摘要
利用2020年6月海南岛沿岸试验数据,分析内波及声能量起伏特征。试验海域以全日潮内波为主,并伴随有高频内波活动。内波活动引起360 Hz单频信号20 km定点声起伏峰峰值超过30 dB,320~400 Hz线性调频信号起伏峰峰值超过15 dB。利用测量数据结合数值仿真,讨论了内波引起单频信号和线性调频信号呈现不同起伏特征的原因。结果表明:试验海域内波活动导致单频声场模态间干涉条纹出现移动,进而导致接收位置处特定频率的声能量出现大幅度的快速起伏;由于带宽内的平均作用,宽带信号的能量起伏远小于单频信号的能量起伏。当内波传播速度变化时,各内波成分在声传播路径上出现的时间和位置发生了变化,使得声场出现剧烈起伏的时间也随之变化。
The characteristics of internal waves and acoustic-energy fluctuations are analyzed by the experimental data from the coast of Hainan Island in China in June 2020.Internal waves with a diurnal tide period dominate the experimental sea area,accompanied by high-frequency internal-wave activities.Owing to internal-wave activities,the peak-to-peak value of the energy fluctuations of 360 Hz continuous wave signals at 20 km exceeds 30 dB and that of 320–400 Hz linear frequency modulation signals exceeds 15 dB.The reasons for different fluctuation characteristics of continuous wave signals and linear frequency-modulated signals are discussed based on the experimental measurements and numerical simulation of acoustic field.The results show that the internal-wave activities in the experimental sea area can move the interference stripes between acoustic normal modes,leading to the rapid fluctuations of sound energy at a specific frequency at the receiving location.The energy fluctuations of broadband signals are much smaller than those of single-frequency signals because of the averaging effect of bandwidth.When the propagation velocity of internal waves changes,the time and position of internal-wave components along the sound propagation path change,varying the time of rapid fluctuations in the sound field accordingly.
作者
王臻
胡涛
王文博
郭圣明
马力
WANG Zhen;HU Tao;WANG Wenbo;GUO Shengming;MA Li(Key Laboratory of Underwater Acoustic Environment,Institute of Acoustics,Chinese Academy of Sciences,Beijing 100190;University of Chinese Academy of Sciences,Beijing 100049)
出处
《声学学报》
EI
CAS
CSCD
北大核心
2024年第1期67-77,共11页
Acta Acustica
关键词
浅海内波
声能量起伏
声传播
模态分析
Shallow-water internal waves
Acoustic-energy fluctuation
Acoustic propagation
Modal analysis
