ISO/TR TECHNICAL REPORT 11688-2 First edition 1998-09-01 Acoustics Recommended practice for the design of low-noise machinery and equipment - Part 2: Introduction to the physics of low-noise design Acoustique Pratique recommandée pour la conception de machines et équipements a bruit réduit- Partie 2: Introduction a la physique de la conception a bruit reduit ISO Reference number ISO/TR 11688-2:1998(E) Not for Resale ISO/TR 11688-2:1998(E) Contents 1 Scope 1 References. 2 1 3 Definitions 1 4 Acoustical modelling. 1 Control of airborne and liquid-borne noise.. 2 5.1 Generation of fluid-dynamic noise... 2 5.2 Noise control measures . 8 6 Control of structure-borne sound. 10 6.1 Model of sound generation ... 10 6.2 Internal sources ..... 15 6.3 Transmission of structure-borne sound 18 6.4 Control of structure-borne sound transmission by damping ..... 28 6.5 Radiation... 30 7Analysis by measurement methods 35 7.1 Purpose of the analysis.. 35 7.2 Internal sources . 36 7.3 Transmission paths.. 36 7.4 Radiation... 36 7.5 Summary of procedures for the analysis of existing machinery by measurement methods.. 37 8Analysis by computational methods . 39 8.1 Purpose of the analysis... 39 8.2 Deterministic methods.. 39 8.3 Statistical methods.. 39 8.4 Applicability of computational methods . 39 Annex A Example of the estimation of airborne sound emission ofamachinecausedbystructure-borneandairbornesound emission from a component. 41 Annex B Giossary. 44 Bibliography.... 46 @ISO1998 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International OrganizationforStandardization Case postale 56 . CH-1211 Geneve 20 · Switzerland Internet [email protected] Printed in Switzerland Copyright International Organization for Standardization se from IHS Not for Resale ISO/TR 11688-2:1998(E) @ ISO Foreword IsO (the International Organization for Standardization) is a worldwide preparing International Standards is normally carried out through IsO technical committees. Each member body interested in a subject for which atechnicalcommitteehasbeenestablishedhastherighttoberepresented on that committee. International organisations, governmental and non- governmental, in liaison with isO, also take part in the work. isO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The main task of technical committees is to prepare International Standards, but in exceptional circumstances a technical committee may propose the publication of a Technical Report of one of the following types: type 1, when the required support cannot be obtained for the publication of an International Standard, despite repeated efforts; type 2, when the subject is still under technical development or where of an agreement on an International Standard; type3,whena technical committeehas collecteddataof adifferent kind from that which is normally published as an International Standard ("state of the art", for example) Technical Reports of types 1 and 2 are subject to review within three years of publication, to decide whether they can be transformed into International reviewed until the data they provide are considered to be no longer valid or useful. ISO/TR 11688-2, which is a Technical Report of type 3, was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise. IsO 11688 consists of the following parts, under the general title Acoustics Recommendedpracticeforthe design oflow-noisemachineryand equipment: Part 1: Planning Part 2: Introduction to the physics of low-noise design ili