流体-孔隙介质周期性粗糙界面超声波反射与透射特性研究

为了研究超声波在流体-孔隙介质周期性粗糙界面的传播特性，文章基于周期性锯齿粗糙界面的衍射模型分析孔隙介质开孔与闭孔状态下孔隙度对反射与透射的影响。通过孔隙介质比奥特(Biot)理论与光栅方程理论，得到包含各阶反射系数、透射系数的线性方程组，再利用傅里叶变换进行数值计算，得到孔隙度与流体-孔隙介质周期性粗糙界面反射系数、透射系数之间的关系。结果表明，由于界面的周期性，频率对反射与透射系数的影响没有呈现一定的规律。但孔隙度对反射与透射系数有显著影响，且由于孔隙介质状态的差异性，导致反射与透射系数在开孔与闭孔时变化趋势不同。

Reflection and transmission characteristics of ultrasonic waves on the periodic rough interfaces between fluid and porous medium

The propagation characteristics of ultrasonic waves on the periodic rough interface between fluid and porous medium are studied, and the effect of porosity on reflection and transmission in the porous medium with open pores and sealed pores is analyzed. Based on Biot theory of porous medium and the grating equation theory, the linear equation including reflection coefficient and transmission coefficient of each order is obtained.. The relationships of porosity with reflection and transmission coefficients of the periodic rough interface are calculated by Fourier transform. The results show that the influence of frequency on the reflection and transmission coefficients is irregular due to the periodic characteristics of the interface. However, the variation of porosity has significant effect on reflection and transmission coefficients. Moreover, the coefficient changes are different in open pores and sealed pores because of the discrepancy in the porous medium states.