声学FDTD法完全匹配层数和衰减系数对衰减性能的影响

Attenuation Ability Influenced by Amount and Attenuation Coefficient of Perfectly-Matched Layers in Acoustic FDTD Method

分析了声学时域有限差分(FDTD)法中完全匹配层(PML)层数、衰减系数对吸收效果的影响.通过建立研究PML边界吸收性能的模型发现:PML边界层层数和衰减系数的选择相互关联;边界层数越多,PML的吸收效果越好,但计算量增大;层数一定时,需要为各衰减层设置合适的衰减系数,以减少衰减系数差异带来的数值反射;在实际计算中,应综合考虑计算量和计算精度,给出这些参数的合理设置值.

This paper deals with the acoustic absorbing ability affected by the amount and attenuation coefficient of perfectly-matched layers（PML） in acoustic finite-difference time-domain（FDTD） method,and establishes a PML boundary model for the absorbing ability analysis.The results indicate that（1） the layer amount and the attenuation coefficient relate to each other;（2） more PML layers may result in high absorbing ability but heavy computation burden;（3） when the layer amount is unchanged,appropriate attenuation coefficient should be set for each attenuation layer for the purpose of decreasing the numerical reflection due to the difference in attenuation coefficient;and（4） in practical applications,suitable layer amount and attenuation coefficient should be determined by comprehensively considering the calculation complexity and accuracy.