Energy Characteristics of Secondary Vortical Domain of Axisymmetric Hydrodynamic Sound Source

2004 ◽  
Vol 31 (1) ◽  
pp. 65-73
Author(s):  
Yu. M. Dudzinskii ◽  
A. A. Nazarenko
Akustika ◽  
2019 ◽  
Vol 34 ◽  
pp. 88-94
Author(s):  
Alexander Antonov ◽  
Irina Matveeva ◽  
Igor Shubin ◽  
Ilya Tsukernikov

The choice and acoustic efficiency of construction and acoustic means of noise control is determined on the basis of calculations of changes in the spatio-temporal characteristics of the pulses of sound energy emitted by the sound source. The paper proposes a combined computational model for estimating the energy characteristics of pulse noise and their spatiotemporal changes. The model describes the formation and distribution of the reflected sound energy of pulses in the mirror-scattered reflection of sound from the fences. The principles of construction of the computational model and the computer program implementing it are stated. Evaluation of the computational model is performed by comparative analysis of experimental and computational data obtained by the action of a pulsed noise source in complex geometrically shaped rooms. It is found that the calculated graphs of the decay of the reflected pulse energy in time coincide with the experimentally determined declines.


1999 ◽  
Vol 58 (3) ◽  
pp. 170-179 ◽  
Author(s):  
Barbara S. Muller ◽  
Pierre Bovet

Twelve blindfolded subjects localized two different pure tones, randomly played by eight sound sources in the horizontal plane. Either subjects could get information supplied by their pinnae (external ear) and their head movements or not. We found that pinnae, as well as head movements, had a marked influence on auditory localization performance with this type of sound. Effects of pinnae and head movements seemed to be additive; the absence of one or the other factor provoked the same loss of localization accuracy and even much the same error pattern. Head movement analysis showed that subjects turn their face towards the emitting sound source, except for sources exactly in the front or exactly in the rear, which are identified by turning the head to both sides. The head movement amplitude increased smoothly as the sound source moved from the anterior to the posterior quadrant.


2013 ◽  
Author(s):  
Susanne Mayr ◽  
Gunnar Regenbrecht ◽  
Kathrin Lange ◽  
Albertgeorg Lang ◽  
Axel Buchner

2013 ◽  
Author(s):  
Agoston Torok ◽  
Daniel Mestre ◽  
Ferenc Honbolygo ◽  
Pierre Mallet ◽  
Jean-Marie Pergandi ◽  
...  

2020 ◽  
Vol 64 (1-4) ◽  
pp. 137-145
Author(s):  
Yubin Xia ◽  
Dakai Liang ◽  
Guo Zheng ◽  
Jingling Wang ◽  
Jie Zeng

Aiming at the irregularity of the fault characteristics of the helicopter main reducer planetary gear, a fault diagnosis method based on support vector data description (SVDD) is proposed. The working condition of the helicopter is complex and changeable, and the fault characteristics of the planetary gear also show irregularity with the change of working conditions. It is impossible to diagnose the fault by the regularity of a single fault feature; so a method of SVDD based on Gaussian kernel function is used. By connecting the energy characteristics and fault characteristics of the helicopter main reducer running state signal and performing vector quantization, the planetary gear of the helicopter main reducer is characterized, and simultaneously couple the multi-channel information, which can accurately characterize the operational state of the planetary gear’s state.


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