| 周正华,魏景芝,王玉石,王伟,丁桦.修正算子γB00的物理含义及精度分析[J].计算力学学报,2011,28(1):20~24 |
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| 修正算子γB00的物理含义及精度分析 |
| The physical implication and the precision analysis of modified operator γB00 |
| 投稿时间：2009-02-23 修订日期：2010-05-24 |
| DOI：10.7511/jslx201101004 |
| 中文关键词: 球面波 阻尼效应 修正算子 多次透射公式 反射系数 |
| 英文关键词:spherical wave damping effect modified operator multi-transmitting formula reflection coefficient |
| 基金项目:国家自然科学基金重大研究计划(90715038);973项目(2002CB412706);中国地震局工程力学研究所中央级公益性研究所基本科研业务费专项(2006A02);地震行业科研专项(200808019)资助项目. |
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| 中文摘要: |
| 多次透射公式是一种用于无限介质波动数值模拟中的局部人工边界条件,飘移失稳是多次透射公式在时步积分数值模拟实现中出现的一种失稳现象,可通过在多次透射公式算子中加上修正算子γB00的简便处理方法消除。本文依据球面波传播原理和介质阻尼效应解释了修正算子γB00的物理含义,并在两种极限情形(理想暂态情形和理想稳态情形)下对加修正算子γB00的多次透射公式的反射系数进行了推导,分析了γ取值对多次透射公式反射系数的影响。结果表明:加修正算子γB00的多次透射公式在波动数值模拟中考虑了介质的几何扩散特性,或引入了介质的阻尼特性;当γ≤0.02时,修正算子γB00对多次透射公式反射系数的影响可忽略不计。 |
| 英文摘要: |
| The Multi-Transmitting Formula (MTF) is a local artificial boundary condition used for numerical simulation of the wave motion in infinite media. The drift instability is one type of the numerical instabilities in implementation of MTF into the numerical simulation by time-step integration, and may be eliminated by a simple measure, namely, adding a modified operator γB00 into the operator of MTF. The physical implication on modified operator γB00 of MTF is interpreted based on the theory of spherical wave propagation and damping effect of medium. In addition, the reflection coefficient of MTF added modified operator γB00 in two limit cases (ideal transient case and ideal steady-state case) is derived, and the influence of γ-value on this is analyzed. Results show that MTF added modified operator γB00 used for numerical simulation of the wave motion takes geometric decay effect of medium into account, or introduces damping effect of medium, and if γ≤0.02, the effect of modified operator γB00 on the reflection coefficient of MTF may be ignored. |
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