A comparative study of boundary conditions for lattice Boltzmann simulations of high Reynolds number flows
A comparative study of boundary conditions for lattice Boltzmann simulations of high Reynolds number flows
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DOI：
10.1016/j.compfluid.2017.06.008
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发表时间：
2017-10
影响因子：
2.8
通讯作者：
Kainan Hu;J. Meng;Hongwu Zhang;X. Gu;D. Emerson;Yonghao Zhang
中科院分区：
文献类型：
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作者：
Kainan Hu;J. Meng;Hongwu Zhang;X. Gu;D. Emerson;Yonghao Zhang
对格子Boltzmann模拟中常用的4种边界条件，即回弹边界条件、非平衡回弹边界条件、非平衡外推边界条件和动力学边界条件进行了系统的研究，以评价它们在模拟高雷诺数流动时的精度、稳定性和效率。对于经典的盖驱动空腔流动问题，研究发现，只要适当地施加边界条件以避免产生非物理滑移速度，反弹格式不会影响体区域的模拟精度。虽然动力学边界条件自然地在壁面产生物理滑移速度，但对于所考虑的雷诺数，它给出了中心线速度分布和涡中心位置的总体令人满意的预测。对于空腔流动问题，所有四种边界条件显示出达到稳定状态所需的计算时间的最小差异。这是令人惊讶的，因为动力学边界条件是显着不同的其他三个计划，这是专为无滑移边界条件。在边界点更新方面，反弹格式是计算效率最高的，如果流场中有大量的固体，这是特别有吸引力的。对于数值稳定性，我们进一步测试了有无封闭方柱的压力驱动槽道流。总的来说，动力边界条件是四种格式中最稳定的。非平衡外推格式对盖驱动空腔流动的稳定性仅次于动力学边界条件。与其它三种格式相比，非平衡反弹格式对两种流动的稳定性都不太令人满意。
Four commonly-used boundary conditions in lattice Boltzmann simulation, i.e. the bounce-back, non-equilibrium bounce-back, non-equilibrium extrapolation, and the kinetic boundary condition, have been systematically investigated to assess their accuracy, stability and efficiency in simulating high Reynolds number flows. For the classical lid-driven cavity flow problem, it is found that the bounce-back scheme does not influence the simulation accuracy in the bulk region if the boundary condition is properly implemented to avoid generating non-physical slip velocity. Although the kinetic boundary condition naturally produces physical slip velocity at the wall, it gives overall satisfactory predictions of the center-line velocity profile and the vortex center locations for the Reynolds numbers considered. For the cavity flow problem, all four boundary conditions show minimal difference in the computing time needed to reach a steady state. This is surprising because the kinetic boundary condition is significantly different from the other three schemes which are designed specifically for no-slip boundary conditions. The bounce-back scheme is the most computationally efficient in updating boundary points, which is particularly attractive if there are a large number of solid bodies in the flow field. For the numerical stability, we further test the pressure-driven channel flow with or without a enclosed square cylinder. Overall, the kinetic boundary condition is the most stable of the four schemes. The non-equilibrium extrapolation scheme presents excellent stability second to the kinetic boundary condition for the lid-driven cavity flow. In comparison with other threes schemes, the stability of non-equilibrium bounce-back scheme appears to be less satisfactory for both flows.