散射问题中消除多次透射边界高频振荡失稳措施比较分析  

Comparison of Measures for Eliminating High-frequency Instability of a Multi-transmitting Boundary in Scattering Problems

作　　者：杨宇[1,2] 李小军[2] 贺秋梅[2] 王璐[1] 

机构地区：[1]环境保护部核与辐射安全中心,北京100082 [2]中国地震局地球物理研究所,北京100081

出　　处：《地震工程学报》2014年第3期476-481,共6页China Earthquake Engineering Journal

基　　金：国家重点基础研究发展计划(2011CB013601);环保公益项目(201309056);国家自然科学基金重大研究计划(91215301)

摘　　要：多次透射边界是一种应用广泛的人工边界,类似于其它局部人工边界,它也存在计算稳定性问题。本文分析多次透射边界高频振荡失稳的原因,通过数值试验对已有的消除高频失稳措施进行比较分析,并给出在散射问题中已有消除高频失稳措施的适用性。研究表明,对于完全弹性问题,建议用滤波方法消除高频振荡失稳,但滤波系数的取值需要依据一定的经验;对于黏弹性问题,建议适当控制阻尼取值,利用差分格式本身的高能耗特性来抑制高频振荡失稳,该方法不存在参数选取的问题,更便于应用实施。The multi-transmitting boundary is a local artificial boundary widely used in the numer-ical simulation of near-field wave motions in infinite media.But,like other artificial boundaries, the multi-transmitting boundary is unstable in numerical simulations.In this paper,we analyze the cause of this high-frequency instability and discuss the applicability of previous stability measures by performing numerical scattering problem experiments.We found that（1）for the perfect elastic-ity problem,the filtering method is more suitable for eliminating high-frequency instability,but it must be used carefully because of the need to consider the empirical value of the parameters;and （2）for the viscoelastic problem,the explicit difference scheme with a suitable damping value is more suitable for eliminating high-frequency instability due to the energy dissipation of the differ-ence scheme.This scheme is also more convenient for application because no empirical parameters must be considered.

关 键 词：散射 多次透射边界 高频震荡失稳 滤波 高频能耗性 

分 类 号：P315.9[天文地球—地震学] TU43[天文地球—固体地球物理学]