On the Determination of the Acoustic Power of a Source of Sound in Semi‐Reverberant Spaces

Noise Control ◽  
1961 ◽  
Vol 7 (1) ◽  
pp. 21-29 ◽  
Author(s):  
R. J. Wells ◽  
Francis M. Wiener
Keyword(s):  
Acoustic Power

scholarly journals Nanogenerator for determination of acoustic power in ultrasonic reactors

2021 ◽  
pp. 105718
Author(s):  
Krystian Mistewicz ◽  
Marcin Jesionek ◽  
Hoe Joon Kim ◽  
Sugato Hajra ◽  
Mateusz Kozioł ◽  
...  
Keyword(s):  
Acoustic Power ◽  
Ultrasonic Reactors

Method of determination of acoustic power

2008 ◽  
Vol 40 (6) ◽  
pp. 537-539
Author(s):  
E. V. Rusina
Keyword(s):  
Acoustic Power ◽  
Method Of Determination

A Whistling Criterion for Two Orifices in Series

2009 ◽  
Author(s):  
Romain Lacombe ◽  
Yves Aure´gan ◽  
Pierre Moussou
Keyword(s):  
Pressure Drop ◽  
Power Plants ◽  
Acoustic Power ◽  
Scattering Matrix ◽  
In Series ◽  
Inner Diameter ◽  
Acoustic Amplifier ◽  
Experimental Criterion

Whistling phenomena in pipe power plants have been observed in the past years. It occurs at pressure drop devices where vortex shedding is established. It generates high noise levels and excessive vibrations. Aure´gan and Starobinsky [1] have developed an experimental criterion to predict whistling frequencies of pressure drop devices submitted to plane propagating pressure waves. This criterion estimates the net acoustic power, an acoustic exergy generation indicating that the device behaves as an acoustic amplifier. The corresponding frequencies are potential whistling frequencies. The application of the criterion only requires the determination of the scattering matrix of the device. In previous works, this criterion was applied to different single hole orifices. The purpose of the present study is to apply the criterion to two orifices in series and to verify that the behavior of this system can be predicted from the scattering matrix of each individual orifice and of the straight pipe in-between. Measurements are done on an air test rig with an inner diameter of 3 cm, a Mach number of 2.6 × 10−2 and a Reynolds number of 104. Different distances between orifices are characterized. The study of the influence of the second orifice on the whistling criterion shows an enhancement of the whistling potential and a shift of the main potential whistling frequency. A fair agreement is found between experimental and predicted results. Characterization of orifices in series is then possible from the coefficients of the scattering matrix of one orifice and an appropriate condition on the distance between the orifices.

Uniqueness of Solutions to Variationally Formulated Acoustic Radiation Problems

1990 ◽  
Vol 112 (2) ◽  
pp. 263-267 ◽  
Author(s):  
Xiao-Feng Wu ◽  
Allan D. Pierce
Keyword(s):  
Acoustic Radiation ◽  
Axial Direction ◽  
Acoustic Power ◽  
Normal Derivative ◽  
Surface Velocity ◽  
Finite Cylinder ◽  
Uniqueness Of Solutions ◽  
Integral Theorem ◽  
Kirchhoff Integral

Determination of the surface acoustic pressure given the surface velocity of a vibrating body can be formulated in various ways. However, for some such formulations such as the surface Helmholtz integral equation, solutions are not unique at certain discrete frequencies. Such uniqueness problems can also be present for variational formulations of the problem, but the variational formulation based on the normal derivative of the Kirchhoff integral theorem has unique solutions for vibrating disks and plate-like bodies. For bodies of finite volume, but for which each surface point is vibrating in phase, the total radiated acoustic power is always unique, even though the pressure may not be. The latter conclusion is supported by numerical calculations based on the Rayleigh-Ritz technique for the case of a finite cylinder vibrating as a rigid body in the axial direction.

DETERMINATION OF THE NOISE POWER GENERATED BY THE POWDER SUPERSONIC JETS (SSJ)

Akustika ◽  
2020 ◽  
Vol 36 (36) ◽  
pp. 17-21
Author(s):  
Anatoly Kochergin ◽  
Valeeva Ksenia
Keyword(s):  
Solid Fuel ◽  
Sound Pressure ◽  
Experimental Studies ◽  
Supersonic Jet ◽  
Acoustic Power ◽  
Small Scale ◽  
Noise Power ◽  
Rocket Engines ◽  
Pressure Pulsations

The paper analyzes the results of experimental studies of the parameters of acoustic fields generated by the jets of small-scale solid fuel rocket engines (SFRE). The field of isobars of sound pressure created by a supersonic jet (SSJ) is considered. To identify the most correct approach to determining the acoustic power of the SSJ, a numerical integration of the power of pressure pulsations along the length of the jet was performed.

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