NOISE CONTROL, REDUCTION AND CANCELLATION SOLUTIONS IN ENGINEERING Edited by Daniela Siano Noise Control, Reduction and Cancellation Solutions in Engineering Edited by Daniela Siano Published by InTech Janeza Trdine 9, 51000 Rijeka, Croatia Copyright © 2012 InTech All chapters are Open Access distributed under the Creative Commons Attribution 3.0 license, which allows users to download, copy and build upon published articles even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. After this work has been published by InTech, authors have the right to republish it, in whole or part, in any publication of which they are the author, and to make other personal use of the work. Any republication, referencing or personal use of the work must explicitly identify the original source. As for readers, this license allows users to download, copy and build upon published chapters even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. Notice Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher. No responsibility is accepted for the accuracy of information contained in the published chapters. The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book. Publishing Process Manager Molly Kaliman Technical Editor Teodora Smiljanic Cover Designer InTech Design Team First published March, 2012 Printed in Croatia A free online edition of this book is available at www.intechopen.com Additional hard copies can be obtained from orders@intechweb.org Noise Control, Reduction and Cancellation Solutions in Engineering, Edited by Daniela Siano p. cm. 978-953-307-918-9 Contents Preface IX Part 1 Background of Active Noise Control 1 Chapter 1 Noise Sources in the City: Characterization and Management Trends 3 Alice Elizabeth González Part 2 Theory 27 Chapter 2 Adaptive Fractional Fourier Domain Filtering in Active Noise Control 29 Sultan Aldırmaz and Lütfiye Durak–Ata Chapter 3 Analysis of Quiet Zones in Diffuse Fields 47 Wen-Kung Tseng Chapter 4 Unsteady Flows in Turbines 71 Lei Qi and Zhengping Zou Part 3 Experimental Tests 99 Chapter 5 Vibration Source Contribution Evaluation of a Thin Shell Structure Based on ICA 101 Wei Cheng, Zhousuo Zhang and Zhengjia He Chapter 6 Advanced Vibro-Acoustic Techniques for Noise Control in Helicopters 123 Emiliano Mucchi, Elena Pierro and Antonio Vecchio Chapter 7 Psychophysiological Experiments on Extent of Disturbance of Noises Under Conditions of Different Types of Brain Works 147 Sohei Tsujimura and Takeshi Akita VI Contents Chapter 8 The Convergence Analysis of Feedforward Active Noise Control System 159 Guoyue Chen Chapter 9 Synergistic Noise-By-Flow Control Design of Blade-Tip in Axial Fans: Experimental Investigation 177 Stefano Bianchi, Alessandro Corsini and Anthony G. Sheard Chapter 10 Assessment of Acoustic Quality in Classrooms Based on Measurements, Perception and Noise Control 201 Paulo Henrique Trombetta Zannin, Daniele Petri Zanardo Zwirtes and Carolina Reich Marcon Passero Chapter 11 From Noise Levels to Sound Quality: The Successful Approach to Improve the Acoustic Comfort 233 Eleonora Carletti and Francesca Pedrielli Chapter 12 Application of Sound Level for Estimating Rock Properties 267 Harsha Vardhan and Rajesh Kumar Bayar Preface Noise Control is one of the most important subjects in acoustic engineering and one of the prevalent health hazards in the industry, and in the city. A comprehensive overview, application of principles, and concept of noise control, in a wide variety of fields, is found in this book. The authors provide a range of practical applications of current noise control strategies and technologies offering to the reader their research in this field with concrete examples and results of actual experiments. Literature widely quoted in this book is full of examples of more advanced applications. Additionally, the literature is more fully developed. The main purpose is to provide technical information on how noise can be controlled easily in respect of passive control. There is an extensive treatment of important problems, such as sound in enclosures, methods for noise reduction, hearing, speech intelligibility, and psycho acoustic criteria for comfort, for satisfactory speech intelligibility, and for pleasant listening conditions. This book can be intended as a reference source for researchers, engineers, and acoustic specialists that want to develop a practical approach to controlling noise occurring in different fields. Dr. Siano Daniela, Fluidynamic and Combustion Division, Istituto Motori CNR, Italy [...]... to diminish the traffic noise in the cities can reach good results in this sense; it is the case of the traffic 6 Noise Control, Reduction and Cancellation Solutions in Engineering regulation known as “pico y placa”1 in Medellín city, Colombia (Ríos Valencia, 2008) Some aspects that should be taken into account when dealing with traffic noise in the cities are discussed in Section 4 2.2 Ambient noise. .. different points of measurement and hours, with and without nightclubs operation 16 Noise Control, Reduction and Cancellation Solutions in Engineering Main results are shown in figures 2 and 3, and are summarized next (González et al., 2006): Traffic is directly related to the activity of the nightclubs When they are not in operation, the traffic is very low and the same happens with the noise levels... composition is in correspondence with the “standardized traffic noise spectrum” that is defined both by octave bands levels and by third octave bands levels at standard EN1793-3 Given a noise level value expressed in dBA, its spectral composition in octave bands or in third octave bands (also expressed in dBA) shall be found by adding band to band the set of tabulated values that define the standardized... Control, Reduction and Cancellation Solutions in Engineering indicator, where the trespassing of any relevant regulation limit value will be indicated, also the number of people affected in a specific area or the number of households exposed to certain values of a selected noise indicator in a specific area” It is stated that the information to the public should be given in a clear, comprehensible and easily... exposed information Not only its reliability becomes widely increased, but also its possible applications get greatly expanded (González, 2011) 6 Conclusion Noise management involves great challenges: if one problem has seemed easy to solve, certainly it has not been raised properly 24 Noise Control, Reduction and Cancellation Solutions in Engineering To influence on politics about noise and to improve... present an overview as complete as possible of each case, taking into account not only legal and technical issues, but also health, ethics, economics and social 12 Noise Control, Reduction and Cancellation Solutions in Engineering ones Management of urban noise is not an easy task Referring to popular celebrations, he says: “the occasional noise is noise anyway“ (Defensor del Pueblo de Madrid, 2005) 90,0... passes the line BB2 in third gear is greater than 61 km/h Table 3 Current limit values for sound level of moving vehicles in the European Union 2 According with ISO standard test 18 Noise Control, Reduction and Cancellation Solutions in Engineering MERCOSUR maximum noise for stationary and accelerating vehicle 1st phase implantation Category 2nd phase implantation 01/01/2001 01/01/2000 Under 80 cm3 77... ciudad de Arequipa y su incidencia en la salud de la población más expuesta, Proceedings of International Seminar on Environmental Noise ISBN: 978-958-44-3029-8, Medellín, Colombia, March 2008 26 Noise Control, Reduction and Cancellation Solutions in Engineering Miyara, F (2007) “Ruido, juventud y derechos humanos” I Congreso Latinoamericano de Derechos Humanos Rosario, Argentine, 2007 Miyara, F (2008)... people who is out of the local and to avoid the occurrence of unwanted noises in the street (González et al., 2006; González &.Echeverri, 2008) 14 Noise Control, Reduction and Cancellation Solutions in Engineering About the operational problems related to pink zones, there are two major issues: the accumulation of youths outside the nightlife clubs, and the circulating vehicles -or even parked ones-... emblematic symbols that remained strongly associated with progress and economic improvement for a long time, even if these benefits were only for a little privileged part of the society 4 Noise Control, Reduction and Cancellation Solutions in Engineering Technological development began to generate increasingly powerful and, perhaps, progressively also cheaper- sources of noise that people at first . NOISE CONTROL, REDUCTION AND CANCELLATION SOLUTIONS IN ENGINEERING Edited by Daniela Siano Noise Control, Reduction and Cancellation Solutions in Engineering Edited. subjects in acoustic engineering and one of the prevalent health hazards in the industry, and in the city. A comprehensive overview, application of principles, and concept of noise control, in a. online edition of this book is available at www.intechopen.com Additional hard copies can be obtained from orders@intechweb.org Noise Control, Reduction and Cancellation Solutions in Engineering,