浅海中声源激发的Scholte波频率特性研究

A study on frequency characteristics of scholte wave excited by sound sources in a shallow sea

为了研究Scholte波能量集中在甚低频段的特性。基于浅海声场模型,利用高阶交错网格有限差分算法,仿真分析了硬海底和软海底条件下Scholte波的幅度与声源频率之间的关系。结果表明:两种海底条件下Scholte波的幅度均随声源频率增加而逐渐减小;开展海上气枪和货轮激发Scholte波的试验,气枪试验分析结果表明:Scholte波受声源频率影响较大,声源频率越高越不利于激发产生Scholte波;货轮试验分析结果表明:Scholte波的能量主要集中在10~25 Hz,频域特征稳定,传播距离远、衰减慢,当货轮由远及近航行时Scholte波能量由弱变强,呈现与货轮航行状态相符的变化趋势。

In order to study the characteristics of Scholte wave energy concentration in very low frequency band,based on the acoustic field model in a shallow sea,the relationship between the amplitude of Scholte wave and the frequency of sound source under the conditions of hard seabed and soft seabed was simulated and analyzed by using the high-order staggered grid finite difference method.The results show that the amplitude of Scholte wave decreases gradually with the frequency of the sound source under both seabed conditions.Experiments on Scholte wave excitation by air gun and freighter at the sea were carried out.The results of the air gun test show that Scholte wave is greatly influenced by the frequency of sound source,the higher frequency of the sound source,the more unfavorable it is to excite the Scholte wave.The results of freighter test show that the energy of Scholte wave is mainly concentrated in 10—25 Hz,the frequency domain characteristics are stable,the transmission distance is long and the attenuation is slow.When the freighter is sailing far to near,the energy of Scholte wave increases from weak to strong,showing a trend consistent with the state of freighter navigation.