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Analyzing grid independency and numerical viscosity of computational fluid dynamics for indoor environment applications
Abstract Computational fluid dynamics (CFD) has been introduced to indoor environment study for decades. Analysis of CFD results will first require the reach of a grid-independent CFD solution to eliminate the false information induced by numerical causes, e.g., grid and numerical scheme. Judging a grid-independent solution has been mostly experience-based, leading the necessity of developing an objective and easy-to-use criterion for grid independency evaluation. This paper presents a new approach to assessing the grid independency of CFD modeling for indoor environment applications. A normalized root mean square error (RMSE) index is developed from the grid convergence index (GCI) concept in literature to evaluate the overall differences of predicted results with varying grid resolutions. The paper further introduces the use of numerical viscosity analysis method to verify the grid-independent solution of a CFD analysis, which also provides fundamental insight into the grid-induced error in numerical solutions. Although initially developed for indoor environment applications, the proposed RMSE index along with the numerical viscosity analysis method can be applied to most general CFD studies and has great potential of being incorporated into commercial CFD software to provide user a more accurate and objective alternative of checking grid independency of CFD simulation.
Highlights ► Develop a single index for evaluating grid independency of CFD predictions. ► Propose numerical viscosity analysis method to verify grid independency of CFD predictions. ► Demonstrate the application of the proposed method for indoor environment modeling.
Analyzing grid independency and numerical viscosity of computational fluid dynamics for indoor environment applications
Abstract Computational fluid dynamics (CFD) has been introduced to indoor environment study for decades. Analysis of CFD results will first require the reach of a grid-independent CFD solution to eliminate the false information induced by numerical causes, e.g., grid and numerical scheme. Judging a grid-independent solution has been mostly experience-based, leading the necessity of developing an objective and easy-to-use criterion for grid independency evaluation. This paper presents a new approach to assessing the grid independency of CFD modeling for indoor environment applications. A normalized root mean square error (RMSE) index is developed from the grid convergence index (GCI) concept in literature to evaluate the overall differences of predicted results with varying grid resolutions. The paper further introduces the use of numerical viscosity analysis method to verify the grid-independent solution of a CFD analysis, which also provides fundamental insight into the grid-induced error in numerical solutions. Although initially developed for indoor environment applications, the proposed RMSE index along with the numerical viscosity analysis method can be applied to most general CFD studies and has great potential of being incorporated into commercial CFD software to provide user a more accurate and objective alternative of checking grid independency of CFD simulation.
Highlights ► Develop a single index for evaluating grid independency of CFD predictions. ► Propose numerical viscosity analysis method to verify grid independency of CFD predictions. ► Demonstrate the application of the proposed method for indoor environment modeling.
Analyzing grid independency and numerical viscosity of computational fluid dynamics for indoor environment applications
Wang, Haidong (author) / Zhai, Zhiqiang (John) (author)
Building and Environment ; 52 ; 107-118
2011-12-23
12 pages
Article (Journal)
Electronic Resource
English
| British Library Online Contents | 2012