散阶

界面反射超声散斑一阶统计特性

First order statistical properties of the ultrasonic speckles reflected from an interface

得出该格式的数值耗散为二阶，数值频散为三阶。

It is found that the numerical dissipation is second order and the numerical dispersion is third order .

根据模拟计算结果发现，当地层中存在裂缝时，其瑞利导波频散曲线的基阶模式会出现截止或截断现象。

Simulation results show that , when there exists a fissure in the foundation , the first mode curve has a cut-off frequency or assumes an interceptive phenomenon .

首先通过变换，将程函方程化成一守恒形式；然后再差分离散，得到一阶和二阶精度的差分格式，并证明了差分格式条件稳定。

First , using some transformations , the authors obtain a conservation form from the Eikonal equation , and then not only give two types of finite difference schemes which have first order and second order accuracy respectively , but also prove that they are conditionally convergent .