摘要:

AbstractThe paper describes a new approach to approximating the convection term found in typical steady‐state transport equations. A polynomial‐based discretization scheme is constructed around a technique called ‘curvature compensation’; the resultant curvature‐compensated convective transport approximation is essentially third‐order accurate in regions of the solution domain where the concept of order is meaningful. In addition, in linear scalar transport problems it preserves the boundedness of solutions. Sharp changes in gradient in the dependent variable are handled particularly well. But above all, the scheme, when used in conjunction with an ADI pentadiagonal solver, is easy to implement with relatively low computational cost, representing an effective algorithm for the simulation of multi‐dimensional fluid flows. Two linear test problems, for the case of transport by pure convection, are employed in order to assess the merit

ISSN:0271-2091    

DOI:10.1002/fld.1650080602

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe moving boundary (i.e. the piston) within a reciprocating engine poses the problem that as it moves towards the cylinder head it compresses the computational grid lines. Control cells that started with reasonable aspect ratios become so compressed that aspect ratios of 1000 are not unusual in some cases. This, of course, adversely affects numerical accuracy and convergence. It is the purpose of this paper to present a conservative scheme that allows for the removal and addition of grid cells, during simulation, so as to restore reasonable aspect ratios. Results of the computations are presented and compared with experimental data. It is concluded that with the proposed scheme convergence is obtained within fewer iterations, CPU time is reduced and the results are generally in better agreement with experimental data.

ISSN:0271-2091    

DOI:10.1002/fld.1650080603

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper studies the effects of a circular magnetic field on the flow of a conducting fluid about a porous rotating disk. Using modern quasi‐Newton and globally convergent homotopy methods, numerical solutions are obtained for a wide range of magnetic field strengths, suction and injection velocities and Alfven and disk speeds. Results are presented graphically in terms of three non‐dimensional parameters. There is excellent agreement with previous work and asymptotic formu

ISSN:0271-2091    

DOI:10.1002/fld.1650080604

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe behaviour of the pressure correction method is studied for the solution of the incompressible steady‐state Navier‐Stokes and continuity equations in a rotating cylindrical‐polar co‐ordinate system, the specific problem being that of laminar source‐sink flow between two corotating discs. Modifications to improve the linearization and the handling of the rotation terms are introduced, and we compare three extended pressure correction schemes and also the use of a multigrid algorithm in part of the calculation procedure as a line

ISSN:0271-2091    

DOI:10.1002/fld.1650080605

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractA finite element method has been applied to predict the overall features of the fully developed turbulent flow in the non‐circular channels of a rod bundle. The finite element discretization is based on the conventional Galerkin method using an isoparametric quadrilateral element with mixed interpolation.The primary axial flow and turbulent kinetic energy distributions have been predicted for fully developed turbulent flow conditions right up to the wall. The secondary velocity is represented by the stream function‐vorticity formulation and the no‐slip boundary conditions are explicitly introduced in the nonlinear equations by a boundary vorticity formula. The Newton‐Raphson method is applied to the stream function‐vorticity equations and solved simultaneously by the frontal solution technique.A one‐equation eddy viscosity model of turbulence and an algebraic stress transport model have been used to predict primary axial velocity, secondary velocities and turbulent kinetic energy. The predictions obtained for a central subchannel of an equilateral‐triangular rod array with p/d= 1.3 are in reasonable agreement with expe

ISSN:0271-2091    

DOI:10.1002/fld.1650080606

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractIn Sezgin1,2the problems considered are the magnetohydrodynamic (MHD) flows in an electrodynamically conducting infinite channel and in a rectangular duct respectively, in the presence of an applied magnetic field. In the present paper we extend the solution procedure of these papers to two rectangular channels connected by a barrier which is partially conductor and partially insulator. The problem has been reduced to the solution of a pair of dual series equations and then to the solution of a Fredholm's integral equation of the second kind. The infinite series obtained were transformed to finite integrals containing Bessel Junctions of the second kind to avoid the computations of slowly converging infinite series and infinite integrals with oscillating integrands. The results obtained compared well with those of Butsenieks and Shcherbinin3 which were obtained for the perfectly conducting barrier separating the flows.

ISSN:0271-2091    

DOI:10.1002/fld.1650080607

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe problem of mixed convection about non‐isothermal vertical surfaces in a saturated porous medium is analysed using boundary layer approximations. The analysis is made assuming that the surface temperature varies as an arbitrary function of the distance from the origin. A perturbation technique has been applied to obtain the solutions. Using the differentials of the wall temperature, which are functions of distance along the surface, as perturbation elements, universal functions are derived for various values of the governing parameterGr/Re.Both aiding and opposing flows are considered. The universal functions obtained can be used to estimate the heat transfer and fluid velocity inside the boundary layer for any type of wall temperature variation. As a demonstration of the method, heat transfer results have been presented for the case of the wall temperature varying as a power function of the distance from the origin. The results have been studied for various combinations of the parametersGr/Reand the power indexm, taking both aiding and opposing flows into consideration. On comparing these results with those obtained by a similarity analysis, the agreement is found to be goo

ISSN:0271-2091    

DOI:10.1002/fld.1650080608

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650080609

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650080610

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650080611

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY