平面脉冲声波在多孔介质中传播的频移

利用传递函数，得到了平面脉冲声波在传播过程中任意位置处频谱的计算方法，用这种方法可以评价脉冲声波的主频偏移程度。给出了多孔介质中脉冲快纵波主频偏移的数值计算实例。计算结果表明，在一个有限的频带内，介质的声衰减与频率近似成线性关系，脉冲声波的主频偏移与介质的衰减、场点距声源的距离呈正比。该结果有利于利用脉冲声波的主频偏移来评价介质的声衰减

SHIFT OF CENTROID FREQUENCY OF PLANE ACOUSTIC PULSE PROPAGATION IN POROUS MEDIA

The formulas for calculating spectrum of plane acoustic pulses are obtained by using transfer function. These formulas can be used to evaluate the shift extent of centroid frequency of pulses. A numerical calculation for fast compressional pulse propagating in porous media is given. The example shows that in a narrow frequency band there is a linear relationship approximately between acoustic attenuation and frequency. The shift of centroid frequency of pulse is proportional to the acoustic attenuation and the distance of acoustic source and receiver. These results are useful for estimating acoustic attenuation by using the shift of basic frequency.