摘要:

AbstractThe commonly accepted linear stability analysis for the forward‐time centred‐space (FTCS) algorithm applied to the transport equation has led to the concept of a cell Reynolds number restriction on the spatial grid size. This paper shows where the commonly accepted original analysis is in error and presents the correct stability restrictions, which are restrictions on the time step, not the spatial grid size. There is no cell Reynolds number restriction. The results are confirmed by numerical computations for the two‐dimensional driven cavity pr

ISSN:0271-2091    

DOI:10.1002/fld.1650050402

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractA numerical and an experimental study of the flow of an incompressible fluid in a polar cavity is presented. The experiments included flow visualization, in two perpendicular planes, and quantitative measurements of the velocity field by a laser Doppler anemometer. Measurements were done for two ranges of Reynolds numbers; about 60 and about 350. The stream function‐vorticity form of the governing equations was approximated by upwind or central finite‐differences. Both types of finite‐difference approximations were solved by a multi‐grid method. Numerical solutions were computed on a sequence of grids and the relative accuracy of the solutions was studied. Our most accurate numerical solutions had an estimated error of 0.1 per cent and 1 per cent forRe= 60 andRe= 350, respectively. It was also noted that the solution to the second order finite difference equations was more accurate, compared to the solution to the first order equations, only if fine enough meshes were used. The possibility of using extrapolations to improve accuracy was also considered. Extrapolated solutions were found to be valid only if solutions computed on fine enough meshes were used. The numerical and the experimental results were found to be in very good ag

ISSN:0271-2091    

DOI:10.1002/fld.1650050403

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractIn this paper the development of a compatible mixed design and analysis method is presented for the quasi‐three‐dimensional finite element blade‐to‐blade program FINSUP. The method consists of two parts. The first is concerned with a method of modelling changes to a blade shape using a surface transpiration model. The second is concerned with determining the relationship between the displaced blade surface and the surface velocity distribution. It is shown that with the Newton‐Raphson procedure adopted in the method a very efficient manner of introducing the design option is possible. As a consequence the resulting program is fast and completely interactive. A number of examples are given to illustrate how the mixed design and analysis mode can be used in practical bla

ISSN:0271-2091    

DOI:10.1002/fld.1650050404

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractA new model is presented for the calculation of the incompressible, inviscid flow around an arbitrary aerofoil undergoing unsteady motion. The technique was developed from the steady flow algorithm of Leishman and Galbraith1in which use was made of a linear distribution of panel vorticity. The procedure is in the same class as that of Basu and Hancock2but, because of the particular approach to the manner of specifying the shed vorticity, only a set of linear simultaneous equations needs be solved, unlike the method of Reference 2, complicated by the necessary solution of a quadratic.A brief history of unsteady flow modelling is given in the introduction, followed by the mathematical details of the current method. Results are presented and discussed for a number of cases which clearly illustrate relevant characteristics of unsteady flow.

ISSN:0271-2091    

DOI:10.1002/fld.1650050405

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractA general implicit (GI) method for solving iteratively the algebraic system arising from a finite difference approximation of an elliptic partial differential equation is formulated. Under certain assumptions this method can be reduced to the already known implicit techniques. It is shown that the GI method has a very special physical meaning when solving fluid flow problems. It is shown also how this method can be optimized to achieve the maximum rate of convergence. Finally it is shown how this new strategy is applied by solving some classical numerical fluid dynamics problems.

ISSN:0271-2091    

DOI:10.1002/fld.1650050406

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractA new method for solving elliptic difference equations is derived based on the strongly implicit method. This parametrized strongly implicit method has three free parameters which may be functions of the field's nodal point. The method has some resemblance to the SOR techniques, but in the present method the off‐diagonal entries are also over‐relaxed. The main application of this method is for transport equations such as those governing the fluid flow and heat transfer fie

ISSN:0271-2091    

DOI:10.1002/fld.1650050407

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractA simple explanation is given of the occurrence of wiggles in the flow field near outflow boundaries. If the shallow‐water equations are solved numerically spurious solutions with an oscillatory character turn out to exist, which can be generated by certain additional numerical boundary conditions on the downstream side. The wiggles usually damp quickly with the distance from the boundary. Some ways of handling the downstream boundary are given which largely avoid the occurrence of wiggle

ISSN:0271-2091    

DOI:10.1002/fld.1650050408

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650050409

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650050410

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650050401

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY