In the case of lid-driven deep cavity flow, the effects of different resolutions of local grid refinement have been studied in the frame of multiple relaxation times (MRT) lattice Boltzmann method (LBM). In all the ca...In the case of lid-driven deep cavity flow, the effects of different resolutions of local grid refinement have been studied in the frame of multiple relaxation times (MRT) lattice Boltzmann method (LBM). In all the cases, the aspect ratio and Reynolds number are set as 1.5 and 3.200, respectively. First, the applied method is validated by comparing it with two reported works, with which agreements are reached. Then, six separate degrees of local grid refinement at the upper left corner, i.e. purely coarse grid, including 1/64, 1/32, 1/16, 1/8, 1/4 refinements of the lattice number in the width direction have been studied in detail. The results give the following indications:① The refinement degrees lower than 1/8 produce similar results;② For single corner refinement, 1/4 refinement is adequate for clearing the noises in the singularity zone to a large extent;③ New noise around the interface between coarse and fine zones are introduced by local grid refinement. Finally, refinement of entire subzone neighboring the lid is examined to avoid introducing new noises and it has been found effective.展开更多
The lattice Boltzmann method is used to simulate the oscillating-grid turbulence directly with the aim to reproduce the experimental results obtained in laboratory. The numerical results compare relatively well with t...The lattice Boltzmann method is used to simulate the oscillating-grid turbulence directly with the aim to reproduce the experimental results obtained in laboratory. The numerical results compare relatively well with the experimental data through dete- rmining the spatial variation of the turbulence characteristics at a distance from the grid. it is shown that the turbulence produced is homogenous quasi-isotropic in case of the negligible mean flow and the absence of secondary circulations near the grid. The direct numerical simulation of the oscillating-grid turbulence based on the lattice Boltzmann method is validated and serves as the founda- tion for the direct simulation of particle-turbulence interactions.展开更多
基金Supported by Science and Technology Development Planning of Shandong Province,P.R.China(2016GGX104018)
文摘In the case of lid-driven deep cavity flow, the effects of different resolutions of local grid refinement have been studied in the frame of multiple relaxation times (MRT) lattice Boltzmann method (LBM). In all the cases, the aspect ratio and Reynolds number are set as 1.5 and 3.200, respectively. First, the applied method is validated by comparing it with two reported works, with which agreements are reached. Then, six separate degrees of local grid refinement at the upper left corner, i.e. purely coarse grid, including 1/64, 1/32, 1/16, 1/8, 1/4 refinements of the lattice number in the width direction have been studied in detail. The results give the following indications:① The refinement degrees lower than 1/8 produce similar results;② For single corner refinement, 1/4 refinement is adequate for clearing the noises in the singularity zone to a large extent;③ New noise around the interface between coarse and fine zones are introduced by local grid refinement. Finally, refinement of entire subzone neighboring the lid is examined to avoid introducing new noises and it has been found effective.
基金Project supported by the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(Grant No.51621092)the National Natural Science Foundation of China(Grant No.51579171)+1 种基金Tianjin Pro-gram of Applied Foundation and Advanced-Technology Re-search(Grant No.12JCQNJC04100)TH-1A supercompu-ter
文摘The lattice Boltzmann method is used to simulate the oscillating-grid turbulence directly with the aim to reproduce the experimental results obtained in laboratory. The numerical results compare relatively well with the experimental data through dete- rmining the spatial variation of the turbulence characteristics at a distance from the grid. it is shown that the turbulence produced is homogenous quasi-isotropic in case of the negligible mean flow and the absence of secondary circulations near the grid. The direct numerical simulation of the oscillating-grid turbulence based on the lattice Boltzmann method is validated and serves as the founda- tion for the direct simulation of particle-turbulence interactions.
