【摘要】 在地震波场数值模拟中,为了消除由人为边界产生的边界反射,需要引进边界吸收条件。本文从声波方程完全匹配层吸收边界的经典方法出发,基于高斯函数任意阶光滑的特点,提出了一种高斯型衰减因子,分析比较该因子与一般衰减因子的性质,并基于均匀与层状速度模型分别进行了数值模拟计算。数值结果显示,当选择相同的PML边界吸收层层数时,高斯型衰减因子的吸收效果明显优于一般的衰减因子,边界反射更少,信噪比更高;对比最近提出的正弦型衰减因子,在信噪比接近的情况下,高斯型衰减因子所需的PML吸收层层数更少。更多还原

【Abstract】 When simulating seismic wave propagation in free space, it is essential to introduce absorbing boundary conditions to eliminate reflections from artificially truncated boundaries. In this paper, a damping factor referred to as the Gaussian damping factor is proposed. The Gaussian damping factor is based on the idea of perfectly matched layers (PMLs). This work presents a detailed analysis of the theoretical foundations and advantages of the Gaussian damping factor. Additionally, numerical experiments for the simulation of seismic waves are presented based on two numerical models: a homogeneous model and a multi-layer model. The results show that the proposed factor works better. The Gaussian damping factor achieves a higher Signal-to-Noise Ratio (SNR) than previously used factors when using same number of PMLs, and requires less PMLs than other methods to achieve an identical SNR.更多还原