scholarly journals Research on Local Sound Field Control Technology Based on Acoustic Metamaterial Triode Structure

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 204
Author(s):  
Peng Yang ◽  
Jingzhi Wu ◽  
Rongrong Zhao ◽  
Jianning Han
Keyword(s):  
Sound Wave ◽  
Sound Field ◽  
Acoustic Signals ◽  
Photoacoustic Detection ◽  
New Approach ◽  
Wave Signal ◽  
Specific Frequency ◽  
Local Sound ◽  
Energy Amplification ◽  
Working Efficiency

Cell photoacoustic detection faces the problem where the strength of the sound wave signal is so weak that it easily gets interfered by other acoustic signals. A sonic triode model based on an artificial periodic structure is designed by COMSOL Multiphysics 5.3a software (Stockholm, Sweden), and software simulations are conducted. Experiments show that when a sound wave with a specific frequency is input by the sound wave triode, it can produce an energy amplification effect on the sound wave signals of the same frequency and a blocking effect on the sound wave signals of other frequencies. This contrast effect is more obvious after increasing the sound pressure intensity of the input sound wave signal. It can effectively filter out interference sound signals. The study of the acoustic triode model provides a new approach for the acquisition and identification of acoustic signals in cell photoacoustic detection, which can significantly improve the working efficiency and accuracy of cell photoacoustic detection.

Interaction between Strong Sound Waves and Cloud Droplets: Theoretical Analysis

2021 ◽  
Author(s):  
Ying-Hui Jia ◽  
Fang-Fang Li ◽  
Kun Fang ◽  
Guang-Qian Wang ◽  
Jun Qiu
Keyword(s):  
Sound Wave ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Sound Field ◽  
Pressure Level ◽  
Velocity Variation ◽  
Time Range ◽  
Sound Waves ◽  
Cloud Droplets ◽  
Acoustic Frequency

AbstractRecently strong sound wave was proposed to enhance precipitation. The theoretical basis of this proposal has not been effectively studied either experimentally or theoretically. Based on the microscopic parameters of atmospheric cloud physics, this paper solved the complex nonlinear differential equation to show the movement characteristics of cloud droplets under the action of sound waves. The motion process of individual cloud droplet in a cloud layer in the acoustic field is discussed as well as the relative motion between two cloud droplets. The effects of different particle sizes and sound field characteristics on particle motion and collision are studied to analyze the dynamic effects of thunder-level sound waves on cloud droplets. The amplitude of velocity variation has positive correlation with Sound Pressure Level (SPL) and negative correlation with the frequency of the surrounding sound field. Under the action of low-frequency sound waves with sufficient intensity, individual cloud droplets could be forced to oscillate significantly. The droplet smaller than 40μm can be easily driven by sound waves of 50 Hz and 123.4 dB. The calculation of the collision process of two droplets reveals that the disorder of motion for polydisperse droplets is intensified, resulting in the broadening of the collision time range and spatial range. When the acoustic frequency is less than 100Hz (@ 123.4dB) or the Sound Pressure Level (SPL) is greater than 117.4dB (@ 50Hz), the sound wave can affect the collision of cloud droplets significantly. This study provides theoretical perspective of acoustic effect to the microphysics of atmospheric clouds.

scholarly journals Spiral Sound Wave Transducer Based on the Longitudinal Vibration

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3674 ◽  
Author(s):  
Wei Lu ◽  
Yu Lan ◽  
Rongzhen Guo ◽  
Qicheng Zhang ◽  
Shichang Li ◽  
...  
Keyword(s):  
Sound Wave ◽  
Longitudinal Vibration ◽  
Three Dimensional ◽  
Low Frequency ◽  
Sound Field ◽  
Field Measurements ◽  
Sound Waves ◽  
Underwater Sound ◽  
Three Dimensional Finite Element ◽  
Wave Transducer

A spiral sound wave transducer comprised of longitudinal vibrating elements has been proposed. This transducer was made from eight uniform radial distributed longitudinal vibrating elements, which could effectively generate low frequency underwater acoustic spiral waves. We discuss the production theory of spiral sound waves, which could be synthesized by two orthogonal acoustic dipoles with a phase difference of 90 degrees. The excitation voltage distribution of the transducer for emitting a spiral sound wave and the measurement method for the transducer is given. Three-dimensional finite element modeling (FEM)of the transducer was established for simulating the vibration modes and the acoustic characteristics of the transducers. Further, we fabricated a spiral sound wave transducer based on our design and simulations. It was found that the resonance frequency of the transducer was 10.8 kHz and that the transmitting voltage resonance was 140.5 dB. The underwater sound field measurements demonstrate that our designed transducer based on the longitudinal elements could successfully generate spiral sound waves.

Local sound field reproduction using digital signal processing

1996 ◽  
Vol 100 (3) ◽  
pp. 1584-1593 ◽  
Author(s):  
Ole Kirkeby ◽  
Philip A. Nelson ◽  
Felipe Orduna‐Bustamante ◽  
Hareo Hamada
Keyword(s):  
Signal Processing ◽  
Digital Signal Processing ◽  
Sound Field ◽  
Digital Signal ◽  
Local Sound

scholarly journals Fabrication of Si3N4-Based Artificial Basilar Membrane with ZnO Nanopillar Using MEMS Process

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Jun-Hyuk Kwak ◽  
Youngdo Jung ◽  
Kyungjun Song ◽  
Shin Hur
Keyword(s):  
Sound Wave ◽  
Basilar Membrane ◽  
Local Deformation ◽  
Electric Signal ◽  
Bottom Substrate ◽  
Specific Frequency ◽  
Acoustic Device ◽  
Artificial Basilar Membrane ◽  
Electric Signals ◽  
Mems Process

This paper presents the fabrication of Si3N4-based artificial basilar membrane (ABM) with ZnO nanopillar array. Structure of ABMs is composed of the logarithmically varying membrane fabricated by MEMS process and piezonanopillar array grown on the Si3N4-based membrane by hydrothermal method. We fabricate the bottom substrate containing Si3N4-based membrane for inducing the resonant motions from the sound wave and the top substrates of electrodes for acquiring electric signals. In addition, the bonding process of the top and bottom substrate is performed to build ABM device. Depending on sound wave input of the specific frequency, specific location of the ABM produces a resonant behavior. Then a local deformation of the piezonanopillar array produces an electric signal between top and bottom electrode. As experimental results of the fabricated ABM, the measured resonant frequencies are 2.34 kHz, 3.97 kHz, and 8.80 kHz and the produced electrical voltages on each resonant frequency are 794 nV, 398 nV, and 89 nV. Thus, this fabricated ABM device shows the possibility of being a biomimetic acoustic device.

scholarly journals Sound Scattering by a Flexible Plate Embedded on Free Surface

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Eldad J. Avital ◽  
Theodosios Korakianitis ◽  
Touvia Miloh
Keyword(s):  
Finite Difference ◽  
Sound Wave ◽  
Sound Field ◽  
Scattered Wave ◽  
External Pressure ◽  
Flexible Plate ◽  
Sound Scattering ◽  
Sound Structure ◽  
Structure Solution ◽  
Finite Difference Solution

Sound wave scattering by a flexible plate embedded on water surface is considered. Linear acoustics and plate elasticity are assumed. The aim is to assess the effect of the plate’s flexibility on sound scattering and the potential in using that flexibility for this purpose. A combined sound-structure solution is used, which is based on a Fourier transform of the sound field and a finite-difference numerical-solution of the plate’s dynamics. The solution is implemented for a circular plate subject to a perpendicular incoming monochromatic sound wave. A very good agreement is achieved with a finite-difference solution of the sound field. It is shown that the flexibility of the plate dampens its scattered sound wave regardless of the type of the plate’s edge support. A hole in the plate is shown to further scatter the sound wave to form maxima in the near sound field. It is suggested that applying an external oscillatory pressure on the plate can reduce significantly and even eliminate its scattered wave, thus making the plate close to acoustically invisible. A uniformly distributed external pressure is found capable of achieving that aim as long as the plate is free edged or is not highly acoustically noncompact.

scholarly journals On the determination of the sound wave parameters during cavitation destruction of loam soil

2021 ◽  
Vol 273 ◽  
pp. 05012
Author(s):  
Sergey Starovoytov ◽  
Valery Korotchenya
Keyword(s):  
Surface Tension ◽  
Compressive Strength ◽  
Soil Solution ◽  
Sound Wave ◽  
Sound Pressure ◽  
Sound Field ◽  
Propagation Speed ◽  
Ultimate Compressive Strength ◽  
Loam Soil ◽  
Tillage Depth

Finding the values of the frequency and sound pressure of an acoustic wave, which ensures the process of loosening loam soil, is a very important task. We assumed that the value of the average sound pressure at which the intensity of the cavitation process would be maximum is equal to twice the value of the hydrostatic pressure. The minimum radius of the formed bubble is directly proportional to the doubled surface tension of the soil solution and inversely proportional to the ultimate compressive strength of soil. The value of the ultimate compressive strength of loam soil depends on its absolute moisture content. The angular frequency of the sound field is directly proportional to the tillage depth and the ultimate compressive strength of the soil, and inversely proportional to the sound wave propagation speed and the surface tension of the soil solution. With a loam soil density ρ=1554 kg/m3 and a tillage depth h=0.3 m, the average sound pressure was PA=9324 Pa. In the interval of physical ripeness of loam soil, the oscillation frequency of the sound field was in the range of 19 762 to 37 773 s-1.

Mechanism of Cloud Droplet Motion under Sound Wave Actions

2020 ◽  
Vol 37 (9) ◽  
pp. 1539-1550 ◽  
Author(s):  
Fang-Fang Li ◽  
Ying-Hui Jia ◽  
Guang-Qian Wang ◽  
Jun Qiu
Keyword(s):  
Droplet Size ◽  
Sound Wave ◽  
Dominant Role ◽  
Sound Field ◽  
Cloud Droplet ◽  
Sound Frequency ◽  
Sound Waves ◽  
Cloud Droplets ◽  
Maximum Displacement ◽  
Precipitation Enhancement

AbstractSound waves have proven to be effective in promoting the interaction and aggregation of droplets. It is necessary to theoretically study the motion of particles in a sound field to develop new acoustic technology for precipitation enhancement. In this paper, the motion of cloud droplets due to a traveling sound wave field emitted from the ground to the air is simulated using the motion equation of point particles. The force condition of the particles in the oscillating flow field is analyzed. Meanwhile, the effects of droplet size, sound frequency, and sound pressure level (SPL) on the velocity and displacement of the droplets are also investigated. The results show that Stokes force and gravity play a dominant role in the falling process of cloud droplets, and the effect of the sound wave is mainly reflected in the fluctuation of velocity and displacement, which also promotes the displacement of cloud droplets to a certain extent. The maximum displacement increments of cloud droplets of 10 µm can reach 9200 µm due to the action of sound waves of 50 Hz and 143.4 dB. The SPL required for a noticeable velocity fluctuation for droplets of 10 µm with frequency of 50 Hz is 88.2 dB. When SPL < 100 dB and frequency > 500 Hz, the effect is negligible. The cloud droplet size plays a significant role in the motion, and the sound action is weaker for larger particles. For a smaller sound frequency and higher SPL, the effect of the sound wave is more prominent.

The Vibrations of a Thin-Walled Stiffened Cylinder in an Acoustic Field

1959 ◽  
Vol 10 (1) ◽  
pp. 47-64 ◽  
Author(s):  
J. H. Foxwell ◽  
R. E. Franklin
Keyword(s):  
Acoustic Wave ◽  
Acoustic Field ◽  
Sound Wave ◽  
Sound Field ◽  
Practical Experience ◽  
Volume Of Fluid ◽  
Response Characteristics ◽  
Thin Walled

SummaryWhen a vibrating structure encloses a volume of fluid, the acoustic effects within this volume modify considerably the response characteristics of the structure, provided that the cylinder is vibrating in radial modes only. Measurements made of the displacement caused by a particular sound wave are of the same order as the values predicted. The calculation of the response of the cylinder to an acoustic wave also yields the sound field inside the cylinder and, again, the results are in general agreement with practical experience.

scholarly journals An Acoustic Tomography Technique for Concurrently Observing the Structure of the Atmosphere and Water Bodies

2017 ◽  
Vol 34 (3) ◽  
pp. 617-629 ◽  
Author(s):  
Anthony Finn ◽  
Kevin Rogers
Keyword(s):  
Theoretical Analysis ◽  
Sound Speed ◽  
Water Surface ◽  
Low Frequency ◽  
Sound Field ◽  
Acoustic Signals ◽  
Acoustic Tomography ◽  
Radio Waves ◽  
Surface Errors ◽  
Underwater Sensors

AbstractThe opacity of water to radio waves means there are few, if any, techniques for remotely sensing it and the atmosphere concurrently. However, both these media are transparent to low-frequency sound (<300 Hz), which makes it possible to contemplate systems that take advantage of the natural integration along acoustic paths of signals propagating through both media. This paper proposes—and examines with theoretical analysis—a method that exploits the harmonics generated by the natural signature of a propeller-driven aircraft as it overflies an array of surface and underwater sensors. Correspondence of the projected and observed narrowband acoustic signals, which are monitored synchronously on board the aircraft and by both sensor sets, allows the exact travel time of detected rays to be related to a linear model of the constituent terms of sound speed. These observations may then be inverted using tomography to determine the inhomogeneous structures of both regions. As the signature of the aircraft comprises a series of harmonics between 50 Hz and 1 kHz, the horizontal detection limits of such a system may be up to a few hundred meters, depending on the depth of the sensors, roughness of the water surface, errors due to refraction, and magnitude of the sound field generated by the source aircraft. The approach would permit temperature, wind, and current velocity profiles to be observed both above and below the water’s surface.

scholarly journals A New Approach to Analysis of the Properties of Disordered Structures in Hydrodynamic Acoustics as Supplement to Technology and Detection Theory

2021 ◽  
pp. 306-315
Author(s):  
Pavel A. Starodubtsev ◽  
Evgeny P. Starodubtsev ◽  
Roman N. Alifanov ◽  
Grigory V. Dorofeev
Keyword(s):  
Sound Field ◽  
Principle Of Superposition ◽  
New Approach ◽  
Disordered Structures ◽  
Complex Interactions ◽  
Rotation Of The Earth ◽  
The Fourier Transform ◽  
Fundamental Equations ◽  
Physical Phenomena ◽  
Special Case

The article presents the results of the analysis of the properties of disordered structures in hydrodynamic acoustics, associated with the process of detecting physical phenomena and marine objects based on the results of their mechanical impact on the marine environment, in which acoustic vibrations propagate. If vortices, attractors, fractals arise as a result of complex interactions of forces of nature (upwellings, seiches, Coriolis forces, currents, convection flows, rotation of the Earth) and are essentially mechanical effects on the environment of formation and propagation of an acoustic field, then mechanical sources of sound introduced into the hydrosphere (water) should repeat fractal iterations on a smaller scale at the sound field level. Recognizing the equations of hydrodynamics (the equation of motion, the equation of continuity, and the equation of state) as the fundamental equations of hydroacoustics, the nonlinearity of these equations is proposed to be considered the theory of the hydroacoustic field as nonlinear, and the linearity of the processes in this study is considered a special case. The principle of superposition also becomes a special case, and the Fourier transform, remaining necessary, loses its sufficiency. Fractal analysis in combination with wavelet analysis should be involved to help him

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