A Computational Simulation of Steady Natural Convection in an H-form Cavity

15 pages, 5 figures, 1 table, 34 references. Other papers can be downloaded at http://www.denys-dutykh.com/International audienceThe simulation of natural convection problem based on the Galerkin finite-element method, with the penalty finite-element formulation of the momentum balance equation, is exploited for accurate solutions of equations describing the problem of H-Form cavity differentially heated side walls. The cavity is occupied by the air whose Prandtl number is Pr=0.71, the fluid is assumed to be steady, viscous and incompressible within thermal convection. A numerical investigation has been made for Rayleigh numbers ranging from 10 to 10^6 for three cases of total internal height aspects of H-Form cavity: 0%, 50%, and 85%. Firstly, the goal is to validate the numerical code used to resolve the equations governing the problem of this work. For that, we present a comparison between the profiles at the point (0.5, 0) for the u-component, and u-component obtained in previous work for simple square cavity. Further, a comparison of the averaged Nusselt number with previous works for simple square cavity is realized in order to ensure the numerical accuracy, and the validity of our considered numerical tool. Secondly, the objective is to investigate on the hydrodynamic effects of Rayleigh number for different total internal height aspects of H-Form cavity on the dynamics of natural convection. Shortly after, the ambition is to assess the heat transfer rate for different Rayleigh number for three cases of internal height aspects

Combining grey relation analysis and entropy model for evaluating the operational performance: an empirical study

[[abstract]]Decision-making on operational performance evaluation is a complex multi-objective problem. Through the combination of grey relation analysis and information entropy, the evaluation results are more objective and reasonable. This paper would introduce entropy into the weighting calculation of the grey relational analysis method for improving the precision. The improved decision model was applied in four notebook computer original design manufacturer companies. The result presented the proposed method is practical and useful. Significantly, the proposed method provides more flexible and objective information in determine the weights vector of the criteria. Also the study result represented that the combined method had certain scientific and rationality. The evaluation model indicates that this method be more reasonable and easier to grasp than other methods. As a result, it is easier to popularize this evaluation method in enterprises.[[journaltype]]國外[[incitationindex]]SSCI[[ispeerreviewed]]Y[[booktype]]電子版[[countrycodes]]NL