Mengtao Han, Royzo Ooka, Hideki Kikumoto. Compressibility error of lattice Boltzmann method-based large eddy simulation with BGK model in indoor flows[C]//Proceedings of the 15th International Conference on Wind Engineering (ICWE15), Beijing, China, 2019.
发布时间：2021-03-10
点击次数：
- 论文类型：
- 论文集
- 发表刊物：
- Proceedings of the 15th International Conference on Wind Engineering (ICWE15)
- 刊物所在地：
- Beijing, China
- 学科门类：
- 工学
- 一级学科：
- 土木工程
- 文献类型：
- J
- 页面范围：
- 315-316
- 关键字：
- BGK model; Large-eddy simulation; Lattice Boltzmann method; compressibility errors; discrete time step; over-relaxation
- 发表时间：
- 2019-07-10
- 摘要：
- The lattice Boltzmann method-based large eddy simulation (LBM-LES), which is a new method to solve turbulence problems, has aroused widespread attention in recent decades. The Bhatnagar-Gross-Krook (BGK) approximation model, which is the most popular collision function for LBM, enables smooth recovery of the Navier-Stokes equation (NSE) from the lattice Boltzmann equation. However, the recovered NSE is compressible and employs additional terms related to the Mach (Ma) number. Thus, LBM-LES is inherently a pseudo-compressible method for solving the problem of incompressible fluids and generates the so-called “compressibility errors”. The compressibility errors include the deviations associated with the gradient of density and the deviations associated with Ma by the previous additional terms and velocity field divergence. In addition, in wind engineering, the collision step can exhibit the over-relaxation pattern, thus causing oscillation problems and degrading result accuracy, even though Ma and the gradient of density are not great. In this study, we discuss these errors by implementing an indoor isothermal forced convection benchmark case using the LBM-LES with the BGK model. The results indicate that different values of Ma that are controlled by the discrete time step δ in the LBM, affect the accuracy of the results significantly owing to compressibility errors. In particular, a large δ in coarse-grid resolutions produces obvious compressibility errors, while the errors can be compensated by scaling down δ. Meanwhile, an undersized δ leads to the turbulence fluctuations turning to numerical oscillations in the velocities owing to the over-relaxation of the distribution functions.
- 备注：
- 第15届国际风工程大会
- 上一条：Mengtao HAN, Ryozo Ooka, Hideki Kikumoto, Lattice Boltzmann Method integrated with large-eddy simulation applied to isothermal indoor flow (in Japanese), SEISAN KENKYU. 71 (2019) 23–28.
- 下一条：Mengtao Han, Royzo Ooka, Hideki Kikumoto. Comparison of Lattice Boltzmann Method and Finite Volume Method with Large Eddy Simulation in Isothermal Room Flow[C]//7th International Building Physics Conference (IBPC 2018):Healthy, Intelligent and Resilient Buildings and Urban Environments. Syracuse, New York: International Association of Building Physics (IABP), 2018: 1121–1126.