摘要:

To upgrade the efficiency and stability of the successive substitution (SS) and Newton-Raphson (NR) schemes, the concept of input-output-controlled solvers (IOCS) is introduced. By employing the formal properties of the constrained version of the SS and NR schemes, the IOCS algorithm can handle indefiniteness of the system Jacobian, can maintain iterate monotonicity, and provides for separate control of load incrementation and iterate excursions, as well as having other features. To illustrate the algorithmic properties, the results for several benchmark examples are presented. These define the associated numerical efficiency and stability of the IOCS.

ISSN:0149-5720    

DOI:10.1080/10407788808913637

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

An analysis and evaluation are presented for a new method of time integration for fluid dynamic equations proposed by Dietrich. The method, called the filtered leap-frog-trapezoidal ( FLT) scheme, is analyzed for the one-dimensional constant-coefficient advection equation and is shown to have some advantages for quasi-steady flows. A modification( FLTW) using a weighted combination of FLT and leapfrog is developed which retains the advantages for steady flows, increases accuracy for time-dependent flows, and involves little coding effort. Merits and applicability are discussed.

ISSN:0149-5720    

DOI:10.1080/10407788808913638

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The problem of three-dimensional solidification occurs in many practical applications. A numerical grid generation approach is taken to study solidification of three-dimensional objects with arbitrary temperature distributions over one of the bounding surfaces. The formulation of the problem is based on the conduction model, and the interface is characterized by the Stefan condition. Elliptic-type grid generation expressions are used to construct a three-dimensional mesh over the solution domain, which is continuously updated to account for the moving interface. Several examples are presented to demonstrate the applicability of the technique to such moving-boundary problems.

ISSN:0149-5720    

DOI:10.1080/10407788808913639

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

This paper compares the boundary-filled coordinates/finite-difference scheme with a finite-element method for solving transient conduction problems in complex geometries. Various boundary conditions are considered on two-dimensional bodies with square and completely circular cross sections and a circular airfoil cross section. Wherever possible, the temperature distribution obtained numerically using both methods is compared with the analytic solution. For an identical mesh system, the boundary-fitted coordinates approach is found to be more accurate and economical in terms of both computational time and storage requirement than the finite-element method. A parametric study of the conduction problem for various heat generation rates and Biot numbers has been performed.

ISSN:0149-5720    

DOI:10.1080/10407788808913640

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A detailed study of the pressure-weighted interpolation method (PWIM) using a non-staggered grid proposed by Rhie and Chow [7] was conducted. Its implementation in the SIMPLEC algorithm in order to obtain results independent of relaxation factor is described. A comparison of predicted results for two test cases, one a flow in a shear-driven cavity and the other a laminar contraction flow, was made using both staggered and nonstaggered grids. Both hybrid and QUICK differencing schemes were used. QUICK differencing with a nonstaggered grid yielded results in closest agreement with experimental and numerical data. It was also found that in regions of very rapidly varying pressure gradients, PWIM can predict physically unrealistic convective velocities

ISSN:0149-5720    

DOI:10.1080/10407788808913641

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A numerical study of a buoyancy-induced flow generated by a finite-size heat source located on a vertical wall of an enclosure with a single opening is carried out. A two-dimensional laminar flow is assumed. Employing a stream function vorticity formulation within the framework of the Boussinesq approximations, the temperature and the flow fields are computed. The effect of the opening on the induced flow is investigated in terms of the size and the location of the opening. Numerical results are obtained for a wide range of governing parameters, particularly the Rayleigh number. The Prandtl number is taken as that corresponding to air at normal con ditions, Pr = 0.72, and the aspect ratio of the enclosure is varied. Of particular interest were the flow generated in the vicinity of the opening, the flow adjacent to the heated surface, and any stratification that might arise in the enclosure. All these and several other relevant aspects are considered in this study. The numerical formulation for the boundary conditions is a very important consideration and is discussed. Other relevant and important numerical aspects are also considered in this paper.

ISSN:0149-5720    

DOI:10.1080/10407788808913642

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor