Acoustic radiation characteristics improvement according to the shape change of flat-plate display exciter speaker

2019 ◽  
Vol 145 (3) ◽  
pp. 1864-1864
Author(s):  
Hyung Woo Park ◽  
SungTae Lee ◽  
Kwanho Park
Keyword(s):  
Flat Plate ◽  
Acoustic Radiation ◽  
Shape Change ◽  
Radiation Characteristics

scholarly journals Effects of pipe casing structure on acoustic emission characteristics of underwater pyrotechnic combustion

2019 ◽  
Vol 39 (1) ◽  
pp. 149-157
Author(s):  
Jie Li ◽  
Jun Du ◽  
Xian Chen ◽  
Yanli Wang
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Acoustic Radiation ◽  
Structural Characteristics ◽  
Bubble Formation ◽  
Pressure Level ◽  
Radiation Characteristics ◽  
Acoustic Testing ◽  
Gas Volume ◽  
Broadband Sound

In order to investigate the acoustic radiation characteristics of underwater, a pipe casing was introduced and the effects of its main structural characteristics on underwater combustion acoustic radiation were studied by acoustic testing. The results show that the addition of the pipe casing significantly increased the sound pressure level of underwater pyrotechnic combustion, especially the peak of sound pressure level that was increased by 15.9 dB from 155.5 to 171.4 dB at the frequency of 125 and 100 Hz. But the addition of the pipe casing had little effect on the frequency. These results indicated that adding a pipe casing is effective for improving sound pressure level in underwater pyrotechnic combustion. An increase in nozzle diameter from 10 to 12.5 mm resulted in an increase of gas volume, so the peak of sound pressure level and broadband sound pressure level is higher. Changing the pipe casing direction to vertical downward will make the bubble formation period shorter, which will generate more bubbles and strong wake; the interaction between bubbles and wake results in a higher intensity of turbulence, which accounts for the coalescence and breakup of bubbles in the fluid. Besides, changing the diameter of pipe casing can be used to lower the frequency of underwater noise.

A Technique to Predict the Acoustic Radiation Characteristics of an Automobile Tire

1986 ◽  
Vol 14 (2) ◽  
pp. 102-115 ◽  
Author(s):  
C. Wright ◽  
G. H. Koopmann
Keyword(s):  
Close Agreement ◽  
Sound Pressure ◽  
Acoustic Radiation ◽  
Surface Velocity ◽  
Experimental Measurements ◽  
Far Field ◽  
Radiation Characteristics ◽  
Automobile Tire ◽  
Electrodynamic Vibrator ◽  
Field Sound

Abstract A technique to predict the acoustic radiation characteristics of the predominant structural modes of an automobile tire is presented. A stationary tire is excited by an electrodynamic vibrator and, through conventional modal analysis methods, a description of the surface velocity is obtained. With this information, and a representation of the tire geometry, numerical procedures are used to predict the acoustic surface intensity and field pressure, for a given frequency of interest, based on a Helmholtz integral formulation. Predicted far field sound pressure levels are in close agreement with experimental measurements taken in an anechoic chamber. This provided the necessary validation of the technique.

Acoustical Radiation Characteristics Test of Magnesium Alloy Sheets with Element Method

2014 ◽  
Vol 926-930 ◽  
pp. 375-378
Author(s):  
Ting Jin ◽  
Zheng Yin Ding
Keyword(s):  
Magnesium Alloy ◽  
Acoustic Radiation ◽  
Radiation Characteristics ◽  
Paper Advance ◽  
Structure Vibration ◽  
Connection Type ◽  
Thin Walled ◽  
Element Method

Structure vibration is one of the main causes of noise. Thin-walled workpiece has a smaller stiffness,it will easily produce vibrations at work ,and become a source of noice. It is very necessary to study acoustic radiation characteristics of plat,so can we effectively control the structure and connection type of panel structure to change acoustical radiation characteristics.This paper advance a element method to test acoustical radiation characteristics of plat,and take experiment with magnesium alloy sheets.

Acoustic Radiation of Subsonic Jets at the Vicinity of an Inclined Flat Plate

2018 ◽  
Author(s):  
Petrônio A. Nogueira ◽  
José R. Sirotto ◽  
Renato F. Miotto ◽  
André V. Cavalieri ◽  
Julio A. Cordioli ◽  
...  
Keyword(s):  
Flat Plate ◽  
Acoustic Radiation

scholarly journals Power Transformer Spatial Acoustic Radiation Characteristics Analysis under Multiple Operating Conditions

Energies ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 74 ◽  
Author(s):  
Liming Ying ◽  
Donghui Wang ◽  
Jinwei Wang ◽  
Guodong Wang ◽  
Xiaowen Wu ◽  
...  
Keyword(s):  
Acoustic Radiation ◽  
Power Transformer ◽  
Operating Conditions ◽  
Radiation Characteristics ◽  
Characteristics Analysis
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