Modeling and Experimental Investigation of Tire Cavity Noise Generation Mechanisms for a Rolling Tire

2009 ◽  
Vol 2 (1) ◽  
pp. 1414-1423 ◽  
Author(s):  
Z. C. Feng ◽  
Perry Gu ◽  
Yongjian Chen ◽  
Zongbao Li
Keyword(s):  
Experimental Investigation ◽  
Noise Generation ◽  
Generation Mechanisms ◽  
Tire Cavity Noise

An Experimental Investigation of Sunroof Buffeting Characteristics of a Sedan

2012 ◽  
Vol 226-228 ◽  
pp. 247-251 ◽  
Author(s):  
Yin Zhi He ◽  
Zhi Gang Yang
Keyword(s):  
Experimental Investigation ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Resonance Frequency ◽  
Test Point ◽  
Noise Generation ◽  
Short Introduction ◽  
Wind Speeds ◽  
Operating Modes ◽  
Generation Mechanisms

After a short introduction about vehicle wind buffeting noise generation mechanisms, sunroof buffeting characteristics of a production sedan under different wind speeds and operating modes are investigated through full-scale aeroacoustic wind tunnel tests. As sunroof fully open, the severest buffeting effect occurs at wind speed 50kph, with the peak SPL 122dB and the corresponding resonance frequency 18Hz for the test point at the front row. From ca. 60kph it seems that the buffeting effect disappeared. As sunroof tilt, the severest buffeting effect occurs at wind speed equal or less than 30kph, the resonance frequency equal or less than 15Hz. From ca. 40kph the buffeting effect almost disappeared. Whether sunroof fully open or tilt, the resonance frequency increases all along as wind speed goes up till the buffeting effect disappeared (less than 20Hz). Different test positions at the front row or back row show very similar buffeting characteristics.

scholarly journals An experimental investigation of the use of an outlet silencer to quiet ejectors

2020 ◽  
Vol 19 (1-2) ◽  
pp. 4-37
Author(s):  
Gerard Desmarais ◽  
Joana Rocha
Keyword(s):  
Experimental Investigation ◽  
Flow Rate ◽  
Practical Method ◽  
Noise Generation ◽  
Small Drop ◽  
Noise Levels ◽  
Minimal Impact ◽  
Natural Modes ◽  
Air Ejector ◽  
Generation Mechanisms

Ejectors are simple fluid movers and mixers used in a range of industries; however, the attractiveness of their simplicity can be offset by high levels of noise generation. This work experimentally investigates the use of a silencer affixed to the outlet of a subsonic air–air ejector as a means of quieting the ejector. An emphasis is placed on finding a silencer design which has a minimal impact on the mass flow rate exhausting from the ejector (pumping performance). This paper discusses the results of 10 different silencer designs, tested in an attempt to further understand noise generation mechanisms and to find a practical method to reduce the noise of ejectors. It is found that the placement of a perforated cone at the mid-length of the silencer is the only solution tested which provides a significant acoustic advantage with only a small drop in pumping performance. Other solutions tested provide either no acoustic advantage or have too great of a reduction in pumping performance. It is found that the size and shape of the ejector can be designed in such a way to reduce the overlap of natural modes and thus the overall noise levels of the ejector caused by high levels of resonance. The use of acoustic foam to dampen acoustic natural modes proves that the natural modes of the ejector are a significant contributor to the overall noise levels.

Surface Topography and Noise Emission in Gearboxes

1997 ◽  
Author(s):  
Naser Amini ◽  
B. G. Rosén
Keyword(s):  
Experimental Investigation ◽  
Total Energy ◽  
Surface Topography ◽  
Noise Generation ◽  
Test Rig ◽  
Noise Emission ◽  
Applied Torque ◽  
Surface Topographies ◽  
Before And After ◽  
Noise Assessment

Abstract This paper, by the experimental investigation, deals with the effect of different surface topographies on noise generation in gears. Results from the noise assessment of one gear before and after honing are discussed. The honing operation was applied to the gear after the grinding. The gear was tested in an actual gearbox, operated in a test rig. Running conditions were systematically changed during the test; however, the same conditions were utilized for the gear before and after honing. The aim of the study was to identify the mechanism of the expected noise reduction, with surfaces being evaluated in 3D. The following results have been obtained: The total energy in the noise decreases significantly. The magnitude of the tooth-mesh frequency dose not change, but the level of its higher harmonics decreases significantly. These reductions are especially significant, when running at higher rotational speeds or when the applied torque is increased.

scholarly journals Exterior Noise Due to Interaction of Tyre-Thermoplastic Transverse Rumble Strips

2017 ◽  
Vol 42 (3) ◽  
pp. 449-457 ◽  
Author(s):  
Zaiton Haron ◽  
Mohd Hanifi Othman ◽  
Lim Meng Hee ◽  
Khairulzan Yahya ◽  
Mohd Rosli Hainin ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Surface Texture ◽  
Sound Level ◽  
Vehicle Speed ◽  
Noise Generation ◽  
Octave Band ◽  
Trade Off ◽  
Low Speed ◽  
The Public ◽  
Generation Mechanisms

AbstractTransverse rumble strips (TRS) are a common choice to reduce vehicle speed and increase driver alertness on roadways. However, there is a potential trade-off using them on rural roadway due to the noise problem created when vehicles go over the strips. The present study investigated the noise level, spectral analysis, and the possible noise generation mechanism when the TRS is hit by a vehicle. Tenraised- rumbler (RR) and three-layer-overlapped (TLO) TRS were selected in this study as they have received complaints from the public. Results showed that RR generated a relatively higher noise and impulse at a low speed, and increased sound level in each octave band. Based on these results, RR may irritate human ears even when the vehicle travels at a low speed. It was found that RR increased all noise generation mechanisms of tyre-pavement interaction whilst TLO increased structural resonance, sidewall and surface texture vibration.

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