摘要:

AbstractA time‐marching finite volume numerical procedure is presented for three‐dimensional Euler analysis of turbomachinery flows. The proposed scheme is applied to the conservative form of the Euler equations written in general curvilinear co‐ordinates. A simple but computationally efficient grid is constructed. Numerical solution results for three 3D turbine cascade flows have been presented and compared with available measurements as well as with another state‐of‐the‐art 3D Euler analysis numerical solution in order to demonstrate the accuracy and computational efficiency of the analysis method. Also, the predicted results are compared with a 3D potential flow solver and comparison is made with the analytical solution. The proposed method is an accurate and reliable technique for solving the compressible flow equations in turbomachinery

ISSN:0271-2091    

DOI:10.1002/fld.1650200102

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractIn the first part of this paper a numerical strategy is developed for the numerical simulation of the coextrusion process. Coextrusion consists of extruding many polymers in the same die in order to combine their respective properties. The die is generally flat and quite large and consequently a two‐dimensional approximation is sufficient. The main difficulty is to accurately predict the interfaces between the different layers of polymers. A finite element method based on a pseudoconcentration function is developed to calculate these fluid interfaces. Numerical results are presented for the coextrusion of up to five fluids.In the second part of the paper the above strategy is slightly modified to simulate the film‐casting process. In this case a polymer is stretched (with a draw velocityUL) at the exit of the die in order to produce a very thin layer of polymer that is cooled in contact with a chill roll. Only one polymer‐air interface has to be computed. The draw ratio is defined asDr=UL/U, whereUis the mean velocity of the polymer at the exit of the die. As the draw ratio is increased, instabilities appear and numerical results put in evidence the draw resonance pheno

ISSN:0271-2091    

DOI:10.1002/fld.1650200103

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe solution of the incompressible Navier‐Stokes equations in general two‐ and three‐dimensional domains using a multigrid method is considered. Because a great variety of boundary‐fitted grids may occur, robustness is at a premium. Therefore a new ILU smoother called CILU (collective ILU) is described, based on r‐transformations. In CILU the matrix that is factorized is block‐structured, with blocks corresponding to the set of physical variables. A multigrid algorithm using CILU as smoother is investigated. The performance of the algorithm in two and three dimensions is assessed by numerical experments. The results show that CILU is a good smoother for the incompressible Navier‐Stokes equations discretized on general non‐orthogonal cu

ISSN:0271-2091    

DOI:10.1002/fld.1650200104

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractA new approach has been developed to calculate two‐dimensional steady transonic flows past aerofoils using the Euler equations in streamfunction co‐ordinates. Most existing transonic computation codes require the use of a grid generator to determine a suitable distribution of grid points. Although simple in concept, the grid generation may take a considerable proportion of the CPU time and storage requirements. However, this grid generation step can be avoided by introducing the von Mises transformation, which produces a formulation in streamwise and natural body‐fitting co‐ordinates. In this work a set of Euler equivalent equations in streamfunction co‐ordinates is formulated, consisting of three equations with three unknowns; one is a geometric variable, the streamline ordinatey, and the other two are physical quantities, the density ρ and the vorticity ω. To solve these equations, typedependent differencing, development of a shock point operator, marching from a non‐characteristic boundary and successive line overrelaxation are applied. Particular attention has been paid to the supercritical case where a careful treatment of the shock is essential. It is shown that the shock point operator is crucial to accurately capture shock waves. The computed results show excellent agreement with existing experimental data and other

ISSN:0271-2091    

DOI:10.1002/fld.1650200105

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650200106

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650200107

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650200101

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY