A New Method of Characterizing Wind Noise Sources and Body Response for a Detailed Analysis of the Noise Transmission Mechanism

2016 ◽  
Vol 9 (2) ◽  
pp. 475-481
Author(s):  
Tadayoshi Fukushima ◽  
Hitoshi Takagi ◽  
Toshio Enomoto ◽  
Hiroyuki Sawada ◽  
Tomoyuki Kaneda
Keyword(s):  
Detailed Analysis ◽  
Transmission Mechanism ◽  
New Method ◽  
Noise Sources ◽  
Wind Noise ◽  
Noise Transmission ◽  
Body Response

Mechanism of interior noise generation in high-speed vehicle based on anti-noise operational transfer path analysis

2020 ◽  
Vol 235 (1) ◽  
pp. 273-287
Author(s):  
Ningning Liu ◽  
Yuedong Sun ◽  
Yansong Wang ◽  
Pei Sun ◽  
Wenwu Li ◽  
...  
Keyword(s):  
Path Analysis ◽  
High Speed ◽  
Noise Signal ◽  
Interior Noise ◽  
Analysis Model ◽  
Noise Sources ◽  
Wind Noise ◽  
Transfer Path ◽  
Transfer Path Analysis ◽  
Path Analysis Model

Owing to the continuous development of the automobile industry, increasingly stringent performance requirements for noise, vibration, and harshness of automobiles are being presented. Interior noise control in high-speed vehicles has not been adequately addressed, owing to the complex mechanism of noise generation. As simulations performed previously focused on vehicle wind noise and tyre noise cannot adequately predict the effect on passenger ear-side noise, these issues are investigated in this study. Their effects on passengers are investigated using transfer path analysis. An anti-noise operational transfer path analysis is proposed to study noise generated in high-speed vehicles. The established anti-noise operational transfer path analysis model can eliminate crosstalks between noise source signals of different transmission paths. The model is validated by comparing the measured and calculated values of the anti-noise operational transfer path analysis model. The coherence of the input noise signal and the ear-side noise signal of the passenger is assessed using coherence analysis. By calculating and categorising the contributions of different noise sources in different locations and types, the main noise sources affecting passenger comfort are determined. The result indicates that the main noise sources affecting the passenger’s ear-side noise change from engine noise to left-A wind noise and tyre radiation noise with increasing vehicle speed, in which the proportion also increase. The proposed anti-noise operational transfer path analysis is suitable for the interior-noise analysis of high-speed vehicles, and this study may serve as a reference for future studies regarding active and passive noise control in high-speed vehicles.

scholarly journals The Missing Transmission Mechanism in the Monetary Explanation of the Great Depression

2013 ◽  
Vol 103 (3) ◽  
pp. 66-72 ◽  
Author(s):  
Christina D Romer ◽  
David H Romer
Keyword(s):  
Interest Rates ◽  
Detailed Analysis ◽  
Great Depression ◽  
Federal Reserve ◽  
Transmission Mechanism ◽  
Monetary Shocks ◽  
Real Interest Rates ◽  
The Great Depression ◽  
Nominal Interest Rates ◽  
Business Week

This paper examines the missing transmission mechanism in Friedman's and Schwartz's monetary explanation of the Great Depression. We review the challenge provided by the decline in nominal interest rates in the early 1930s, and show that the monetary explanation requires not just that there were expectations of deflation, but that they were caused by monetary contraction. Using a detailed analysis of Business Week magazine, we find evidence that monetary contraction and Federal Reserve policy contributed to expectations of deflation during the downturn. This suggests that monetary shocks may have depressed spending and output in part by raising real interest rates.

scholarly journals On The Brightness Wave of Electroluminescent ZnS (Powders and Single Crystals)

1967 ◽  
Vol 22 (10) ◽  
pp. 1504-1507
Author(s):  
A. Levialdi ◽  
N. Romeo ◽  
G. Saitta
Keyword(s):  
Temperature Dependence ◽  
Detailed Analysis ◽  
Single Crystals ◽  
Spectral Composition ◽  
New Method ◽  
Secondary Peak ◽  
Enhancement Effect ◽  
Brightness Wave ◽  
Harmonic Components

We describe a new method for analyzing the brightness wave which accounts for the temperature-dependence of the secondary peak, provides a different interpretation of the enhancement effect in ac+dc and gives a more detailed analysis of the spectral composition of the different harmonic components.

Development of Prediction Method for Wind Noise Caused by Airflow Around Front Pillar

2011 ◽  
Author(s):  
Yasuhiko Okutsu ◽  
Naoki Hamamoto ◽  
Robert Powell ◽  
Long Wu
Keyword(s):  
High Frequency ◽  
Noise Level ◽  
High Speed ◽  
Prediction Method ◽  
Noise Sources ◽  
Wind Noise ◽  
Front Passenger ◽  
Passenger Seat ◽  
Simulation Results ◽  
Head Area

To control high frequency wind noise upper than 1 kHz is important to ensure the comfort for a driver and passengers when vehicles cruise at high speed. Therefore the prediction method for high frequency wind noise inside a cabin has been required for development of a vehicle. This paper describes about the prediction method for high frequency wind noise from numerical simulation results. In this study, wind noise caused by airflow around a front pillar is predicted. We have predicted wind noise by visualizing noise sources and pressure fluctuation on vehicle surfaces in recent years. Although an inferior-to-superior relationship can be predicted from these results, it was difficult to estimate quantitative interior noise level. In this research, the SEA code is examined to predict such noise level. The SEA code has confirmed showing a qualitative and almost quantitative consistency of measured and calculated SPL at the head area of a front passenger seat.

Experimental Evaluation of Wind Noise Sources: A Case Study

1999 ◽  
Author(s):  
William B. Coney ◽  
Jen Y. Her ◽  
Keith Tomaszewicz ◽  
Kevin Y. Zhang ◽  
James A. Moore
Keyword(s):  
Experimental Evaluation ◽  
Noise Sources ◽  
Wind Noise

Localization and Identification of Vibroacoustic Sources of Gear Transmission Mechanism by Inverse Frequency Response Function

2012 ◽  
Vol 232 ◽  
pp. 437-444 ◽  
Author(s):  
Abbassia Derouiche ◽  
Nacer Hamzaoui ◽  
Taoufik Boukharouba
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
A Priori ◽  
Tangent Plane ◽  
Spur Gear ◽  
Gear Transmission ◽  
Transmission Mechanism ◽  
Noise Sources ◽  
Complex Phenomena

Our contribution in this work is to detect, localize and quantify the noise sources radiated by a spur gear transmission mechanism. The imaging technique is used; it is based on the acoustic inverse frequency response function (IFRF). The IFRF is based on the inversion of the transfer matrix built between the source points represented by their complex source strengths and listening points represented by the complex pressures measured by the hologram. The measurements were performed in a semi-anechoic room where the floor is concrete and the walls are covered with glass wool. The complex acoustic pressures are measured by an antenna with microphones regularly spaced; it is placed above the noisy mechanism. The reconstruction problem is therefore an inverse problem and is said ill-posed; thus, regularizations are needed to stabilize and to find the best solutions. As regularization technique, the Tikhonov method is applied and the regularization parameters are chosen according to the L-curve method. The goal is to reconstruct as accurately as possible the acoustic field radiated by the transmission mechanism on a fictive and tangent plane to the noisy mechanism considered open and sometimes closed. The results obtained showed that the sources were located with good approximation. The IFRF method is able to reconstruct the sound sources responsible for the noise radiated by the mechanism without any a priori information of the sources distribution, and the visualization of spatial acoustic fields facilitate the understanding of the complex phenomena of radiation.

Hybrid Technique for Underbody Noise Transmission of Wind Noise

2011 ◽  
Author(s):  
Philippe Moron ◽  
Andreas Hazir ◽  
Bernd Crouse ◽  
Robert Powell ◽  
Barbara Neuhierl ◽  
...  
Keyword(s):  
Hybrid Technique ◽  
Wind Noise ◽  
Noise Transmission

scholarly journals Automotive aeroacoustics: An overview

2017 ◽  
Vol 231 (9) ◽  
pp. 1177-1189 ◽  
Author(s):  
Nicholas Oettle ◽  
David Sims-Williams
Keyword(s):  
Broadband Noise ◽  
Major Influence ◽  
Noise Performance ◽  
Vehicle Interior ◽  
Noise Sources ◽  
Wind Noise ◽  
Distinctive Features ◽  
Aeroacoustic Noise ◽  
Cabin Noise ◽  
The Impact

Vehicle aeroacoustic performance has a major influence on customer perception and also has importance for safety and comfort. Wind noise performance was once differentiated by the quality of sealing. Today, achieving competitive wind noise performance also depends on minimising aeroacoustic noise sources generated by the vehicle form, and on attenuation in the noise pathway from sources on the exterior to the vehicle interior. The reduction in noise transmission, especially through glazed surfaces, will continue to play an important role in controlling cabin noise, with a particular emphasis on achieving attenuation efficiently in terms of component mass. The human brain is not only sensitive towards the level of steady broadband noise, but distinctive features such as tonality or modulation draw the attention of the vehicle occupant and impact negatively on perception. Complex indices are often required to define good wind noise performance. This includes the consideration of multiple frequency bands and effects of the range of yaw angles experienced on-road. A key to achieving future vehicle refinement is bringing together an understanding of unsteady onset flow conditions, their impact on cabin sound pressure level and modulation and, in turn, the impact of noise level and modulation on psychoacoustic perception.

4030 Evaluation of Automobile Wind Noise Sources Using Experiment and CFD

2006 ◽  
Vol 2006.2 (0) ◽  
pp. 389-390
Author(s):  
Ye LI ◽  
Naohiko KASAKI ◽  
Hiroyuki TSUNODA ◽  
Takaki NAKAMURA ◽  
Takahide NOUZAWA
Keyword(s):  
Noise Sources ◽  
Wind Noise
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