A numerical study of algebraic flux models for heat and mass transport simulation in complex flows

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• 作者：Riccardo Rossi
• 关键词：Scalar transport ; Complex flows ; RANS ; Eddy-diffusivity ; Algebraic flux models
• 刊名：International Journal of Heat and Mass Transfer
• 出版年：2010
• 出版时间：October 2010
• 年：2010
• 卷：53
• 期：21-22
• 页码：4511-4524
• 全文大小：779 K

文摘

A numerical study of heat and mass transport based on the Reynolds-Averaged Navier–Stokes and scalar transport equations is presented to establish the predictive capabilities of algebraic flux models compared to the standard eddy-diffusivity representation. The analysis of scalar transport in simple-shear flows is initially performed to provide a basic validation of numerical techniques and scalar flux closures. The evaluation of algebraic models is carried out by examining the flow and scalar transport phenomena over a wavy wall and comparing the results to reliable direct numerical simulations. Despite the similarities with the standard gradient-diffusion hypothesis and the questionable validity of local-equilibrium conditions, the results show that algebraic models provide an efficient way to improve heat and mass transport predictions in complex flows with respect to the standard eddy-diffusivity model. The impact of abandoning the isotropic eddy-diffusivity in favor of a tensorial representation is found particularly significant in the analysis of scalar dispersion from a point source over the wavy wall, where lateral transport comes into play. While it is found that algebraic closures also represent a reasonable approximation for the spanwise scalar flux, the lateral spread of scalar concentration is considerably under-estimated by the standard gradient-diffusion model.