将一种常用的吸收边界条件─多次透射公式合并于紧接人工边界的内节点控制方程给出了该公式的一个新的实现方案.该方案较之原实现方案不仅收缩了计算区、改进了边界的模拟精度,而且揭示了该公式截断误差的阶数与大区域数值解之间的关系,阐明了提高吸收边界的精度阶对改进波动数值模拟精度的局限性.通过数值试验比较了新方案、原方案及Givoli-Neta吸收边界条件的在人工边界上的精度,结果表明前者优于后二者.
A implementiation scheme of the absorbing boundary conditions(ABCs) widely used—Multi-Transmitting Formula(MTF) is proposed by merging MTF into the governing equation of the interior nodes adjacent to the artificial boundary.Compared with the original scheme,the present one not only reduces the computational domain and improves the accuracy of boundary conditions,but also clearly reveals the relationship between the order of truncation error of the ABCs and the extended mesh solution which is commonly used as a benchmark to test ABCs.Limitation is then clarified for improving accuracy of numerical simulation of wave motion via increasing the accuracy order of an ABC.The performance of the present scheme,original one and Givoli-Neta ABC is finally compared via numerical examples concerning a semi-infinite wave guide.Results show that the first scheme is better than the other two.