MULTIPLE WAVES PROPAGATE IN RANDOM PARTICULATE MATERIALS
MULTIPLE WAVES PROPAGATE IN RANDOM PARTICULATE MATERIALS
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DOI：
10.1137/18m122306x
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发表时间：
2019-01-01
影响因子：
1.9
通讯作者：
Abrahams, I. David
中科院分区：
文献类型：
--
作者：
Gower, Artur L.;Parnell, William J.;Abrahams, I. David
70多年来，人们一直认为标量波在（整体平均）随机颗粒材料中的传播可以用单个有效波数来表征。然而，在这里，我们表明，存在许多有效波数，每个有效透射波场的贡献。大多数这些贡献迅速衰减远离边界，但他们作出了显着的贡献，反射和总透射场超出了低频制度。在某些情况下，至少两个有效波数具有相同的衰减阶数。在这些情况下，一个单一的有效波数不能准确地描述波的传播，即使远离边界。我们开发了一种有效的方法来计算所有的贡献，在两个空间维度的标量波方程的波场，然后比较结果与数值有限差分计算。据作者所知，这种新方法是第一种在很宽的频率范围内和一般颗粒体积分数上给出如此准确的预测的方法。
For over 70 years it has been assumed that scalar wave propagation in (ensemble-averaged) random particulate materials can be characterized by a single effective wavenumber. Here, however, we show that there exist many effective wavenumbers, each contributing to the effective transmitted wave field. Most of these contributions rapidly attenuate away from boundaries, but they make a significant contribution to the reflected and total transmitted field beyond the low-frequency regime. In some cases at least two effective wavenumbers have the same order of attenuation. In these cases a single effective wavenumber does not accurately describe wave propagation even far away from boundaries. We develop an efficient method to calculate all of the contributions to the wave field for the scalar wave equation in two spatial dimensions, and then compare results with numerical finite-difference calculations. This new method is, to the best of the authors' knowledge, the first of its kind to give such accurate predictions across a broad frequency range and for general particle volume fractions.