海底沉积物参数对浅海中低频声传播的影响

Effects of sediment parameters on the low frequency acoustic wave propagation in shallow water

推导出了考虑海底沉积物中声衰减和横波后浅海中点声源激发声场的积分表达式，并用实轴积分法和快速傅里叶交换（ＦＦＴ）数值计算模拟了爆炸声源在浅海中激发的全波列波形。考察了海底沉积物参数、声源激发主频等对低频声传播的影响。研究表明：在远场接收到的波群为声源主频处的模式波。最后讨论了通过几个不同声源激发主频处的某一模式波的群速度的测量值用最小平方和估计法来反演海底沉积物的纵波速度和横波速度的可能性。

We have derived the integral expression for acoustic held due to a point source in shallow water while sediment is either a liquid or a solid. The synthetic full waveforms are simulated using real axis integration and FFT method. The effects of the sea sediment parameters and center frequency of the source on the low frequency acoustic wave propagation in shallow water are investigated. We may draw a conclusion that the wave groups received in far field are those of the mode waves of the center frequency of source. Finally we have discussed the possibility for inversely deducing the compressional and shear sound speeds of a sediment using the least square optimum through the measured group velocities of a selected mode at different frequencies.