Acoustic Method Research Articles

An acoustic impedance design method for tubular structures with broadband sound insulations and efficient air ventilation

In this research, we proposed an acoustic impedance-based design method to increase the soundproofing bandwidths and maintain efficient air ventilation for tubular structures consisting of hollow air-flowing channels. This research has great potential to provide design guidelines based on an acoustic impedance model and even/odd mode analysis for hollow-tube ventilated devices containing resonance and antiresonances. We introduced a thin ventilated structure with a subwavelength thickness of 0.107 λ where λ corresponds to the lowest frequency within the filtering bandwidth, a 19.4 % cross-section open for air passage, and a 10 dB fractional bandwidth of 110.2 % (i.e., 90 % sound energy is blocked), which is broader than that of a conventional Fano-like structure of 44.7 %. To experimentally verify the proposed approach, two prototypes, including lateral-coupled and longitudinal-coupled devices, were designed, fabricated with 3D printing, and experimentally characterized via a commercial-available impedance tube system. The simulations matched the measurements and demonstrated the 10 dB fractional bandwidth of 65 % and 91.5 % and ventilation efficiencies of 21.4 % and 33.4 %, respectively. The main contribution of this work is that the proposed approach can be adopted for lateral or longitudinal coupled ventilated structures with broadband sound insulations and lower the effects of resonance-induced sound transmissions. Besides, the proposed acoustic-impedance model can significantly save the required tremendous computational resources and time compared to FEM simulations. Moreover, the proposed lateral and longitudinal ventilated structures are expected to benefit broadband sound filtering and noise reduction for thin panel or tubular silencers

Petroleum System Analysis and Burial History of Middle Permian Source Rock in Turpan–Hami Basin, NW China

The pre-Jurassic in the north depression of the Tuha depression is the most favorable replacement strata to obtain new reserves in the Turpan–Hami Basin. (Pre-Jurassic, in this paper, refers to the Permian and Triassic.) The main source rocks are the Taodonggou Group, of which the burial history and hydrocarbon generation potential remain unconfirmed. The investigation of the burial and thermal history is vital for the basin analysis and hydrocarbon exploration. Therefore, in this paper, by using the acoustic time difference method, vitrinite reflectance method, stratigraphic trend method and PetroMod-1D software, the differential characteristics of denudation thickness, burial history and thermal evolution history of different tectonic units in different periods of Taibei Sag in the Turpan–Hami basin are studied, and their influence on the petroleum system is analyzed, and then the zones with exploration potential are optimized. The results show that the Taibei Sag has experienced multiple tectonic uplift events. The Late Indosinian movement has profound effects on the Taodonggou Group source rocks. The rather large uplift amplitude postpones the maturation of source rocks. In addition, the Turpan–Hami Basin is a typical cold basin. Therefore, the thermal maturity of the source rocks is relatively low, with respect to the relatively deep burial. The thermal histories of the different sub-sags in the study area are slightly differentiated from each other. The Taodonggou Group source rocks in the Taibei Sag generally became mature during the Mid–Late Jurassic epoch, except for those in the Central–Southern Shanbei sub-sag, represented by Well LT-1, which reached the mature stage during the Late Triassic epoch. The study area has well-developed reservoir rocks, and effective reservoir bodies are formed in the slope zone and near the Tainan Sag, due to the higher porosity and permeability of reservoir rocks. The statistics related to the faults and an analysis of the structural styles of oil reservoirs indicate that the structural slope and anticline of the Huobei, Lianbei and Shanbei sub-sags are favorable for increasing reserves and production of hydrocarbons.

Cyclic dynamic-static loading and acoustic emission signal monitoring method of coal in solid–gas coupling environment and its application

Cyclic dynamic-static loading and acoustic emission signal monitoring method of coal in solid–gas coupling environment and its application

A review of the Research on Tunnel Lining Voiding Detection Based on Acoustic Vibration Method

In the study of nondestructive testing technology for tunnel lining voiding detection, the traditional nondestructive testing technology has many drawbacks such as poor detection accuracy, high subjectivity, and easy to be interfered with, etc., and the combination of acoustic vibration method and deep learning technology has the problems of uneven distribution of the data set, poor interpretability, and other problems that are difficult to be applied to industrial applications, which summarizes the current acoustic vibration testing technology and its application to the study of tunnel lining voiding. Firstly, the non-destructive testing techniques used in the current tunnel lining voiding detection research are sorted out, and then a variety of tunnel lining voiding detection research methods based on acoustic vibration method with potential applications in the industrial field are analyzed, followed by an overview of the current situation from the point of view of deep learning combined with the acoustic vibration method for the detection of tunnel lining voiding, and then the direction of the next step of the research is discussed and analyzed. The full paper is summarized, and future challenges are pointed out.

High-efficiency prediction method for helicopter global/ground noise based on near-field acoustic holography

Noise reduction program design is an effective approach that relies on efficient noise prediction for reducing ground noise during flight. The existing noise prediction methods have the limitations of being computationally expensive or only applicable to far-fields. In this paper, a High-Efficiency Prediction Method (HEPM) for helicopter global/ground noise based on near-field acoustic holography is proposed. The HEPM can predict the global noise based on acoustic modal analysis and has the advantages of high prediction accuracy and low time cost. The process is given as follows: firstly, the rotor noise on the holographic surface in the specified flight is obtained by simulations or experiments. Secondly, the global noise model, which maps time-domain noise to acoustic modes, is established based on near-field acoustic holography and Fourier acoustic analysis methods. Finally, combined with acoustic modal amplitude, the model established enables efficiently predicting the global/ground noise in the corresponding flight state. To verify the accuracy of the prediction method, a simulation study is conducted in hovering and forward flight states using a model helicopter with a 2-meter rotor and Rotor Body Interaction (ROBIN) fuselage. The comparison of HEPM with numerical results shows that the average prediction errors of the global and ground noise are less than 0.3 dB and 0.2 dB, respectively. For a region containing 100000 observers, the computation time of the HEPM is only one-fifth of that of the acoustic hemisphere method, demonstrating the rapidity of the proposed method.

Recent advances on the fabrication and application of sound absorption coating-based textile composites

Noise pollution has been considered as a serious threat to the health of humans. The application of sound absorption materials is an effective noise reduction approach. Fibrous materials exhibit the unique micro-structures including small diameter, large specific surface area, and high porosity, which has been widely developed for sound absorption. Recently, rapid growth has been observed in the coating treatment of fibrous based materials and composites for acoustic applications, which can be attributed to the advantages of a facile production process, cost-effectiveness, and good sound absorption capability. This review aims to provide a brief overview on different coating layers of fibrous materials for improved sound absorption properties. The details of various factors affecting the acoustic behavior of coating materials are described. Among them, polymer coating is a widely used acoustic treatment method, adding particles and nanofiber materials to the polymer matrix, and carrying out structural design, which can further improve the sound absorption performance of textile materials. According to the different needs of the application field, different coating treatment methods have their own advantages. In summary, coating materials are promising to be used in buildings and interiors for efficient noise reduction and control.

Leakage detection method of underground heating pipeline based on improved wavelet threshold function

For urban heating pipeline network, the intelligent and precise detection is an important guarantee for urban heating infrastructure of the safe and low-carbon operation. Heating pipe network was directly buried in the soil and difficult to detect the leakage point due to lack of non-excavation detection method for rapid repair. An improved noise reduction algorithm of the wavelet threshold function coupled with the acoustic method was used for the directly buried pipe leakage detection. Large-scale leakage experimental tests were used to validate the reliability. The influences of temperature, pressure, flowrates and leakage distance on the frequency and time domains were then investigated. Results show that the improved threshold function could well detect the leakage for directly buried hot water heating pipes. When the temperature increases, the leakage frequency domain spreads from 200 - 800 Hz to 50–1500 Hz. The pressure, flow rate, and leak point location could affect the amplitude feature. The accuracy ranges of the improved method in the different location, temperature and pressure and flowrates are separately 0.11–2.36%, 0.11–1.96%,0.11–3.49% and 0.16–1.55%, respectively.

Research on the effects of resonance tube bending in loop thermoacoustic refrigeration system

A high-power-density heat-driven loop thermoacoustic refrigeration system has the potential to meet miniaturization requirements of vehicle waste heat recovery systems. Given the strict space constraints in vehicle power compartments and the need to reduce equipment footprint, the resonance tubes need to be bent and coiled. However, the introduction of curvature may increase losses in resonance tubes. In order to evaluate the minor losses caused by bending on resonance tubes, a double-acoustic-source driven acoustic field modulation platform was constructed to experimentally investigate bent resonance tubes with different arc lengths under two common bending angles (90° and 180°) under high working pressure. Through the acoustic field reconstruction method, the acoustic field distributions of each resonance tube were obtained, and the effects of changes in bending angle and arc length on acoustic field and acoustic power dissipation were analyzed. The results indicated that the introduction of curvature leads to an increase in traveling-standing wave ratio, acoustic power, and acoustic power dissipation, with the degree of increase influenced by both curvature and arc length. Under the same bending angle, the minor loss is directly proportional to curvature, and there is an ExpAssoc function relationship between minor loss coefficient and curvature. Under the same curvature, the minor loss is not proportional to arc length, and minor loss coefficient slightly increases with the arc length doubles. The findings fill the research gap in resonance tube bending in loop thermoacoustic systems and provide guidance for the selection of resonance tube bending parameters.

An Underwater Acoustic Target Recognition Method Based on Transfer Learning

An Underwater Acoustic Target Recognition Method Based on Transfer Learning

Evaluation of a Local Acoustic Resonance Method for Coating Thickness Determination on Stochastic Metal Hybrid Foams

Novel cellular materials promise a combination of high strength and low specific weight for sustainable and energy‐efficient material design. Inhomogeneities of the materials, such as varying coating thickness, are inherent to the production process but require advanced characterization in order to better understand mechanical properties. Herein, global and local acoustic analysis for nondestructive characterization of local coating thickness on an open‐porous hybrid metal foam system is studied. Experiments and numerical simulations are carried out to evaluate vibration behavior stimulated by a low‐energy impact. The novelty of the work is the use of local excitation and analysis of decay times to determine coating thickness gradients. This qualitative measurement can inform and speed up the material development process due to its simplicity, speed, and low cost. Furthermore, it provides a basis for quality control when scaling up the technology of metal hybrid foams for industrial applications.

A convenient acoustic measurement of femtosecond filamentation based on a cell phone

The acoustic diagnostic method has been widely used in diagnosing femtosecond filamentation. In this work, acoustic measurements of femtosecond laser filamentation and weakly air-ionized region are conducted using a readily available portable device - a cell phone. The signal is extracted by employing digital signal processing method of Fourier transformation filtering. The results demonstrate that the method can be used for effective measurements even in noisy environments. This greatly enhances the accuracy and portability of the acoustic method, providing a practical approach for improving acoustic diagnostics.

Advanced acoustic leak detection in water distribution networks using integrated generative model

Water distribution networks (WDNs) experience significant water loss due to leaks, necessitating advanced water leak detection methods. However, machine learning-based acoustic method heavily relies on signal information and is limited by data scarcity and the limited diversity of available data. To address this challenge and enhance water leak detection in WDNs, this study proposes an LSTM-GAN approach. Acoustic signals are collected from WDNs to train the LSTM-GAN model, which generates synthetic leak signals to enhance the dataset. The validity of the generative method is evaluated through t-SNE and acoustic characteristics analysis. LSTM-based water leak detection models are established and compared using the original and the generated datasets to confirm the efficacy of generated samples in improving water leak detection performances. The capability of LSTM-GAN has been evaluated through different perspectives, including sensitivity analysis and model comparison. The results validate the quality and consistency of the generated acoustic signals under leak conditions. Besides, the optimal number of generated samples should be determined according to the requirements and characteristics of the leak detection task. Furthermore, the comparison between the proposed method and other acoustic generative methods demonstrates the superiority of LSTM-GAN-generated signals in enhancing the performance of leak detection models. The proposed generative method offers an innovative approach to facilitate machine learning-based leak detection models with limited data, thereby enhancing robustness.

Multiple methods for acoustic emission source location in metal waveguides

Research on sound source location, which is widely used in engineering, is an important topic in acoustic emission (AE) technology. Traditional double-ended location methods have certain limitations, such as sound sources being located between two sensors, a single application scenario and possible time delays. In this study, three theoretically feasible location methods were proposed and experimentally verified based on AE propagation theory to test the accuracy of the AE source location and explore single/double-sensor line location in metal waveguides. The experiments measured the propagation speed of longitudinal and transverse waves in the waveguide and verified the feasibilities of the three acoustic source location methods based on waveform analysis, with waveform matching using the wave range and wave speed differences. The experimental results show a location error of less than 3% for the double-ended and double wave-speed methods and less than 6% for the double-waveguide and reflective-surface types.

Optoacoustic interferometric characterization system (OPTICS) for the evaluation of fuel quality through speed of sound measurements

Ultrasonic techniques have been applied to assess crucial physical parameters in various types of fuels including the speed of sound (SoS), the bulk modulus and the acoustic attenuation coefficient. Such investigations may have important practical significance as the knowledge of fuel properties is directly related to the analysis of combustion characteristics, engine’s overall performance and exhaust emission in the environment. Nevertheless, typical pulse-echo acoustic methods, require the exact determination of both acoustic source – reflector distance and the time of flight of a finite temporal width ultrasonic pulse, setting thus an upper limit as regards the accuracy of the measurements. To encounter these challenges, we present a novel technology implemented through a low-cost and potentially portable optoacoustic interferometric characterization system (OPTICS) for the investigation of SoS variations in common fuels including automotive diesel, hydrous ethanol and gasoline. At 25 °C, diesel/kerosene blends demonstrated a SoS variation ranging from 1322.91 m/s (0.6 diesel volume fraction) to 1349.79 m/s (diesel fuel only), whereas hydrous ethanol samples varied between 1199.92 m/s (0.95 ethanol volume fraction) to 1149.39 m/s (pure ethanol only). Finally, assessments for 95 and 100 research octane number (RON) gasoline blends showed a SoS range from 1134.42 m/s (RON 95) to 1159.86 m/s (RON 100). The high precision and repeatability (relative uncertainty: ∼10-4) of the performed SoS measurements in controlled samples, has demonstrated the promising potential of OPTICS for the evaluation of fuel physical properties as well as the potential detection of contamination with adulterants.

Measurement the 3D temperature distribution in the combustion zone using acoustic tomography and nolinear wavefont tracing

A non-invasive temperature measurement method in three dimensions is proposed to reconstruct the three-dimensional temperature. It relies on the use of nonlinear acoustic travel-time tomography, which incorporates acoustic path tracing, Gaussian kernel function, and modified Tikhonov regularization. Sound signals can be distorted due to large average temperature gradients and oscillatory release of heat in the combustion region. The effective acoustic signal is extracted based on spectral subtraction to evaluate the sound propagation time under distorted signals. The analysis of experimental errors indicates that the proposed acoustic pyrometry method has an average relative error of less than 15% compared to the time-averaged temperature measured by thermocouples. This result verifies the efficacy of the method when it comes to accurately reconstructing the temperature field in the combustion area. The reduction in error is attributed to the consideration of acoustic ray tracing within the proposed method.

Active Flux Methods for Hyperbolic Systems Using the Method of Bicharacteristics

The Active Flux method is a third order accurate finite volume method for hyperbolic conservation laws, which is based on the use of point values as well as cell average values of the conserved quantities. The resulting method is fully discrete and has a compact stencil in space and time. An important component of Active Flux methods is the evolution formula for the update of the point values. A previously proposed exact evolution formula for acoustics is reviewed and used to construct an Active Flux method for the two-dimensional Maxwell’s equation. Furthermore, the method of bicharacteristics is discussed as a methodology for the derivation of truly multidimensional approximative evolution operators that can be used for the evolution of point values in Active Flux methods. We study accuracy and stability of the resulting methods for acoustics and compare with the Active Flux method that uses the exact evolution operator. Finally, we used the method of bicharacteristics to derive Cartesian grid Active Flux methods for the linearised and nonlinear Euler equations. Numerous test computations illustrate the performance of these new Active Flux methods.

Leak detection systems in oil and gas fields

The article is devoted to a review of methodological approaches to the localization and detection of liquid and gas leaks when using pipelines in oil and gas fields. The relevance of the issue is explained by the fact that a significant number of incidents that negatively affect the activities of oil and gas companies occur in connection with the leakage of resources in oil and gas fields. The purpose of the study is to present the state of the art of modern acoustic and infrared methods used to detect liquid and gas leaks in oil and gas fields. The author used various classifications to analyze the characteristics of the methods, allowing them to be divided into active and passive; acoustic, optical, electrical, and chemical systems methods; permanently installed and mobile liquid and gas leak detection systems. Among the considered methods for detecting liquid and gas leaks in oil and gas fields, acoustic and infrared methods are the most effective; they can be quite easily integrated into an existing liquid and gas leak detection system. Infrared and acoustic methods can also be used on pipelines, with the latter being used more often than infrared methods due to the fact that they cover very long pipelines using pinpoint liquid and gas leak detectors in oil and gas fields. More advanced concepts for leak detection systems in oil and gas fields involve a combination of several methods, for example, the study reflected the specificity of combining a magnetic and ultrasonic sensor for detecting liquid and gas leaks in oil and gas fields. Although innovative concepts continue to be developed, some oil and gas enterprises still employ methods based on manual human labor which includes examining and sampling the contents of pipelines. In conclusion, it was noted that at the present stage the practical application of several methods simultaneously in the system for detecting liquid and gas leaks in oil and gas fields is required, since each of them individually has significant disadvantages for oil and gas enterprises, which can be offset by an appropriate combination of existing methods.

Unidentified fish sounds as indicators of coral reef health and comparison to other acoustic methods

The global decline of coral reefs is a major contributor to the global biodiversity crisis and requires improved monitoring at these critically important habitats. Non-invasive passive acoustic assessments may address this need, leveraging the rich variety and spatiotemporal variability of biological sounds present in coral reef environments and offering near-continuous temporal coverage. Despite this, acoustic metrics that reliably represent coral reef health are still debated, and ground-truthing of methods is limited. Here we investigated how the prevalence of low frequency biotic sounds (without species information) relates to coral reef health, providing a foundation from which one can compare assessment methods. We first quantified call rates of these low frequency sounds for three reefs exhibiting different community assemblages around St. John, U.S. Virgin Islands, by manually annotating presumed fish noises for 1 min every 30 min across 8 days for each site. Annotated days were selected at key points across lunar cycles. These call rates were then compared with traditional visual surveys, and several acoustic methods and indices commonly used in underwater soundscape research. We found that, overall, manually detected fish call rates successfully differentiated between the three reefs, capturing variation in crepuscular activity levels–a pattern consistent with previous work that highlights the importance of diel choruses. Moreover, fish vocal rates were predictors of hard coral cover, fish abundance, and fish species richness, while most acoustic indices failed to parse out fine distinctions among the three sites. Some, such as the Acoustic Complexity Index, failed to reveal any expected differences between sites or times of day, while the Bioacoustic Index could only identify the most acoustically active reef, otherwise having weak correlations to visual metrics. Of the indices tested, root-mean-squared sound pressure level and Acoustic Entropy, both calculated in the low frequency fish band (50–1,200 Hz), showed the strongest association with visual health measures. These findings present an important step toward using soundscape cues for reef health assessments. The limited generalizability of acoustic indices across different locations emphasizes the need for caution in their application. Therefore, it is crucial to improve methods utilizing fish sounds, such as automatic fish call detectors that are able to generalize well to new soundscapes.

Introduction to the Acoustical Oceanography Technical Committee

The Acoustical Oceanography Technical Committee is responsible for representing and fostering Acoustical Oceanography within the Acoustical Society of America. It is concerned with the development and use of acoustical techniques to measure and understand the physical, biological, geological, and chemical parameters and processes of the sea. Several acoustical methods are used to quantitatively study various oceanographic processes. Approaches include ocean parameter estimation by acoustical methods, remote sensing by passive and active acoustics, acoustic imaging, inversion, and tomography, and developing acoustical instrumentation for oceanographic studies.

Acoustic monitoring of harbor porpoises in Hood Canal, WA: Efforts to improve detection of a highly cryptic cetacean

Harbor porpoises (Phocoena phocoena) are the smallest, most abundant cetaceans occurring within the waters of the US Navy’s Northwest Training and Testing Ranges. The ability to detect harbor porpoise and monitor their presence over time is essential to assessing potential impacts of Navy activities. This can be difficult due to their highly cryptic nature exhibited in their surface behavior (vessel avoidance) and acoustic repertoire (producing only high-frequency clicks). This presents significant challenges for both visual and acoustic (PAM) survey methods. Here, we discuss the Navy’s efforts to improve harbor porpoise monitoring capability using an automated acoustic detection system. We tested multiple detection algorithms and evaluated their performance in identifying and extracting harbor porpoise clicks from acoustic recordings collected in Hood Canal, WA. Using this detection data combined with data collected from concurrent visual surveys of Hood Canal, we explored how acoustic and visual methods may be used in concert to improve harbor porpoise monitoring. Hood Canal provides a unique opportunity to do this, as it is the only known US Navy range with a resident population of harbor porpoise. These efforts will also inform future behavioral response studies needed to measure the impact of Navy sounds to individual animals.