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Comparison of iterative methods for the solution of compressible-fluid reynolds equation / Nenzi Wang in Transactions of the ASME . Journal of tribology, Vol. 133 N° 2 (Avril 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of tribology > Vol. 133 N° 2 (Avril 2011) . - 07 p. Titre : Comparison of iterative methods for the solution of compressible-fluid reynolds equation Type de document : texte imprimé Auteurs : Nenzi Wang, Auteur ; Shih-Hung Chang, Auteur ; Hua-Chih Huang, Auteur Année de publication : 2012 Article en page(s) : 07 p. Note générale : Tribology Langues : Anglais (eng) Mots-clés : Compressible  flow  Computational  fluid  dynamics  Conjugate  gradient  methods  Differential  equations  Newton  method Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This study presents an efficacy comparison of iterative solution methods for solving the compressible-fluid Reynolds equation in modeling air- or gas-lubricated bearings. A direct fixed-point iterative (DFI) method and Newton's method are employed to transform the Reynolds equation in a form that can be solved iteratively. The iterative solution methods examined are the Gauss–Seidel method, the successive over-relaxation (SOR) method, the preconditioned conjugate gradient (PCG) method, and the multigrid method. The overall solution time is affected by both the transformation method and the iterative method applied. In this study, Newton's method shows its effectiveness over the straightforward DFI method when the same iterative method is used. It is demonstrated that the use of an optimal relaxation factor is of vital importance for the efficiency of the SOR method. The multigrid method is an order faster than the PCG and optimal SOR methods. Also, the multigrid and PCG methods involve an extended coding work and are less flexible in dealing with gridwork and boundary conditions. Consequently, a compromise has to be made in terms of ease of use as well as programming effort for the solution of the compressible-fluid Reynolds equation. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE900013 [...] [article] Comparison of iterative methods for the solution of compressible-fluid reynolds equation [texte imprimé] / Nenzi Wang, Auteur ; Shih-Hung Chang, Auteur ; Hua-Chih Huang, Auteur . - 2012 . - 07 p. Tribology Langues : Anglais (eng) in Transactions of the ASME . Journal of tribology > Vol. 133 N° 2 (Avril 2011) . - 07 p. Mots-clés : Compressible  flow  Computational  fluid  dynamics  Conjugate  gradient  methods  Differential  equations  Newton  method Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This study presents an efficacy comparison of iterative solution methods for solving the compressible-fluid Reynolds equation in modeling air- or gas-lubricated bearings. A direct fixed-point iterative (DFI) method and Newton's method are employed to transform the Reynolds equation in a form that can be solved iteratively. The iterative solution methods examined are the Gauss–Seidel method, the successive over-relaxation (SOR) method, the preconditioned conjugate gradient (PCG) method, and the multigrid method. The overall solution time is affected by both the transformation method and the iterative method applied. In this study, Newton's method shows its effectiveness over the straightforward DFI method when the same iterative method is used. It is demonstrated that the use of an optimal relaxation factor is of vital importance for the efficiency of the SOR method. The multigrid method is an order faster than the PCG and optimal SOR methods. Also, the multigrid and PCG methods involve an extended coding work and are less flexible in dealing with gridwork and boundary conditions. Consequently, a compromise has to be made in terms of ease of use as well as programming effort for the solution of the compressible-fluid Reynolds equation. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE900013 [...]

Fast convergence of iterative computation for incompressible-fluid Reynolds equation / Nenzi Wang in Transactions of the ASME . Journal of tribology, Vol. 134 N° 2 (Avril 2012) 

Public ISBD [article]  in Transactions of the ASME . Journal of tribology > Vol. 134 N° 2 (Avril 2012) . - 04 p. Titre : Fast convergence of iterative computation for incompressible-fluid Reynolds equation Type de document : texte imprimé Auteurs : Nenzi Wang, Auteur ; Kuo-Chiang Cha, Auteur ; Hua-Chih Huang, Auteur Année de publication : 2012 Article en page(s) : 04 p. Note générale : tribology Langues : Anglais (eng) Mots-clés : Reynolds  equation;  iterative  method;  grid  convergence Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : When a discretized Reynolds equation is to be solved iteratively at least three subjects have to be determined first. These are the iterative solution method, the size of gridwork for the numerical model, and the stopping criterion for the iterative computing. The truncation error analysis of the Reynolds equation is used to provide the stopping criterion, as well as to estimate an adequate grid size based on a required relative precision or grid convergence index. In the simulated lubrication analyses, the convergent rate of the solution is further improved by combining a simple multilevel computing, the modified Chebyshev acceleration, and multithreaded computing. The best case is obtained by using the parallel three-level red-black successive-over-relaxation (SOR) with Chebyshev acceleration. The speedups of the best case relative to the case using sequential SOR with optimal relaxation factor are around 210 and 135, respectively, for the slider and journal bearing simulations. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE9000134000002 [...] [article] Fast convergence of iterative computation for incompressible-fluid Reynolds equation [texte imprimé] / Nenzi Wang, Auteur ; Kuo-Chiang Cha, Auteur ; Hua-Chih Huang, Auteur . - 2012 . - 04 p. tribology Langues : Anglais (eng) in Transactions of the ASME . Journal of tribology > Vol. 134 N° 2 (Avril 2012) . - 04 p. Mots-clés : Reynolds  equation;  iterative  method;  grid  convergence Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : When a discretized Reynolds equation is to be solved iteratively at least three subjects have to be determined first. These are the iterative solution method, the size of gridwork for the numerical model, and the stopping criterion for the iterative computing. The truncation error analysis of the Reynolds equation is used to provide the stopping criterion, as well as to estimate an adequate grid size based on a required relative precision or grid convergence index. In the simulated lubrication analyses, the convergent rate of the solution is further improved by combining a simple multilevel computing, the modified Chebyshev acceleration, and multithreaded computing. The best case is obtained by using the parallel three-level red-black successive-over-relaxation (SOR) with Chebyshev acceleration. The speedups of the best case relative to the case using sequential SOR with optimal relaxation factor are around 210 and 135, respectively, for the slider and journal bearing simulations. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE9000134000002 [...]