Numerical Investigation of Lid-Driven Deep Cavity with Local Grid Refinement of MRT-LBM

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.

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) Newnoise 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 newnoises and it has been found effective.