基于格子-波尔兹曼法的流体能耗求解

格子-波尔兹曼法是近年来新兴的一种计算流体力学数值方法。随着这种方法的不断发展,人们将它用于流体的仿真、优化等不同场合。与此同时,一些与流场流速和压强相关的物理量(如能耗)的求解也成为关注的焦点。本文介绍了能耗这一流体宏观量的格子-波尔兹曼法求解及其实现。与传统的有限差分法不同,本文在求解有关的速度梯度时使用了格子-波尔兹曼-矩法,这种方法不但能够避免有限差分法在边界处失效的缺点,而且计算简单,算法局部性好,适合大规模并行计算。本文在分析其数值解精度的基础上,使用这种方法进行了以能耗极小为目标的直通道内椭圆挡块的参数优化。这些分析和算例分别定量和定性地说明了本文算法的准确性。

Numerical evaluation of viscous energy dissipation of fluid using lattice Boltzmann method

The lattice Boltzmann method (LBM) is a new discrete numerical method to solve the fluid mechanics.As it develops,the method has been widely used in the numerical simulation and optimization of flows.Therefore,it is a straightforward requirement to evaluate the value of viscous dissipation of flow accurately with LBM.This paper presents a detailed procedure to calculate fluid viscous dissipation using the LBM.Other than the traditional finite difference method,the fluid viscous energy dissipation in this paper is solved by a lattice-Boltzmann-moment based approach.The moment based approach not only avoids the inapplicability that the finite difference method may have near the boundaries,but also works with a local algorithm which can be directly implemented on the high performance computers with the large-scale parallel computing techniques.Based on the precision analysis of this new numerical scheme,the optimization of an ellipsoid block in a straight channel flow is provided.The analysis and the example prove that the presented method is practically feasible and quantitatively valid.