scholarly journals A Multi-Relaxation-Time Lattice Boltzmann Method on Non- Uniform Grids for Large Eddy Simulation of Rayleigh-Bénard Convection Using Two Sub-Grid Scale Models

2014 ◽  
Vol 7 (01) ◽  
Author(s):  
Md Jahidul Haque ◽  
Md Mamun Molla ◽  
Md Amirul Islam Khan ◽  
Kamrul Ahsan

In this present study, three-dimensional lattice Boltzmann method is implemented with the popular turbulence modeling method large-eddy simulation incorporating three different non-dynamic sub-grid scale models Smagorinsky, Vreman, and wall-adapting local eddy-viscosity for finding the inhomogeneous turbulent airflow patterns inside a model room with a partition. The large eddy simulation-lattice Boltzmann method code is validated with the experimental results of Posner’s model, where the model room having one partition at the bottom, one inlet, an outlet placed at top wall considered for the comparisons. The lattice Boltzmann method code is also validated without any sub-grid scale model with the results of lid-driven flow in a cubic cavity. The present numerical simulations are performed by the graphics process unit accelerated parallel programs using compute unified device architecture C platform. Double precession capable a Tesla k40 with 2880 compute unified device architecture cores NVIDIA graphics process unit card has been used for these simulations. Graphics processor units have gained popularity in recent years as a propitious platform for numerical simulation of fluid dynamics. In fact, faster computational task performance in graphics process units is one of the key factors for researchers to choose graphics process unit over conventional central processing units for the implementation of data-intensive numerical methods like lattice Boltzmann method. The effects of the sub-grid scale model have been evaluated in terms of the mean velocity profiles, streamlines as well as turbulence characteristics and found that there are significant differences in the results due to the different sub-grid scale models.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Lei Xu ◽  
Anping Song ◽  
Wu Zhang

The lattice Boltzmann method (LBM) has become an attractive and promising approach in computational fluid dynamics (CFD). In this paper, parallel algorithm of D3Q19 multi-relaxation-time LBM with large eddy simulation (LES) is presented to simulate 3D flow past a sphere using multi-GPUs (graphic processing units). In order to deal with complex boundary, the judgement method of boundary lattice for complex boundary is devised. The 3D domain decomposition method is applied to improve the scalability for cluster, and the overlapping mode is introduced to hide the communication time by dividing the subdomain into two parts: inner part and outer part. Numerical results show good agreement with literature and the 12 Kepler K20M GPUs perform about 5100 million lattice updates per second, which indicates considerable scalability.


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