基于浸没边界和格子玻尔兹曼的流固耦合算法

Fluid-structure interaction method using immersed boundary and lattice Boltzmann method

为将格子玻尔兹曼方法(LBM)用于土木工程结构的气动弹性计算,提出了一种基于浸没边界-格子玻尔兹曼(IB-LB)方法的流固耦合算法.该算法在多松弛时间格式的格子玻尔兹曼框架下构造大涡模拟作为流场求解器;采用龙格-库塔法求解结构运动方程.为满足流固耦合面的无滑移性并提高算法的计算精度,采用一种迭代格式的浸没边界实施流固耦合面的数据交换.基于流固耦合算法编制分析程序对矩形断面的横向风振和福斯桥的颤振等气动弹性问题进行了模拟.与现有试验及数值结论的对比分析表明:本文算法可以较准确地预测矩形断面的涡振锁定风速、驰振临界风速及福斯桥的颤振临界风速.

In order to apply lattice Boltzmann method（LBM）to aeroelastic analyses of the civil structures,a fluid-structure interaction（FSI）algorithm based on immersed boundary-lattice Boltzmann（IB-LB）method was presented in this paper.In the present algorithm,large eddy simulation was developed within the framework of multiple relaxation time lattice Boltzmann method to model the flow past the bluff body,and the Runge-Kutta method was used to solve the structural motion equations.In addition,an implicit IB method was adopted to implement the fluid-structure interface to satisfy the no-slip condition and improve the accuracy of the FSI algorithm.The aeroelastic simulations of a rectangular cylinder and the Forth Road Bridge were performed using self-developed codes.The results show that the lock-in phenomenon of vortex-induced vibration and the critical galloping velocity captured by the present algorithm for the rectangular cylinder are in good agreement with experimental data.Meanwhile,the study reveals that the present algorithm has a good prediction for the flutter onset velocity of the Forth Road Bridge.