Improvement of Grid Independence Test for Computational Fluid Dynamics Model of Building Based on Grid Resolution

Abstract

Computational fluid dynamics (CFD) is being used in various research fields on the building environment. Target space of the CFD model is divided into a finite number of grids for numerical analysis. Therefore, an optimal grid design is required to obtain accurate results. The grid independence test is generally performed to design an optimal grid. However, given that there is no standardized procedure for gird independence test, most depend on the researcher’s experience and knowledge. In the conventional method, the subjective judgment of the researcher affected the selection of the grid conditions and the criteria for the optimal grid. It can lead to a decrease in the reliability of the simulation results by poor grid design. This study proposed a grid independence test method that applies the grid resolution to improve the conventional method. The grid resolution was calculated by applying the characteristic length. CV(RMSE) and R2 were applied as the criteria for optimal grid. A case study was conducted to evaluate the adequacy of the proposed method. As the characteristic length increased, the optimal grid resolution increased. In particular, for a characteristic length of 0.7 or more, the optimal grid resolution was evaluated as 24. The grid convergence index (GCI) was calculated to verify the suitability of the proposed method. As a result, all of the optimal grid resolution derived from the proposed method was evaluated as the optimal condition.

Numerical Simulation of Combustion Characteristics in the Dome Zone of the COREX Melter-Gasifier: The Effect of Rising Gas

“…A mesh-independence test and model validation are conducted before the simulation. , Four different mesh resolutions with the cell numbers of 145 669, 195 606, 258 218, and 349 482 are adopted for the mesh independence analysis. Figure depicts the distribution of temperature along with the height of the central axis in the dome with different mesh resolutions.…”

Development of Building CFD Model Design Process Based on BIM

“…Grid independence test is conducted in most CFD studies, however there are no standardized methods or procedures for these tests [31]. In this respect, Lee et al [1] proffered and validated an improved grid independence test method by applying the grid resolution used in fire simulations.…”

“…The Levenshtein distance is the minimum number of single-character edits required to change two strings into the same data. The Levenshtein distance between a and b is calculated, as shown in Equation (1). In here, 1 (a i =b j ) is 1 when a i = b j and 0 when…”

“…Hexahedral grids were created with the same grid size for both conditions. The size of the grid was set as the optimal resolution by the characteristic length proffered in a study by Lee et al [1]. The optimal grid resolution was 24 because the characteristic length of all four targets was 0.7 or higher.…”

“…Computational fluid dynamics (CFD) is a fast and economic analysis method to analyze complex fluid flows through numerical analysis [1]. Computational Fluid Dynamics (CFD) enables various simulations related to the fluid flows of complex building shapes.…”