桥梁断面静风荷载的格子Boltzmann方法数值计算

Numerical assessment of static wind loads on bridge deck section based on lattice Boltzmann method

通过引入反映湍流涡粘性的湍流松弛,得到了模拟高雷诺数湍流的BGK方程。在速度相空间、物理空间和时间上对BGK方程进行离散得到了三维十九速离散速度模型;结合分区计算技术,设计了格子Boltzmann并行算法;根据亚格子Smagorinsky模型,提出了直接从粒子分布函数计算湍流松弛时间的方法。用开发的并行计算程序对分体双箱截面和闭口箱梁截面的静风荷载进行了数值识别,得到的静力三分力系数和流场压力分布与风洞试验结果及CFD宏观方法计算结果吻合,并从表面压力分布入手分析了两种桥梁截面的绕流特点。

The BGK equation is derived to simulate turbulence flow at high Reynolds number with the turbulence relaxation time represented the turbulence vicious, and it is discretized to three-dimension nineteen velocities model with discrete velocity, space step and time step. The lattice Boltzmann parallel arithmetic is designed combining with field partitioning technique. Otherwise, the turbulence relaxation time is computed directly from particle distribution function according to subgrid Smagorinsky model. The static wind loads on twin-box section and closed-box section are identified by present method. The static three-component forces and distribution of pressure agree well with that of wind tunnel experiments and other macro- scopical CFD method. Finally, the flows around these bridge deck sections are researched from the point of distribution of surface pressure.