bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduction of Shp-2 Expression by Small Interfering RNA Reduces Murine Embryonic Stem Cell-Derived In Vitro Hematopoietic Differentiation
Authors: Zou Gang-Ming , Chan Rebecca J. , Shelley W. Christopher , Yoder Mervin C.
Published: November 2005

Shp-2 is a member of a small family of cytoplasmic Src homology 2 (SH2) domain-containing protein tyrosine phosphatases. Although Shp-2 has been shown to be necessary for hematopoiesis using a mouse model expressing a mutant residual protein (Shp-2Δ/Δ), we used small interfering RNA (siRNA) to reduce Shp-2 expression and examined the consequences on embryonic stem cell (ESC)-derived hemangioblast, primitive, and definitive hematopoietic development. We found that at a concentration of 50 nM, Shp-2 siRNA effectively diminished Shp-2 expression in differentiating embryoid bodies. Hemangioblast, primitive, and definitive hematopoietic progenitor formation was decreased significantly after transfection with Shp-2 siRNA but not with scrambled siRNA. Because Shp-2 is involved in signals emanating from the basic fibroblast growth factor (bFGF) receptor, we asked whether Shp-2 functions in bFGF-mediated hemangioblast development. Reduction of Shp-2 expression using siRNA, but not scrambled siRNA, blocked the bFGF-induced increase in hemangioblast development. Using siRNA as an independent method of reducing Shp-2 function, in contrast to the mutant mouse model (Shp-2Δ/Δ) previously used, we demonstrate that Shp-2 is required in hemangioblast, primitive, and definitive progenitor hematopoietic development and that Shp-2 is integrally necessary for bFGF-mediated hemangioblast production.
Gene-Expression Profiling and the Future of Adjuvant Therapy
Authors: Vijver Marc
Published: November 2005

Learning Objectives

After completing this course, the reader will be able to:Explain how clinical experience influences treatment selection and how this is likely to be refined by molecular diagnosis in the future.Describe the potential of gene profiling in personalized cancer medicine.Discuss some of the limitations of clinical medicine as it relates to the rapid application of gene-expression profiling.

Access and take the CME test online and receive 1 hour of AMA PRA category 1 credit at CME.TheOncologist.com

Gene-expression profiling can help distinguish between patients at high risk and those at low risk for developing distant metastases, and so identify patients for adjuvant therapy. For several years, the Netherlands Cancer Institute has been working on gene-expression profiling of breast cancer using a microarray platform containing 25,000 genes. Using supervised classification, a prognostic classifier consisting of 70 genes could be identified. In addition to providing prognostic information, gene profiling should also enable us to detect patients who are likely to respond to particular adjuvant interventions. Well-known predictors for response to systemic therapy include estrogen receptor status HER-2 status, c-kit mutation, and epidermal growth factor receptor mutation. Because of the long periods required for predicting responsiveness in the adjuvant setting, neoadjuvant trials promise far quicker results. Several neoadjuvant studies are under way or planned to investigate gene-expression profiling as a means of predicting the therapeutic response to doce taxel (Taxotere®; Aventis Pharmaceuticals Inc., Bridgewater, NJ, http://www.aventispharma-us.com), paclitaxel (Taxol®; Bristol-Myers Squibb, Princeton, NJ, http://www.bms.com), cyclophosphamide, and doxorubicin (Adriamycin®; Bedford Laboratories, Bedford, OH, http://www.bedfordlabs.com) in breast cancer patients. It is expected that in the coming years an increasing number of novel prognostic and predictive tests will help in guiding the adjuvant systemic treatment of breast cancer and other malignancies.
Can We Approach Zero Relapse in Breast Cancer?
Authors: Mamounas Eleftherios P.
Published: November 2005

Learning Objectives

After completing this course, the reader will be able to:Discuss the factor most likely to contribute to further decreases in breast cancer mortality.Describe the achievments made in the adjuvant treatment of node-negative and node-positive breast cancer.Explain the evolving role of targeted therapies and genomics in breast cancer.

Access and take the CME test online and receive 1 hour of AMA PRA category 1 credit at CME.TheOncologist.com

Adjuvant hormonal therapy and adjuvant chemotherapy have contributed significantly to the falling rates of breast cancer mortality. The introduction of taxanes and aromatase inhibitors in the adjuvant setting represents recent important improvements. More recently, the demonstration of significant benefit in the adjuvant setting with novel molecular targeted therapies (such as trastuzumab [Herceptin®; Genentech, Inc., South San Francisco, CA, http://www.gene.com]) is already beginning to have a substantial impact on the adjuvant treatment of patients with certain tumor characteristics (i.e., HER-2 positivity). Neoadjuvant treatment represents an approach that offers an intermediate end point (i.e., pathologic complete response) that can be used as a marker of therapeutic activity. Furthermore, the use of genomic profiling is starting to replace the traditional prognostic and predictive factors currently used to estimate risks for recurrence and response to particular adjuvant therapies. These recent developments have demonstrated that the notion of approaching zero relapse in breast cancer patients is now within our reach.
Nickel Compounds
Authors: Lascelles Keith , Morgan Lindsay G. , Nicholls David , Beyersmann Detmar
Published: November 2005

The article contains sections titled:1.Introduction2.Inorganic Nickel Compounds3.Nickel Tetracarbonyl4.Nickel Salts of Organic Acids5.Organonickel Compounds6.Analysis7.Economic Aspects8.Toxicology8.1.Distribution in the Environment8.2.Mammalian Toxicology
Development of New Photocatalytic Water Splitting into H2 and O2 Using Two Different Semiconductor Photocatalysts and a Shuttle Redox Mediator IO3‐/I‐.
Authors: Abe Ryu , Sayama Kazuhiro , Sugihara Hideki
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
New Odorless Protocols for Efficient Pauson—Khand Annulations.
Authors: Brown Jack A. , Irvine Stephanie , Kerr William J. , Pearson Colin M.
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
Palladium‐Catalyzed Cross‐Coupling of Alkynylzincs with Allylic Electrophiles: An Efficient and Selective Synthesis of Stereo‐ and Regio‐Defined 1,4‐Enynes.
Authors: Qian Mingxing , Negishi Ei‐ichi
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
Nickel‐ and Palladium‐Catalyzed Cross‐Coupling Reaction of Polyfluorinated Arenes and Alkenes with Grignard Reagents.
Authors: Saeki Tomoyuki , Takashima Yohei , Tamao Kohei
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
Controlled Monoarylation of Dibromoarenes in Water with a Polymeric Palladium Catalyst.
Authors: Uozumi Yasuhiro , Kikuchi Makoto
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
Importance of Chiral Phase‐Transfer Catalysts with Dual Functions in Obtaining High Enantioselectivity in the Michael Reaction of Malonates and Chalcone Derivatives.
Authors: Ooi Takashi , Ohara Daisuke , Fukumoto Kazuhiro , Maruoka Keiji
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
Synthesis of Fused or Not β‐Lactam‐biaryl Hybrids by Free Radical Aryl—Aryl Coupling of 2‐Azetidinone‐tethered Haloarenes.
Authors: Alcaide Benito , Almendros Pedro , Pardo Carmen , Rodriguez‐Vicente Alberto , Ruiz M. Pilar
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
Regioselective ortho‐Lithiation of 3‐Aryl and 3‐Styryl Furans.
Authors: Tofi Maria , Georgiou Thomas , Montagnon Tamsyn , Vassilikogiannakis Georgios
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
Reaction of 2‐Acyl‐6‐methylbenzo[b]furan‐3‐acetic Acids Derivatives with Hydrazine.
Authors: Tolkunov Valery S. , Perepichka Igor F. , Dulenko Vladimir I.
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
2‐Aminobenzothiazoles from Three‐Component Condensation with Formaldehyde and Amines.
Authors: Pavlenko A. A. , Shikhaliev Kh. S. , Ermolova G. I. , Verezhnikov V. N.
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
Synthesis and Anticancer Activity Studies on Some 2‐Chloro‐1,4‐bis‐ (5‐substituted‐1,3,4‐oxadiazol‐2‐ylmethyleneoxy)phenylene Derivatives.
Authors: Holla B. Shivarama , Poojary K. Narayana , Bhat K. Subrahmanya , Ashok Mithun , Poojary Boja
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
Two‐Step Metal‐Mediated Transformation of Isoxazolidine‐5‐spirocyclopropanes into Pyridone Derivatives.
Authors: Revuelta Julia , Cicchi Stefano , Brandi Alberto
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
Catalytic C—C Coupling Reactions at Nickel by C—F Activation of a Pyrimidine in the Presence of a C—Cl Bond: The Crucial Role of Highly Reactive Fluoro Complexes.
Authors: Steffen Andreas , Sladek Marianna I. , Braun Thomas , Neumann Beate , Stammler Hans‐George
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
Synthesis and Biological Activity of N′‐(Substituted pyrimidin‐2‐yl)‐N‐dichlorochrysanthemoyl Thioureas and Their Fused Heterocyclic Compounds.
Authors: Xue Sijia , Guo Yanling , Li Jingzhi , Ke Shaoyong , Duan Liping
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
New 7‐Phosphanorbornenes Derived from 2‐Methyl‐1‐phenyl‐ and 1‐Cyclohexyl‐3‐methyl‐2,5‐dihydro‐1H‐phosphole 1‐Oxides.
Authors: Kovacs Janos , Balazsdi Szabo Nora , Nagy Zoltan , Ludanyi Krisztina , Keglevich Gyoergy
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
A New Route to Methyl (R,E)‐(‐)‐Tetradeca‐2,4,5‐trienoate (VIII) (Pheromone of Acanthoscelides obtectus) Utilizing a Palladium‐Catalyzed Asymmetric Allene Formation Reaction.
Authors: Ogasawara Masamichi , Nagano Takashi , Hayashi Tamio
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
Crystalline Molecular Machines: Encoding Supramolecular Dynamics into Molecular Structure
Authors: Garcia‐Garibay Miguel A.
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
Generation of Cycloalkynes by Hydro‐Iodonio‐Elimination of Vinyl Iodonium Salts
Authors: Okuyama Tadashi , Fujita Morifumi
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
Protein‐Reactive Natural Products
Authors: Drahl Carmen , Cravatt Benjamin F. , Sorensen Erik J.
Published: November 2005

For Abstract see ChemInform Abstract in Full Text.
Microwave‐Assisted Paal–Knorr Reaction – Three‐Step Regiocontrolled Synthesis of Polysubstituted Furans, Pyrroles and Thiophenes
Authors: Minetto Giacomo , Raveglia Luca F. , Sega Alessandro , Taddei Maurizio
Published: November 2005

An efficient and highly versatile synthesis of furans, pyrroles and thiophenes is described. Starting from commercially available or easily prepared β‐keto esters, functional homologation provides differently substituted 1,4‐diketones that can be transformed, through a microwave‐assisted Paal–Knorr condensation, into the corresponding methoxycarbonyl heterocycles. The methoxycarbonyl moiety can be directly transformed into an NH2 group by hydrolysis to carboxylic acid and Curtius rearrangement or into an amide by reaction with a primary amine in the presence of Me3Al. The method is compatible with the presence of a CbzNH group so that the final heterocycle can be inserted into a peptide sequence as a turn inducer. By using this procedure, a collection of more than 60 different tetrasubstitued pyrroles or trisubstituted thiophenes has been prepared. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
The Ligand‐Exchange Process of P–Hapical Phosphoranes and the Thermal Formation and Pseudorotation of Anti‐Apicophilic Spirophosphoranes
Authors: Kojima Satoshi , Kajiyama Kazumasa , Nakamoto Masaaki , Matsukawa Shiro , Akiba Kin‐ya
Published: November 2005

Monocyclic P–Hapical phosphoranes 10 bearing a ring‐opened Martin ligand are formed upon treatment of the P–Hequatorial spirophosphorane 7 with more than 2 equiv. of alkyllithium compounds. A ligand‐exchange process of these phosphoranes 10 involving the interconversion of the bidentate Martin ligand with the monodentate Martin ligand was found to proceed, probably through a hexacoordinate phosphorus atom. Heating of 10 in nondonating solvents furnished alkylspirophosphoranes 5, whereas heating of 10 in donor solvents led to the formation of anti‐apicophilic phosphoranes 6, a new class of phosphoranes in which the less apicophilic carbon substituent occupies an apical position and the more apicophilic oxygen atom occupies an equatorial position. These phosphoranes 6 were found to completely convert into their energetically more stable Cequatorial,Oapical stereoisomers 5 upon heating. On the basis of kinetic examinations of the cyclization process of 10, the formation of 6 can be rationalized by the enhanced nucleophilicity of the hydroxy group in the donor solvents. The isomer 5b was estimated to be more stable than 6b (R = nBu) by 12 kcal mol–1 from kinetic studies on the pseudorotation of 6b to 5b. This is in good agreement with theoretical calculations with analogous 5a and 6a (R = Me), which estimate the difference in energy to be 14.1 kcal mol–1. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
The calculation of incompressible separated turbulent boundary layers
Authors: Kogan A. , Migemi S.
Published: November 2005

The algebraic turbulent model of Baldwin and Lomax was incorporated into the incompressible full Navier–Stokes code FIDAP. This model was extensively tested in the past in finite difference codes. We believe that the incorporation of the model also into the finite element code has resulted in a practical method to compute a variety of separated turbulent 2D flows. Firstly, we use the model to compute the attached flow about an aerofoil. Next, the application of the model to separated flows is presented by computing the flows at high angles of attack up to maximum lift. It is shown that the model is capable of predicting separation, steady stall and CLmax. As a difficult test of the model we compute the laminar separation bubble development directly using the full Navier–Stokes finite element code. As far as we know, this approach has not yet been reported. The importance of using an appropriate upwinding is discussed. When possible, comparison of computed results with experiments is presented and the agreement is good.
Upwind discretization of the steady Navier–Stokes equations
Authors: Koren Barry
Published: November 2005

A discretization method is presented for the full, steady, compressible Navier–Stokes equations. The method makes use of quadrilateral finite volumes and consists of an upwind discretization of the convective part and a central discretization of the diffusive part. In the present paper the emphasis lies on the discretization of the convective part. The solution method applied solves the steady equations directly by means of a non‐linear relaxation method accelerated by multigrid. The solution method requires the discretization to be continuously differentiable. For two upwind schemes which satisfy this requirement (Osher's and van Leer's scheme), results of a quantitative error analysis are presented. Osher's scheme appears to be increasingly more accurate than van Leer's scheme with increasing Reynolds number. A suitable higher‐order accurate discretization of the convection terms is derived. On the basis of this higher‐order scheme, to preserve monotonicity, a new limiter is constructed. Numerical results are presented for a subsonic flat plate flow and a supersonic flat plate flow with oblique shock wave–boundary layer interaction. The results obtained agree with the predictions made. Useful properties of the discretization method are that it allows an easy check of false diffusion and that it needs no tuning of parameters.
Convergence studies with the Sandia Ocean modeling system
Authors: Dietrich David E. , Roache Patrick J. , Marietta Mel G.
Published: November 2005

Five numerical schemes are compared using convergence studies in the framework of the hydrostatic Sandia Ocean Modeling System (SOMS). Three resolutions are used, 40, 20 and 10 km, with respectively three, seven and 15 layers and time steps of 60, 30 and 15 min, so 15 convergence calculations are performed. The same geophysical prototype problem (exhibiting baroclinic instability in a statically stable environment) is used for all calculations.

All five schemes are second‐order‐accurate in space, but those using four‐point interpolations for the Coriolis and pressure gradient terms are shown to produce much more accurate results, with relatively little extra computation, than schemes using two‐point interpolations.

Convergence is also indicated with decreasing horizontal diffusivities of 107, 106, and 105 cm2s−1. Using 107 cm2s−1 diffusivities causes substantial damping of the dominant instabilities during the 30‐day integrations performed, but using 106 cm2 s−1 results in little damping and yields results very close to those using 105 cm2 s−1.

A barotropic (vertically averaged flow) cyclonic northern basin gyre is explained as a weakly forced circulation. Its equilibrium amplitude is determined by a balance between dissipation effects due to horizontal mixing and diffusion, and weak second‐order driving associated with thermodynamic forcing and vorticity dissipation at the basin bottom. It is thus quite sensitive to model dissipation but can be well described by SOMS owing to SOMS' low numerical dissipation.
A formal finite element approach for open boundaries in transport and diffusion ground‐water problems
Authors: Padilla Francisco , Leclerc Michel , Villeneuve Jean‐Pierre
Published: November 2005

In the application of the finite element method to diffusion and convection‐dispersion equations over a ground‐water domain, the Galerkin technique was used to incorporate Neumann (or second‐type) and Cauchy (or third‐type) boundary conditions. While mass movement through open boundaries is a priori unknown, these boundaries are usually treated as a zero Neumann condition at some far distance from the domain of interest. Nevertheless, cheaper and better solutions can be obtained if these unknown conditions are adequately incorporated in the weak formulation and in the transient solution schemes (open boundary condition). Theoretical and numerical proofs are given of the equivalences between this approach and a ‘well‐posed’ problem in a semi‐infinite domain with a zero Neumann condition at a boundary placed at infinity. Transport and diffusion equations were applied in one dimension to show the numerical performances and limitations of this procedure for some linear and non‐linear problems. No a priori limitations are foreseen in order to find similar solutions in two or three dimensions. Thus the spatial discretization in the proximity of open boundaries could be drastically reduced to the domain of interest.
Diffusion flame analysis of an afterburner as a function of the air‐fuel ratio
Authors: Chuang Shu‐Hao , Jiang Jiunn‐Shean
Published: November 2005

The diffusion flame of an afterburner as a function of the air‐fuel ratio is analysed by employing the SIMPLE‐C algorithm and the turbulence κ‐κ model. In the present analysis, better combustion efficiency of an afterburner with a slightly fuel‐lean mixture is shown. The velocity, fuel mass fraction, temperature and combustion efficiency distributions of reacting flow in an afterburner with two V‐gutter flameholders as a function of the air–fuel ratio are also discussed and compared. The calculated results in the present analysis can be applied to the fundamental study of reacting flow in an afterburner.
Non‐oscillatory shock‐capturing finite element methods for the one‐dimensional compressible Euler equations
Authors: Yang J. Y. , Lien Fue‐Sang , Hsu Chang‐An
Published: November 2005

A class of shock‐capturing Petrov–Galerkin finite element methods that use high‐order non‐oscillatory interpolations is presented for the one‐dimensional compressible Euler equations. Modified eigenvalues which employ total variation diminishing (TVD), total variation bounded (TVB) and essentially non‐oscillatory (ENO) mechanisms are introduced into the weighting functions. A one‐pass Euler explicit transient algorithm with lumped mass matrix is used to integrate the equations. Numerical experiments with Burgers' equation, the Riemann problem and the two‐blast‐wave interaction problem are presented. Results indicate that accurate solutions in smooth regions and sharp and non‐oscillatory solutions at discontinuities are obtainable even for strong shocks.
Solution techniques for the vorticity–streamfunction formulation of two‐dimensional unsteady incompressible flows
Authors: Tezduyar T. E. , Liou J. , Ganjoo D. K. , Behr M.
Published: November 2005

A review of our solution techniques for the vorticity–streamfunction formulation of two‐dimensional incompressible flows is presented. While both the viscous and inviscid cases are considered, the derivation of the proper finite element formulations for multiply connected domains is emphasized. In all formulations associated with the vorticity transport equation, the streamline upwind/Petrov–Galerkin method is used. The adaptive implicit–explicit and grouped element‐by‐element solution strategies are employed to maximize the computational efficiency. The solutions obtained in all test cases compare well with solutions from previously published investigations. The convergence and benchmark studies performed in this paper show that the solution techniques presented are accurate, reliable and efficient.
Finite element solution of flow between eccentric cylinders with viscous dissipation
Authors: De Araujo J. H. C. , Ruas V. , Vargas A. S.
Published: November 2005

A computational study of viscous flow between two eccentrically rotating cylinders is presented in which the effect of viscous dissipation is taken into account. The space discretization is based on piecewise linear finite elements with velocity stabilization, while the method of characteristics is used for time integration. Numerical results illustrate the efficiency of the adopted approach.
Algebraic grid generation for complex geometries
Authors: Shih T. I‐P. , Bailey R. T. , Nguyen H. L. , Roelke R. J.
Published: November 2005

An efficient computer programme called GRID2D/3D has been developed to generate single and composite grid systems within geometrically complex two‐ and three‐dimensional (2D and 3D) spatial domains that can deform with time. GRID2D/3D generates single grid systems by using algebraic grid generation methods based on transfinite interpolation. The distribution of grid points within the spatial domain is controlled by stretching functions and grid lines can intersect boundaries of the spatial domain orthogonally. GRID2D/3D generates composite grid systems by patching together two or more single grid systems. The patching can be discontinuous or continuous. For 2D spatial domains the boundary curves are constructed by using either cubic or tension spline interpolation. For 3D spatial domains the boundary surfaces are constructed by using a new technique, developed in this study, referred to as 3D bidirectional Hermite interpolation.
A study of upstream‐weighted high‐order differencing for approximation to flow convection
Authors: Tsui Yeng‐Yung
Published: November 2005

This paper is concerned with a number of upstream‐weighted second‐ and third‐order difference schemes. Also considered are the conventional upwind and central difference schemes for comparison. It commences with a general difference equation which unifies all the given first‐, second‐ and third‐order schemes. The various schemes are evaluated through the use of the general equation. The unboundedness and accuracy of the solutions by the difference schemes are assessed via various analyses: examination of the coefficients of the difference equation, Taylor series truncation error analysis, study of the upstream connection to numerical diffusion, single‐cell analysis. Finally, the difference schemes are tested on one‐ and two‐dimensional model problems. It is shown that the high‐order schemes suffer less from the problem of numerical diffusion than the first‐order upwind difference scheme. However, unboundedness cannot be avoided in the solutions by these schemes. Among them the linear upwind difference scheme presents the best compromise between numerical diffusion and solution unboundedness.
To the boundary and back—a numerical study
Authors: Karni S.
Published: November 2005

This study identifies the key parameters upon which energy absorption at artificial boundaries depends. A thorough numerical study is presented, of typical reflections from open computational boundaries, for problems governed by hyperbolic systems of equations. The emphasis is on systems, where it is often the combination of all boundary procedures that determine the quality of boundary treatment. We study dissipative numerical models which have so far not been analysed to the same extent as non‐dissipative models and employ a Law‐Wendroff‐type scheme as a prototype. While it is widely accepted that dissipative models tend to give fewer problems than non‐dissipative ones, we show a variety of cases where substantial reflections do occur even in ID and quasi‐ID set‐ups, where theory predicts best results. This can partly be explained by the vanishing of dissipation in the far field. Group velocity analysis, justifiable on the grounds of weak dissipation, predicts a pathological behaviour which is confirmed by numerical experiments. We demonstrate strong focusing of asymptotic errors generated at the artificial boundary. Internal reflections due to slowly expanding grids are shown for non‐linear systems. The need for high‐frequency boundary conditions naturally arises and combined low‐high‐frequency boundary recipes following Higdon, Vichnevetsky and Pariser are adapted to systems and tested. Partial cures are also discussed, mainly in terms of pointing out their theoretically limited potential.
Prediction of flow over helically ribbed surfaces
Authors: Henry F. S. , Collins M. W.
Published: November 2005

Fully developed, steady flow through an annulus with a multistart, helical‐ribbed inner cylinder is numerically predicted and compared with available data. To facilitate comparison, the transverse‐ribbed case is included. It is predicted that substantial differences exist between turbulent flow over helical ribs and that over transverse ribs. The predictions clarify the experimental finding that helical‐ribbed cylinders can be expected to have better pressure drop and heat transfer characteristics than transverse‐ribbed cylinders. For this work the AERE Harwell code FLOW3D Release 2 was used.
Diffusion flame analysis of twin plane jets via a kinetic theory approach
Authors: Chuang Shu‐Hao , Hong Zuu‐Chang
Published: November 2005

Diffusion flame solutions of twin plane jets based on a turbulent kinetic theory due to Chung and a Green function method by Hong are presented. The chemical reaction between fuel and oxidizer is assumed to be one‐step, one‐direction and infinitely fast. The solutions are obtained by direct integration over a constructed probability density function in velocity space. The probability density functions of reactants in transverse velocity space, species mass fraction distributions, turbulent transport of momentum and heat, temperature distributions and flame structure are also considered in this paper. The diffusion flame phenomena of the twin plane jets show that the interaction between the two jets is a dominant factor.
A numerical method for subcritical and supercritical open channel flow calculation
Authors: Soulis Johannes Vassiliou
Published: November 2005

A marching finite volume method is presented for the calculation of two‐dimensional, subcritical and supercritical, steady open channel flow including the usually neglected terms of slope and bottom friction. The channel flow will be assumed to be homogeneous, incompressible, two‐dimensional and viscous with wind and Coriolis forces neglected. A hydrostatic pressure distribution is assumed throughout the flow field. The numerical technique used is a combination of the finite element and finite difference methods. A transformation is introduced through which quadrilaterals in the physical domain are mapped into squares in the computational domain. The governing system of PDEs is thus transformed into an equivalent system applied over a square grid network. Comparisons with other numerical solutions as well as with measurements for various open channel configurations show that the proposed approach is a comparatively accurate, reliable and fast technique.
Boundary linear integral method for compressible potential flows
Authors: Fang Z. , Paraschivoiu I.
Published: November 2005

A boundary linear integral method based on Green function theory has been developed to solve the full potential equation for subsonic and transonic flows. In this integral method, potential values in the flow region are determined by potential values represented by boundary integrals and a volume integral. The boundary potential values are obtained by implementing the boundary integrals along boundary segments where a linear potential relation is assumed. The volume integral is evaluated in a grid generated by finite element discretization. The volume integral is evaluated only outside the body. Therefore there is no extra boundary treatment required for evaluation of the volume integral. The source term is assumed to be constant in an element integral volume. The volume integral needs to be evaluated only once and can be stored in computer memory for further usage.
Prediction of wake in a curved duct
Authors: Narasimhan J. L. , Ramjee V. , Diwakar Philip M. , Tulapurkara E. G.
Published: November 2005

Experimental data on the development of an aerofoil wake in a curved stream are compared with calculations based on the k‐ε model of turbulence with standard constants and with the model constant Cμ dependent on the local curvature. The mean velocity profile is asymmetric, the half‐width of the wake is more on the inner side of the curved duct than on the outer side, and the turbulent shear stress decreases rapidly on the outer side. The standard k‐ε model is able to satisfactorily reproduce this behaviour. Making Cμ dependent on the local radius improves the agreement on the inner side but slightly worsens it on the outer side.
A finite element formulation for laminar flow of a fluid with microstructure
Authors: Hogan H. A. , Henriksen M.
Published: November 2005

A finite element formulation for the steady laminar flow of an incompressible fluid with microstructure has been developed. The particular fluids considered are commonly known as micropolar fluids, in which case suspended particulate microstructures are modelled by an ‘extended’ continuum formulation. The particle microspin is a new kinematic variable which is independent of the classical vorticity vector and thereby allows relative rotation between particles and the surrounding fluid. This formulation also gives rise to couple stresses in addition to classical force or traction stresses. The finite element formulation utilizes a variational approach and imposes conservation of mass through a penalty function. A general boundary condition for microspin has been incorporated whereby microspin at a solid boundary is constrained to be proportional to the fluid vorticity. The proportionality constant in this case can vary from zero to unity. Sample solutions are presented for fully developed flow through a straight tube and compared with an analytical solution. Results are also generated for flow through a constricted tube and compared with a Newtonian fluid solution.
Strategies for parallelizing a Navier‐Stokes code on the intel touchstone machines
Authors: Häuser Jochem , Williams Roy
Published: November 2005

The purpose of this paper is to predict the efficiency of the Navier‐Stokes code NSS* which will run on an MIMD architecture parallel machine. Computations are performed using a three‐dimensional overlapping structured multiblock grid. Each processor works with some of these blocks and exchanges data across the boundaries of the blocks. The efficiency of such a code depends on the number of grid points per processor, the amount of computation per grid point and the amount of communication per boundary point. In this paper we estimate these quantities for NSS* and present measurements of communication times for two parallel machines, the Intel Touchstone Delta machine and an Intel iPSC/860 machine, consisting of 520 and 64 Intel i860 processors respectively. The peak performance of the Delta machine is 32 Gflop. Secondly it is shown how, starting from a seven‐block grid of about 5000 000 points for the Hermes space plane, a mesh of 512 equally sized blocks is constructed retaining the original topology. This example demonstrates that multiblock grids provide sufficient control over both the number and size of blocks. Therefore it will be possible to simulate realistic configurations on massively parallel systems with a specified number of processors while achieving good quality load balancing.
Euler solutions for self‐generated rotor blade‐vortex interactions
Authors: Hassan A. A. , Tung C. , Sankar L. N.
Published: November 2005

A finite‐difference procedure has been developed for the prediction of three‐dimensional rotor blade‐vortex interactions. The interaction velocity field was obtained through a non‐linear superposition of the rotor flow field, computed using the unsteady three‐dimensional Euler equations, and the embedded vortex wake flow field, computed using the law of Biot‐Savart. In the Euler model, near wake rotational effects were simulated using the surface velocity ‘transpiration’ approach. As a result, a modified surface boundary condition was prescribed and enforced at each time step of the computations to satisfy the tangency boundary condition. For supercritical interactions using an upstream‐generated vortex, accuracy of the numerical results were found to rely on the user‐specified vortex core radius and vortex strength. For the more general self‐generated subcritical interactions, vortex wake trajectories were computed using the lifting‐line helicopter/rotor trim code CAMRAD. For these interactions, accuracy of the results were found to rely heavily on the CAMRAD‐predicted vortex strength, vortex orientation with respect to the blade, and to a large extent on the user‐specified vortex core radius. Results for the one‐seventh scale model OLS rotor and for a non‐lifting rectangular blade having a NACA0012 section are presented. Comparisons with the experimental windtunnel data are also made.
A split operator scheme for ocean wave simulation
Authors: Li Chi Wai
Published: November 2005

A coupled discrete spectral model was developed for the prediction of ocean waves by solving the energy conservation equation of the two‐dimensional wave spectrum. The model includes the dispersion correction terms in the governing equation to account for the dispersive effect due to the frequency‐dependent velocities of waves. A split operator scheme is used to deal with the numerical problems arising from different terms of the governing equation. The advection terms are solved by the proven accurate minimax characteristics method to avoid excessive numerical damping or oscillations. The dispersion correction terms are solved by central differencing. The source and sink terms are solved by a quasi‐second‐order explicit scheme with limitation on energy growth per time step to allow the use of a large time step. The model was verified by ideal test cases and wave‐hindcasting studies under typhoon conditions in the South China Sea near Hong Kong.
Numerical solution of the viscous stability equations for low‐speed reacting flows
Authors: Mahalingam Shankar
Published: November 2005

The governing equations required to analyse the linear (viscous) stability of low‐speed reacting flows are derived and a solution method based on initial value problems is described. The algorithm accurately reproduces the neutral stability curve for a non‐reacting viscous shear layer, thus providing partial validation. The results for premixed and non‐premixed flames in planar shear layers are presented and discussed.
A PC‐based system for modelling of convection in enclosures on the basis of the Navier‐Stokes equations
Authors: Ermakov M. K. , Gryaznov V. L. , Nikitin S. A. , Pavlovsky D. S. , Polezhaev V. I.
Published: November 2005

A PC‐based system for modelling of convection in enclosures on the basis of the Navier‐Stokes equations is described and a number of test results are given. New examples of mixed convection in a square chamber and thermal convection in ordinary and porous (isotropic and anisotropic) vertical layers are presented which may be of interest in civil and building engineering.
Grid generation for 2D flow problems
Authors: Taniguchi Takeo , Holz Klaus‐Peter , Ohta Chikashi
Published: November 2005

A grid generation method is proposed for an arbitrary two‐dimensional domain. The method, based on the Delaunay triangulation, is modified so that it can be used as a grid generator for an arbitrary two‐dimensional area with complex boundary geometry. Input data for the method are the co‐ordinates of all nodes and the ordering of nodes on each boundary. Its efficiency is examined through a number of actual problems, and a numerical experiment clarifies that the grid generation requires a CPU time which is proportional to the number of nodes.
Computation of incompressible viscous flows by the third‐order upwind finite element method
Authors: Kondo Norio , Tosaka Nobuyoshi , Nishimura Toshio
Published: November 2005

A third‐order upwind finite element scheme is presented for numerical solutions of incompressible viscous flow problems. In order to achieve the third‐order upwind approximation for only the convection term in the Navier‐Stokes equations, a simplified Petrov‐Galerkin formulation in which a modified weighting function is expressed by the sum of a standard weighting function and its second and third spatial derivatives is employed. The mixed method is also employed in the formulation so that a discretization with high‐order accuracy in space is carried out by the use of linear elements. Because a truncation error caused by the third‐order upwind approximation is smaller than that of a first‐order upwind scheme, it is expected that the third‐order upwind scheme will greatly improve the numerical solutions of the Navier‐Stokes equations. Numerical results in one and two dimensions are presented to illustrate the effectiveness of the proposed scheme.
A flux‐based modified method of characteristics
Authors: Roache Patrick J.
Published: November 2005

A flux‐based modified method of characteristics (MMOC) methodology in 1D is described which has the following properties: unconditional stability (though explicit), exact answers for integer CFL (Courant) numbers, completely conservative (locally and globally) and able to utilize various flux limiters and various characteristic‐ (trajectory‐) tracking algorithms. The use of characteristics based on cell‐wise constant characteristic velocities results in considerable code simplification, and Van Leer's MUSCL is an accurate and cost‐effective flux limiter. For CFL≥1 the flux limiter is applied only to the non‐integer part of CFL, whereas the integer part is exact for constant velocities; therefore accuracy improves with larger CFL. It is not a cheap algorithm, although explicit, because the operation count per time step increases with the integer part of CFL, but it is much more accurate than the commonly used implicit upstream differencing. This flux‐based MMOC method is well suited for groundwater flow calculations in which large local Courant numbers arise owing to grid clustering.
Calculation of turbulent combustion of propane in furnaces
Authors: Bai X. S. , Fuchs L.
Published: November 2005

An evaluation of some numerical methods for turbulent reacting flows in furnace‐like geometries is carried out. The Reynolds averaged Navier–Stokes equations and the two‐equation k–ϵ model together with either finite‐rate or infinite‐rate reaction models are solved numerically. Either single‐ or multiple‐step reactions together with the ‘eddy dissipation concept’ (EDC) are used to model reacting flows with finite reaction rates. The numerical scheme is finite difference based, together with a multi‐grid method and a local grid refinement technique. These methods have been used to calculate the combustion of propane in a single‐ and multiple‐burner configurations. In the former case, the sensitivity of the solution to variations in some model parameters (determining the reaction rate) and numerical parameters (mesh spacing) has been studied. It is noted that different dependent variables exhibit different levels of sensitivity to the variation in model parameters. Thus, calibration and validation of models for reacting flows require that one compares the most sensitive variables. For engineering purposes, on the other hand, one may calibrate and validate models with respect to the most relevant variables. Our conclusion is that since sensitivity of the temperature distribution is relatively mild, one can still use EDC‐like methods in engineering applications where details of the temperature field are of minor importance.
Benchmark solutions for the incompressible Navier–Stokes equations in general co‐ordinates on staggered grids
Authors: Oosterlee C. W. , Wesseling P. , Segal A. , Brakkee E.
Published: November 2005

Benchmark problems are solved with the steady incompressible Navier–Stokes equations discretized with a finite volume method in general curvilinear co‐ordinates on a staggered grid. The problems solved are skewed driven cavity problems, recently proposed as non‐orthogonal grid benchmark problems. The system of discretized equations is solved efficiently with a non‐linear multigrid algorithm, in which a robust line smoother is implemented. Furthermore, another benchmark problem is introduced and solved in which a 90° change in grid line direction occurs.
Numerical simulation of a low‐Reynolds‐number turbulent wake behind a flat plate
Authors: Voke Peter R. , Potamitis Socrates G.
Published: November 2005

A numerical simulation of a plane turbulent wake at a very low Reynolds number has been performed using finite volume methods. The wake was produced by allowing two turbulent boundary layers, simulated separately in advance, to interact downstream of the trailing edge of a thin flat plate. A number of innovative numerical techniques were required in the simulation, such as the provision of fully turbulent time‐dependent inflow data from a separate simulation, advective outflow boundary conditions and the approximate representation of an internal solid surface by a method which is computationally efficient. The resulting simulation successfully reproduced many of the statistical properties of the turbulent near‐wake flow at low Reynolds number.
Entrance flow in eccentric annular ducts
Authors: Velusamy K. , Garg Vijay K.
Published: November 2005

A control‐volume‐based solution of the complete set of Navier‐Stokes equations for the laminar, three‐dimensional developing flow in straight, eccentric, cylindrical annular ducts is described. Numerical results for velocity and pressure development, pressure defect and entrance lengths are presented for a wide range of duct parameters, i.e. relative eccentricity ϵ and radius ratio γ. The present results match very well with earlier numerical solutions for the limiting cases of developing flow in concentric ducts and fully developed flow in eccentric ducts. Comparison with earlier approximate results for developing flow in eccentric ducts indicates that the approximate model predicts the velocity and pressure development with an error of about 10%. However, the development length predicted by the approximate model is grossly in error. The pressure defect and development length in eccentric ducts are very high compared with their counterparts in concentric ducts. The pressure defect, development length and maximum velocity increase with the radius ratio for eccentric ducts, while the reverse is true for concentric ducts. Also, the apparent friction factor decreases as the eccentricity increases.
A little more on stabilized Q1Q1 for transient viscous incompressible flow
Authors: Gresho P. M. , Chan S. T. , Christon M. A. , Hindmarsh A. C.
Published: November 2005

In an attempt to overcome some of the well‐known ‘problems’ with the Q1P0 element, we have devised two ‘stabilized’ versions of the Q1Q1 element, one based on a semi‐implicit approximate projection method and the other based on a simple forward Euler technique. While neither one conserves mass in the most desirable manner, both generate a velocity field that is usually ‘close enough’ to divergence‐free. After attempting to analyse the two algorithms, each of which includes some ad hoc ‘enhancements’, we present some numerical results to show that they both seem to work well enough. Finally, we point out that any projection method that uses a ‘pressure correction’ approach is inherently limited to time‐accurate simulations and, even if treated fully implicitly, is inappropriate for seeking steady states via large time steps.
Parallel finite element simulation of 3D incompressible flows: Fluid‐structure interactions
Authors: Mittal S. , Tezduyar T. E.
Published: November 2005

Massively parallel finite element computations of 3D, unsteady incompressible flows, including those involving fluid‐structure interactions, are presented. The computation with time‐varying spatial domains are based on the deforming spatial domain/stabilized space‐time (DSD/SST) finite element formulation. The capability to solve 3D problems involving fluid‐structure interactions is demonstrated by investigating the dynamics of a flexible cantilevered pipe conveying fluid. Computations of flow past a stationary rectangular wing at Reynolds number 1000, 2500 and 107 reveal interesting flow patterns. In these computations, at each time step approximately 3 × 106 non‐linear equations are solved to update the flow field. Also, preliminary results are presented for flow past a wing in flapping motion. In this case a specially designed mesh moving scheme is employed to eliminate the need for remeshing. All these computations are carried out on the Army High Performance Computing Research Center supercomputers CM‐200 and CM‐5, with major speed‐ups compared with traditional supercomputers. The coupled equation systems arising from the finite element discretizations of these large‐scale problems are solved iteratively with diagonal preconditioners. In some cases, to reduce the memory requirements even further, these iterations are carried out with a matrix‐free strategy. The finite element formulations and their parallel implementations assume unstructured meshes.