NUMERICAL INSTABILITIES OF A LOCAL TRANSMITTING BOUNDARY
NUMERICAL INSTABILITIES OF A LOCAL TRANSMITTING BOUNDARY
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DOI：
10.1002/eqe.4290210105
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发表时间：
1992-01-01
影响因子：
4.5
通讯作者：
LIU, JB
中科院分区：
文献类型：
--
作者：
LIAO, ZP;LIU, JB
局部透射边界以紧凑的形式给出，可以直接并入有限元。 边界的准确性进行了深入的研究，以澄清数值不稳定性所引入的边界的一维模型。 在研究中严格考虑了模型的离散化和边界反射，然后通过边界反射的放大和有限计算区域内波动的多次反射在频域中阐明了不稳定性的机制。 简单模型的数值结果说明了时域不稳定性的典型特征，并从机理上给出了完整的解释。 在此基础上，对一维模型设计了一种修正的透射边界，并给出了其稳定性判据。
A local transmitting boundary is presented in a compact form, which can be directly incorporated into finite elements. The accuracy of the boundary is studied thoroughly for a one-dimensional model in order to clarify numerical instabilities introduced by the boundary. Discretization of the model and reflection from the boundary are rigorously considered in the study, and the mechanism of the instability is then illuminated in the frequency domain by the amplification of reflection from the boundary and the multi-reflection of wave motion in a finite computational region. Typical characteristics of the instability in the time domain are illustrated by numerical results of the simple model and explained completely by the mechanism. On the basis of this understanding of the mechanism, a modified transmitting boundary is devised and its stability criterion is given for the one-dimensional model.