompressible viscous flow is considered. The velocity correction method (explicit forward Euler) is applied for time integration. Discretization in space is carried out by the Galerkin weighted residual method. The solution is in terms of primitive variables, which are approximated by piecewise bilinear basis functions defined on isoparametric rectangular elements. The second step of the obtained algorithm is the solution of the Poisson equation derived for pressure. Emphasis is placed on the prescription of the proper boundary conditions for pressure in order to achieve the correct solution. The scheme is completed by the introduction of the balancing tensor viscosity; this makes this method stable (for the advection‐dominated case) and permits us to employ a larger time increment. Two types of example are presented in order to demonstrate the performance of the developed scheme. In the first case all normal velocity components on the boundary are specified (e.g. lid‐driven cavity flow). In the second type of example the normal derivative of velocity is applied over a portion of the boundary (e.g. flow through sudden expansion). The application of the described method to non‐isothermal flows (forced convection) is also included.
A time‐splitting method for the three‐dimensional shallow water equations
Authors: De Goede E. D. 
Published: November 2005

AbstractIn this paper we describe a time‐splitting method for the three‐dimensional shallow water equations. The stability of this method neither depends on the vertical diffusion term nor on the terms describing the propagation of the surface waves. The method consists of two stages and requires the solution of a sequence of linear systems. For the solution of these systems we apply a Jacobi‐type iteration method and a conjugate gradient iteration method. The performance of both methods is accelerated by a technique based on smoothing. The resulting method is mass‐conservative and efficient on vector and parallel computers. The accuracy, stability and computational efficiency of this method are demonstrated for wind‐induced problems in a rectangular basin.
A compressible three‐dimensional design method for radial and mixed flow turbomachinery blades
Authors: Zangeneh M. 
Published: November 2005

AbstractA fully three‐dimensional compressible inverse design method for the design of radial and mixed flow turbomachines is described. In this method the distribution of the circumferentially averaged swirl velocity rVθ on the meridional geometry of the impeller is prescribed and the corresponding blade shape is computed iteratively. Two approaches are presented for solving the compressible flow problem. In the approximate approach the pitchwise variation in density is neglected and as a result the algorithm is simple and efficient. In the exact approach the velocities and density are computed throughout the three‐dimensional flow field by employing a fast fourier transform in the tangential direction. The results of the approximate and exact approach are compared for the case of a high‐speed (subsonic) radial‐inflow turbine and it is shown that the difference between the blade shapes computed by the two methods is well within the manufacturing tolerances. The method was validated by calculating the flow through a designed high‐speed radial‐inflow turbine by using a three‐dimensional inviscid Euler solver. Very good correlation was obtained between the specified and computed rVθ‐distributions.
Variational formulation of three‐dimensional viscous free‐surface flows: Natural imposition of surface tension boundary conditions
Authors: Ho Lee‐Wing , Patera Anthony T. 
Published: November 2005

AbstractWe present a new surface‐intrinsic linear form for the treatment of normal and tangential surface tension boundary conditions in C0‐geometry variational discretizations of viscous incompressible free‐surface flows in three space dimensions. The new approach is illustrated by a finite (spectral) element unsteady Navier‐Stokes analysis of the stability of a falling liquid film.
A practical implementation of turbulence models for the computation of three‐dimensional separated flows
Authors: Marx Yves P. 
Published: November 2005

AbstractAn upwind MUSCL‐type implicit scheme for the three‐dimensional Navier‐Stokes equations is presented and details on the implementation for three‐dimensional flows of a ‘diagonal’ upwind implicit operator are developed. Turbulence models for separated flows are also described with an emphasis on the numerical specificities of the Johnson‐King non‐equilibrium model. Good predictions of separated two‐ and three‐dimensional flows are demonstrated.
A moving grid method applied to one‐dimensional non‐stationary flame propagation
Authors: Mack A. , Weber H. J. , Roth P. 
Published: November 2005

AbstractThe paper presents applications of a moving grid method to the combined problem of ignition and premixed flame propagation in a closed vessel. This method belongs to the general class of adaptive grid techniques for the numerical integration of evolutionary partial differential equations and is based on the method of lines with variable node position. In the present case the motion of the grid and the solution of the partial differential equations are strongly coupled by an implicit formulation. The problem is reduced to an initial value problem for a stiff differential‐algebraic system. The continuously moving grid is determined by the equidistribution of a positive function which depends on the solution of the partial differential equations. A differential‐algebraic system solver is used for the time integration of the initial value problem. The numerical results of the test problems demonstrate the computational efficiency and the capability of the method to resolve the main features of the solution.
Shock capturing for steady, supersonic, two‐dimensional isentropic flow
Authors: Glaister P. 
Published: November 2005

AbstractA finite difference scheme is presented for the solution of the two‐dimensional equations of steady, supersonic, isentropic flow. The scheme incorporates numerical characteristic decomposition, is shock‐capturing by design and incorporates space marching as a result of the assumption that the flow is wholly supersonic in at least one space dimension. Results are shown for problems involving oblique hydraulic jumps and reflection from a wall.
Computer‐aided design of channel expansions and contractions
Authors: Soulis Johannes Vassiliou , Psoni Georgia Apostolou 
Published: November 2005

AbstractA numerical method for designing open channel expansions and contractions to give a specified depth distribution is presented. The design of channels with prescribed depths‐velocities is important because, amongst other things, boundary layer separation can be avoided. Cavitation can also be avoided by prescribing depth‐velocity values that do not exceed certain critical values. The numerical scheme involves iteration between the direct solution (analysis) of a newly developed numerical algorithm and an inverse (design) solution. The governing system of PDEs is transformed into an equivalent system applied over a square grid network. The design procedure, which is based on two levels of design, yields a new set of co‐ordinates for the channel geometry. This new geometry is used in the next iteration of the direct solution. Various channel expansions and contractions have been designed for supercritical flow conditions. Computed results also show how friction affects the channel shape. A numerical experiment has been carried out to establish the design capabilities. The new numerical procedure is a comparatively fast and reliable method for the purpose for which it was set forth. The method can be used either to generate entire new channel shapes or to modify regions of side walls.
Spin‐up in a semicircular cylinder
Authors: Andersson H. I. , Billdal J. T. , Van Heijst G. J. F. 
Published: November 2005

AbstractThis paper addresses the spin‐up from rest of a free‐surface fluid confined in a cylindrical container with a semicircular cross‐section. The flow in the various stages of the spin‐up process has been calculated numerically by using the finite‐volume technique on a three‐dimensional grid. Local grid refinement was applied in order to capture the effects of the boundary layer at the lateral boundaries and of the Ekman layer at the bottom. The numerical results agree very well with laboratory observations.
Prediction of the turbulent boundary layer development by the lag‐entrainment method
Authors: Yavuz Tahir , Özkiliç Serpil 
Published: November 2005

AbstractThe lag‐entrainment method, which is a well‐established integral method for predicting the development of turbulent boundary layers, is used in this study to predict two‐dimensional turbulent separated flow. The method is used in an inverse mode, in which the displacement thickness is specified together with other integral parameters of the boundary layer. It is concluded that the prediction of two‐dimensional separated flow by an integral method is feasible, but there is a need for accurate data for both equilibrium and general separated flows for making a comparison.
Estimating rainfall‐run‐off model parameters by non‐linear minimization
Authors: Yu Yun‐Sheng , Guangte Wang 
Published: November 2005

AbstractExisting discrete, linear rainfall‐run‐off models generally require the effective rainfall of a given storm as the input for computing the run‐off hydrograph. This paper proposes a rainfall‐run‐off model which uses the rainfall hyetograph as input and directly accounts for rainfall losses. The model combines an ARMA model and a modified Philip equation for rainfall losses due to infiltration. For a given watershed with measured rainfall hyetograph and the corresponding run‐off hydrograph, optimal values of model parameters are estimated by using a non‐linear iterative technique. Applications of the model to two different watersheds show that the computed run‐off hydrographs agree well with the measurements. The proposed model is a viable alternative to the widely used unit‐hydrograph method.
Time‐dependent solution of the incompressible Navier‐Stokes equations to simulate air‐conditioning
Authors: Daniels H. , Rouvé G. 
Published: November 2005

AbstractComputer simulations may contribute significantly to the optimal design of air‐conditioning systems. To capture the effects of partially permeable walls such as bookshelves on the movement of air and heat, it is necessary to extend the density‐dependent Navier‐Stokes equations by an additional friction term. The finite element technique is convenient to approximate the extended equations in spatial co‐ordinates. For the time co‐ordinate a recently proposed semi‐implicit finite difference method is very efficient in terms of accuracy and computational complexity. A pressure correction approach is most appropriate to decouple the primitive variables in the extended Navier‐Stokes equations. The resulting algorithm has the interesting feature that small symmetric positive definite systems of equations can be solved sequentially for each of the primitive variables. Iterative solution of the systems of equations with preconditioned conjugate gradients combined with a compressed storage scheme allows fine grid computations at affordable costs. As an example a two‐dimensional version of the code was applied to an enclosure which was heated from the side and contained a porous wall. The time‐dependent computational results are compared with measurement data.
A finite element study of incompressible flows past oscillating cylinders and aerofoils
Authors: Mittal S. , Tezduyar T. E. 
Published: November 2005

AbstractWe present our numerical results for certain unsteady flows past oscillating cylinders and aerofoils. The computations are based on the stabilized space‐time finite element formulation. The implicit equation systems resulting from the space‐time finite element discretizations are solved using iterative solution techniques.One of the problems studied is flow past a cylinder which is forced to oscillate in the horizontal direction. In this case we observe a change from an unsymmetric mode of vortex shedding to a symmetric one. An extensive study was carried out for the case in which a cylinder is mounted on lightly damped springs and allowed to oscillate in the vertical direction. In this case the motion of the cylinder needs to be determined as part of the solution, and under certain conditions this motion changes the vortex‐shedding pattern of the flow field significantly. This non‐linear fluid‐structure interaction exhibits certain interesting behaviour such as ‘lock‐in’ and ‘hysteresis’, which are in good agreement with the laboratory experiments carried out by other researchers in the past. Preliminary results for flow past a pitching aerofoil are also presented.
On a network method for unsteady incompressible fluid flow on triangular grids
Authors: Hall C. A. , Porsching T. A. , Mesina G. L. 
Published: November 2005

AbstractThe dual variable method for Delaunay triangulations is a network‐theoretic method that transforms a set of primitive variable finite difference or finite element equations for incompressible flow into an equivalent system which is one‐fifth the size of the original. Additionally, it eliminates the pressures from the system and produces velocities that are exactly discretely divergence‐free. In this paper new discretizations of the convection term are presented for Delaunay triangulations, the dual variable method is extended to tessellations that contain obstacles, and an efficient algorithm for the solution of the dual variable system is described.