- GAO Yan;SHEN Qi;YU Mengsa;LIU Jin;WU Bo;
The measurements for transition frequency-space spectrum and its spectral peak characteristics, turbulent wall pressure fluctuation and its similarity are conducted in acoustic wind tunnel through embedded flush-mounted flexible sensor arrays, regarding two large-scale revolution body models. The numerical fitting model of wall pressure fluctuation in the transition and turbulent regions can be established, in which Reynolds number can serve as frequency segmentation point, and the model is characterized by universality to some extent. It is showed that the local Reynolds number in the transition region at the bow of revolution body is 5.27×10~5-1.1×10~6, and the wall pressure fluctuation within the frequency range of transition characteristic spectrum increases by 36 dB from the initial to the fully developed transition stage. Besides, non-dimensional central frequency of transition characteristic spectrum is essentially unchanged at 0.2. The non-dimensional fluctuation pressure spectrum in the turbulent region is in the range of 0.1-10, which is in accordance with that of Smol’yakov model. In addition, the non-dimensional spectrum of turbulent fluctuation pressure has scale effects of 3-4 d B in the ranges of 0.4-4 for the same model, while it has scale effects of 4 d B in the ranges of 0.1-10 for different scale models, in which the non-dimensional spectrum increases by enlargement of the model.
2025年02期 v.44 103-119页 [查看摘要][在线阅读][下载 4420K] [阅读次数：3 ] |[下载次数：1 ] |[引用频次：0 ] - ZHANG Jiali;ZHAO Shuang;WANG Zhenjie;
This paper presents a method combining B-splines and autoregressive moving averages for the joint correction of sound velocity disturbances, addressing the problem of existing parameterized models for sound velocity errors in underwater geodetic positioning without considering the temporal correlation of sound velocity disturbances. Initially, a quadratic polynomial and a cubic B-spline model are utilized to preliminarily correct the disturbed sound speed structure. Subsequently, considering temporal correlation variations, sound speed error processing is conducted based on the autoregressive moving average model. Finally, the method is validated using data from the 3000-meter sea trial in the South China Sea. The results indicate that, compared to the quadratic polynomial and cubic B-spline sound speed corrections, applying the autoregressive moving average model for successive sound speed correction reduces the root mean square error of time observation value residuals by 58%and 30%, respectively.
2025年02期 v.44 120-134页 [查看摘要][在线阅读][下载 4240K] [阅读次数：3 ] |[下载次数：6 ] |[引用频次：0 ] - JI Guihua;REN Yun;WU Qingtian;ZHANG Zhenzhou;LIANG Heng;JIANG Zijin;
The horizontal-longitudinal correlation of the sound field decreases rapidly in the shadow zone of the deep sea, which severely limits the detection performance of the horizontal array in this area. This paper employs a range-frequency interference structure to frequency-shift compensate the acoustic field at different longitudinal intervals to improve the horizontal-longitudinal correlation of the acoustic field in the shadow zone. Firstly,the range-frequency interference structure and the horizontal-longitudinal correlation are analyzed by simulation based on a deep-sea experimental environment, and the simulated horizontal-longitudinal correlation of the acoustic field is improved through frequency-shift compensation by using an equivalent waveguide invariant. Then the experimental acoustic data from the deep-sea experiment is analyzed. The horizontal-longitudinal correlation of the received acoustic field in the first shadow zone at three depths and two ranges is processed. The data processing results show that the horizontal-longitudinal correlation length after frequency-shift compensation is increased by approximately 4 to 11 times compared to before the frequency-shift compensation. The simulated and experimental results demonstrate that the use of a range-frequency interference structure for frequency-shift compensation of the received acoustic field can effectively improve the horizontal-longitudinal correlation of the sound field in the shadow zone of the deep sea.
2025年02期 v.44 135-152页 [查看摘要][在线阅读][下载 4710K] [阅读次数：3 ] |[下载次数：0 ] |[引用频次：0 ] - LAN Shuyao;LI Yu;ZHANG Chunhua;CHI Cheng;CHEN Chunhui;
While using the bottom bounce mode to detect deep-sea shadow zone, the signal-to-noise ratio decreases due to the influence of the seabed reflection loss on the signal, which poses great difficulties for target detection. Therefore, this article establishes a signal model based on the propagation law of sound in deep-sea shadow zone and analyzes the multipath structural characteristics of signals in shadow channels. Based on the principle of generalized likelihood ratio test, the detector suitable for target detection in shadow zone is designed according to the single beam multipath structural characteristics and spatial beam splitting characteristics. The simulation results and real data processing results both indicate that the proposed detector has significantly improved detection performance compared to traditional matched filter detectors by extracting and utilizing the multipath structural features of the echo of the shadow zone.
2025年02期 v.44 153-168页 [查看摘要][在线阅读][下载 1500K] [阅读次数：3 ] |[下载次数：1 ] |[引用频次：0 ] - ZHANG Zheming;HAN Xiao;GE Wei;YANG Shuyun;YIN Jingwei;
To tackle the challenge where existing estimation algorithms exhibit performance deterioration or complete failure in polar environments due to impulsive noise, this paper presents a robust orthogonal matching pursuit(OMP) algorithm. Firstly, accurate selection of atom bases is achieved by introducing the maximum correntropy criterion(MCC). Secondly, the L1norm is utilized to reconstruct the loss function, mitigating the influence of impulse noise on parameter estimation. Simultaneously, the alternating direction method of multipliers(ADMM) is employed to efficiently obtain the global optimal solution. Numerical simulations and the processing of experimental data collected from the9th Chinese National Arctic Research Expedition have shown that the proposed method exhibits significant performance improvements compared to classical algorithms. Specifically, it exhibits higher estimation accuracy and stronger robustness under impulsive noise conditions.
2025年02期 v.44 169-190页 [查看摘要][在线阅读][下载 2098K] [阅读次数：3 ] |[下载次数：1 ] |[引用频次：0 ] - LV Chenglei;WU Xintao;CHEN Huifang;XIE Lei;
Based on the stable multipath structure characteristics of the under-ice acoustic channel, a scheme utilizing the preamble signal of the communication frame for channel estimation is adopted. Leveraging the sparse characteristics of the under-ice acoustic channel, an adaptive sparsity orthogonal matching pursuit(ASOMP) algorithm is proposed to address the reliance of the orthogonal matching pursuit(OMP) algorithm on prior knowledge of sparsity. Firstly, the sparsity of the channel is coarsely estimated using the autocorrelation characteristics of the preamble signal, and the simplified dictionary matrix is constructed. Subsequently, based on the coarsely estimated sparsity and the simplified dictionary matrix, the OMP algorithm is employed to obtain a preliminary estimation of the channel impulse response(CIR). Finally, fine estimations of both the sparsity and CIR are performed using residual differences derived from the coarsely estimated CIR. The adopted channel estimation scheme eliminates the need to insert training sequences into the data segment, thereby enhancing the data rate. The proposed channel estimation method enables effective channel estimation without requiring prior knowledge of channel sparsity.Simulation results show that the ASOMP algorithm achieves performance comparable to the OMP algorithm with known sparsity and outperforms the existing sparsity adaptive matching pursuit(SAMP) algorithm under low signal-to-noise ratio conditions. The data processing results from the 14th Chinese National Arctic Research Expedition's under-ice experiment validate the effectiveness and reliability of the proposed algorithm.
2025年02期 v.44 191-211页 [查看摘要][在线阅读][下载 1204K] [阅读次数：3 ] |[下载次数：0 ] |[引用频次：0 ] - WANG Yang;SHEN Tongsheng;WANG Tao;QIAO Gang;ZHOU Feng;LIU Feng;
Feature extraction of communication signal is easily affected by complex underwater acoustic interferences such as high noise and multipath effect,which lead to low classification rate.To solve this problem,a modulation classification method based on multi-feature combination for underwater acoustic communication signals is proposed.First,the multi-feature fusion method is designed to obtain signal features with stronger noise immunity,including wavelet time-frequency spectrum and two stronger spectral line features from square power spectrum and autocorrelation spectrum.Secondly,based on transfer learning theory,a lightweight network model is constructed to classify 2FSK and 4FSK signals using time-frequency features.Finally,combined with support vector machine optimized by particle swarm algorithm,an interclass recognition for non-frequency shift keying signals (including BPSK,QPSK,DSSS,OFDM signals) is designed using two stronger spectral line features.The results of simulation experiments demonstrate that the proposed method has good generalization abilities and noise immunity against underwater acoustic channels.The sea trial data verifies that the proposed method outperforms common neural network models in the classification rate.
2025年02期 v.44 212-230页 [查看摘要][在线阅读][下载 1556K] [阅读次数：3 ] |[下载次数：2 ] |[引用频次：0 ] - DU Shanwen;XIE Bosun;LIU Ding;
The present work proposes a method of approximate implementation of constant-power-equalization in signal mixing for horizontal Ambisonics with a nonuniform loudspeaker configuration derived from simulation and microphone-array recording.Ambisonics signal mixing with approximately constant-power-equalization is obtained by adding higher-order spatial harmonics in original signal mixing.The power characteristics of the mixed signal is further analyzed,and the appropriate truncation order is selected based on the criterion that the fluctuation of the overall signal power across the target source azimuth is less than 3.0 dB after equalization.Moore’s modified binaural loudness model serves to analyze the proposed method,and a psychoacoustic experiment is conducted to validate it.The results indicate that the proposed method reduces the timbre coloration in the azimuthal range where the power fluctuation is obvious without equalization.
2025年02期 v.44 231-256页 [查看摘要][在线阅读][下载 815K] [阅读次数：5 ] |[下载次数：4 ] |[引用频次：0 ] -
<正>1 Chinese Journal of Acoustics is the publication of the Acoustical Society of China and the Institute of Acoustics, Chinese Academy of Sciences, to promote the international understanding and collaboration in the field of acoustics. It publishes original works in all branches of acoustics in China. Contributions from invited guests and friends overseas are also solicited.
2025年02期 v.44 257页 [查看摘要][在线阅读][下载 65K] [阅读次数：3 ] |[下载次数：1 ] |[引用频次：0 ] 下载本期数据