An improvement of the generalized discrete Fourier series based patch near-field acoustical holography

Zhang, Man-Ying; Hu, Dingyu; Yang, Chao; Shi, Wei; Liao, Aihua

doi:10.1016/j.apacoust.2020.107711

Cited by 11 publications

(5 citation statements)

References 18 publications

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“…1) Dirichlet condition: 𝑓(𝑥) is segmentally monotone on an interval near 𝑥 0 and the number of discontinuity points on the interval is at most a finite number [21].…”

Section: Generalized Fourier Series Algorithmmentioning

confidence: 99%

Application of biofilm-membrane bioreactor in municipal wastewater treatment

Li,

Qian,

Shi

et al. 2023

Applied Mathematics and Nonlinear Sciences

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To verify the feasibility of biofilm-membrane bioreactor in municipal wastewater treatment. In this paper, based on the Fourier series algorithm, the basic configuration of biofilm-membrane bioreactor, the design of membrane bioreactor test index and method, the proposed urban wastewater treatment system based on biofilm-membrane bioreactor, and the creation of experiments to verify the biofilm-membrane bioreactor with the example of urban wastewater in the sewer of residential buildings in the district on the two CODCr and NH4 +-N in urban wastewater in municipal wastewater. The results showed that the removal rate of CODCr in municipal wastewater by the biofilm-membrane bioreactor system increased with time, and the removal rate was stable at about 83%. The NH4 +-N removal rate increased with time and was stable between 85 and 90%. It can be shown that biofilm-membrane bioreactor can sufficiently reduce the concentration of CODCr and NH4 +-N in municipal wastewater, thus promoting municipal wastewater treatment. It also presents a new solution for urban wastewater treatment.

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“…1) Dirichlet condition: 𝑓(𝑥) is segmentally monotone on an interval near 𝑥 0 and the number of discontinuity points on the interval is at most a finite number [21].…”

Section: Generalized Fourier Series Algorithmmentioning

confidence: 99%

Application of biofilm-membrane bioreactor in municipal wastewater treatment

Li,

Qian,

Shi

et al. 2023

Applied Mathematics and Nonlinear Sciences

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show abstract

“…Near-field acoustical holography (NAH) [1][2][3][4][5] has been proven to be a powerful tool for reconstructing the three-dimensional sound field generated by a vibrating structure, using sound pressures measured by a sensor array in the near-field of the structure surface. Implementations of NAH generally require that the sensor array be placed in a source-free region, because they utilize the free-space Green's functions to relate the radiated sound pressures at different field points.…”

Section: Introductionmentioning

confidence: 99%

Experimental Validation of Reconstruction of Sound Source Radiation in an Underwater Half-Space Bounded by a Water-Air Interface

Chen,

Zhou,

Lou

et al. 2024

The International Journal of Acoustics and Vibration

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When a vibrating structure is located in a half-space bounded by a reflecting surface, the measured sound pressures are polluted by the reflection, so that they cannot show the actual sound radiation from the structure. The half-space spherical wave function expansion-based near-field acoustical holography approach is proposed to reconstruct the direct radiation from the sound source using the polluted sound pressures, which has been validated by numerical simulations. This paper deals with the experimental validation of this approach applied in an underwater half-space bounded by a water-air interface. The sound pressures measured in the half-space are used as the input data. The reconstructed sound pressures obtained are compared with benchmarks measured in a free space. The results indicate that the influences of the water-air interface reflection on the measured sound pressures can be greatly reduced in the entire frequency range investigated. The normalized relative reconstruction error introduced by the parameters of the hydrophone array and the water tank in the experiment is analyzed. The results of the experimental validation show that the proposed approach is promising for accurately measuring sound signals radiated from manned or unmanned vehicles or equipment underwater near a water-air interface.

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“…Hu [23] constructed a sparse basis by ESM and the singular value decomposition (SVD). Additionally, plane wave functions [24], cylindrical wave functions and spherical wave functions [25,26] can also be selected as the sparse spatial basis. As for the sparse regularization, various algorithms have been applied to NAH successfully, such as direct l 1 -norm sparse regularization [27], WBH [20], iterative sparse methods [28], Bayesian compressive sensing [29,30], alternating direction method of multipliers [31], block sparse Bayesian learning [32,33] and so on.…”

Section: Introductionmentioning

confidence: 99%

Sound Field Reconstruction Using Prolate Spheroidal Wave Functions and Sparse Regularization

Zhang,

Lou,

Zhu

et al. 2023

Sensors

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Near-field acoustic holography (NAH) based on compressing sensing (CS) theory enables accurate reconstruction of sound fields using a limited number of sampling points. However, the successful implementation of this technique depends on two crucial factors: (1) the appropriate selection or construction of the spatial basis and (2) an effective sparse regularization process. To enhance reconstruction performance for elongated sound sources, this paper proposes a novel sound field reconstruction method that combines prolate spheroidal wave functions (PSWFs) with the orthogonal matching pursuit (OMP) algorithm. In this method, PSWFs serve as a sparse spatial basis for representing the radiated sound field. The sparse coefficients are determined by the OMP algorithm in a linear subspace composed of basic functions that best match the residual error. The OMP algorithm effectively identifies significant components before potentially selecting incorrect ones by setting an appropriate stopping rule. Numerical simulations are conducted using a line-array source model. The results show that the proposed method can accurately reconstruct the sound pressures of the elongated source model using a relatively small number of samplings. In addition, the proposed method exhibits robustness across a wide frequency range, diverse array configurations and various sampling numbers. The experimental results further validate the feasibility and reliability of the proposed method.

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An improvement of the generalized discrete Fourier series based patch near-field acoustical holography

Cited by 11 publications

References 18 publications

Application of biofilm-membrane bioreactor in municipal wastewater treatment

Application of biofilm-membrane bioreactor in municipal wastewater treatment

Experimental Validation of Reconstruction of Sound Source Radiation in an Underwater Half-Space Bounded by a Water-Air Interface

Sound Field Reconstruction Using Prolate Spheroidal Wave Functions and Sparse Regularization

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