NAVAL POSTGRADUATE SCHOOL Monterey, California THESIS COMPU TER PROGRAMS SUPPORTING INSTRUCTION IN ACOUSTICS by Thomas Alan Green December, 1996 Thesis Advisor: James V. Sanders Co- Advisor: Anthony A. Atchley Approved for public release; distribution is unlimited. niins PY K^"OX LSBRARY nEostgraduateschooi mWtm CA 93943-5101 REPORT DOCUMENTATION PAGE FormApprovedOMBNo.0704-0188 Publicrqx>rtingburdenforthiscollectionofinfonnationisestimatedtoaverage1hourperresponse,includingthetimeforreviewinginstruction,searchingexistingdata sources,gatheringandmaintainingthedataneeded,andcompletingandreviewingthecollectionofinformation. Sendcommentsregardingthisburdenestimateoranyother aspectofthiscollectionofinformation,includingsuggestionsforreducingthisburden,toWashingtonHeadquartersServices,DirectorateforInformationOperationsand Reports, 1215JefifersonDavisHighway,Suite1204,Arlington,VA22202-4302,andtotheOfiBceofManagementandBudget,PaperworkReductionProject(0704-0188) WashingtonDC20S03. 1. AGENCYUSEONLY (Leaveblank) 2. REPORTDATE 3. REPORTTYPEANDDATES COVERED December 1996 Master's Thesis 4. TITLEAND SUBTITLE COMPUTER PROGRAMS SUPPORTING 5. FUNDINGNUMBERS INSTRUCTION IN ACOUSTICS 6. AUTHOR(S)Thomas A. Green 7. PERFORMINGORGANIZATIONNAME(S)ANDADDRESS(ES) 8. PERFORMING Naval Postgraduate School ORGANIZATION Monterev CA 93943-5000 REPORTNUMBER SPONSORING/MONITORINGAGENCYNAME(S)ANDADDRESS(ES) 10. SPONSORING/MONITORING AGENCYREPORTNUMBER 11. SUPPLEMENTARYNOTES The views expressed inthis thesis arethose ofthe author and do not reflectthe official policy or position ofthe Department ofDefense orthe U.S. Government. 12a. DISTRIBUTION/AVAILABILITYSTATEMENT 12b. DISTRIBUTIONCODE Approved for public release; distribution is unlimited. 13. ABSTRACT (maximum 200words) Traditionally, the study ofmechanical vibration and sound wave propagation has been presentedthrough textbooks, classroom discussion and laboratory experiments. However, in today's academic environment, students have access to high performance computing facilities which can greatly augmentthe learning process. This thesis provides computer algorithms for examining selected topics drawn from thetext. Fundamentals of & Acoustics, Third Edition, John Wiley Sons, Inc., by Kinsler, Frey, Coppens and Sanders, (KFCS). Emphasis is on usingthe modeling and simulation capability ofthe programing language, MATLAB^^, to illustrate and analyze complex physical principles which may seem obscure on the printed page yet are challenging or inconvenient to duplicate in the laboratory. This is not a passive recitation ofacoustic phenomena, but complements KFCS with interactive student participation. The usefubiess ofthese programs and any weaknesses in format or content needs to be tested in the classroom. 14. SUBJECTTERMS acoustics, MATLAB, computer, vibration 15. NUMBEROF PAGES240 16. PRICECODE 17. SECURITY CLASSIFICA- SECURITYCLASSIFI- 19. SECURITYCLASSIFICA- 20. LIMITATIONOF TIONOFREPORT CATIONOFTfflSPAGE TIONOFABSTRACT ABSTRACT UL Unclassified Unclassified Unclassified NSN7540-01-280-5500 StandardForm298 (Rev. 2-89) PrescribedbyANSIStd.239-18298-102 11 Approved for public release; distribution is unlimited. COMPUTER PROGRAMS SUPPORTING INSTRUCTION IN ACOUSTICS Thomas A. Green Lieutenant Commander, United States Navy B.S., U.S. Naval Academy, 1981 Submitted in partial fulfillment ofthe requirements for the degree of MASTER OF SCIENCE IN ENGINEERING ACOUSTICS from the NAVAL POSTGRADUATE SCHOOL /December 1996 / DUDLEY KNOX L18RARY NAVAL POSTGaADUATE SCHOOI MONTEREY CA 93943.5101 ABSTRACT Traditionally, the study ofmechanical vibration and sound wave propagation has been presented through textbooks, classroom discussion and laboratory experiments. However, in today's academic environment, students have access to high performance computing facilities which can greatly augment the learning process. This thesis provides computer algorithms for examining selected topics drawn from the text. Fundamentals ofAcoustics, & Third Edition, John Wiley Sons, Inc., by Coppens, Frey, Kinsler and Sanders, (KFCS). Emphasis is on using the modeling and simulation capability ofthe programing language, MATLAB™ to illustrate and analyze complex physical principles which may seem obscure on the printed page yet are challenging or inconvenient to duplicate in the laboratory. This is not a passive recitation ofacoustic phenomena, but complements KFCS with interactive student participation. The usefulness ofthese programs and any weaknesses in format or content needs to be tested in the classroom. VI TABLE OF CONTENTS INTRODUCTION I. 1 BACKGROUND A. 1 PURPOSE B. 1 C. ESSENTIAL REQUIREMENTS 2 1. Text 2 2. Software 2 D. FILE NAME CONVENTION 3 1. Script Files 3 2. Function Files 3 E. DISK CONTENTS 4 F. TYPOGRAPfflC STYLES 4 SIMPLE HARMONIC OSCILLATOR 7 II. CONCEPT A. 7 B. SALIENT FEATURES OF c01s02.m 7 1. Amplitude 8 2. Frequency and Period 8 ALGORITHM C. c01s02.m 8 III. INITIAL CONDITIONS 11 vu CONCEPT A. 11 B. SALIENT FEATURES OF c01s03.m 12 1. Initial Displacement 12 2. Initial Velocity 12 ALGORITHM C. c01s03.m 13 COMPLEX EXPONENTIAL IV. 15 A. CONCEPT .......15 B. ALGORITHM LIMITATIONS 16 C. SALIENT FEATURES OF c01s05.m 16 1. Phaser Position 16 2. Phasor Magnitude 16 ALGORITHM D. c01s05.m 17 V. DAMPED HARMONIC OSCILLATOR 19 CONCEPT A. 19 B. SALIENT FEATURES OF c01s06.m 20 1. Temporal Absorption Coefficient 20 2. Initial Conditions 21 ALGORITHM C. c01s06.m 21 VI. FORCED OSCILLATIONS 25 viii