浅海低频声场的水平纵向相关性

Horizontal-longnitudinal correlations of low-frequency acoustic field in shallow water

基于一次浅海声学实验数据,研究了浅海低频声场的水平纵向相关特性。利用简正波干涉理论,对实验结果中声场水平纵向相关的振荡结构与强烈起伏现象进行了分析与解释。声场水平纵向相关的振荡结构是由简正波干涉所致,该实验结果进一步验证了该现象在浅海低频条件下的普遍性。当实验中采用的爆炸声源的标称深度位于声场中某号有效简正波的一个波节附近,声源实际爆炸深度的较小变化引起该号与其它号有效简正波幅度比值的较大变化,从而在有效简正波号数较少的情况下引起了声场水平纵向相关的强烈起伏现象,该现象表明在一定条件下声源深度是浅海低频声场水平纵向相关的一个敏感参数。

The horizontal-longitudinal correlations of low-frequency acoustic field in shallow water are inv-estigated based on experimental data.The oscillation pattern and strong fluctuations of the horizontal-long-itudinal correlations observed in the experiments are analyzed and interpreted by using the normal modes interference theory.The oscillation pattern is induced by normal modes interference,and the generality of this phenomenon for low-frequency acoustic field in shallow water is further verified by experiments.When the preset depth of the explosive source detonated is close to a node of a valid normal mode＇s eigenfunction,small variations of the actual source depths can lead to significant variations of the ratios of the amplitude of that normal mode to the amplitudes of other valid normal modes.Therefore,small vari-ations of the source depths lead to strong fluctuations of the horizontal-longitudinal correlations under the condition that there are relatively small number of valid normal modes in the acoustic field,and the phen-omenon show that source depth is a sensitive parameter of the horizontal-longitudinal correlations of low-frequency acoustic field in shallow water under certain conditions.