47 Texts in Applied Mathematics Editors J.E.Marsden L.Sirovich S.S.Antman Advisors G.Iooss P.Holmes D.Barkley M.Dellnitz P.Newton Springer NewYork Berlin Heidelberg HongKong London Milan Paris Tokyo This page intentionally left blank Hilary Ockendon John R. Ockendon Waves and Compressible Flow With60Figures 1 3 HilaryOckendon JohnR.Ockendon OxfordCentreforIndustrialand OxfordCentreforIndustrialand AppliedMathematics AppliedMathematics 24–29St.Giles 24–29St.Giles OxfordOX13LB OxfordOX13LB UK UK [email protected] [email protected] SeriesEditors J.E.Marsden L.Sirovich ControlandDynamicalSystems,107–81 DivisionofAppliedMathematics CaliforniaInstituteofTechnology BrownUniversity Pasadena,CA91125 Providence,RI02912 USA USA [email protected] [email protected] S.S.Antman DepartmentofMathematics and InstituteofPhysicalScience andTechnology UniversityofMaryland CollegePark,MD20742-4015 USA [email protected] MathematicsSubjectClassification(2000):76-02,76Nxx,76Bxx LibraryofCongressCataloging-in-PublicationData Ockendon,Hilary. Wavesandcompressibleflow/HilaryOckendon,JohnR.Ockendon. p.cm.—(Textsinappliedmathematics;v.47) Includesbibliographicalreferencesandindex. ISBN0-387-40399-X(alk.paper) 1.Wavemotion,Theoryof. 2.Fluiddynamics. 3.Compressibility. I.Title. II.Textsin appliedmathematics;47. QA927.O252003 (cid:1) 532.0535—dc21 2003054314 ISBN0-387-40399-X Printedonacid-freepaper. (cid:1)c 2004Springer-VerlagNewYork,Inc. Allrightsreserved.Thisworkmaynotbetranslatedorcopiedinwholeorinpartwithoutthe writtenpermissionofthepublisher(Springer-VerlagNewYork,Inc.,175FifthAvenue,NewYork, NY10010,USA),exceptforbriefexcerptsinconnectionwithreviewsorscholarlyanalysis.Usein connectionwithanyformofinformationstorageandretrieval,electronicadaptation,computer software,orbysimilarordissimilarmethodologynowknownorhereafterdevelopedisforbidden. Theuseinthispublicationoftradenames,trademarks,servicemarks,andsimilarterms,evenif theyarenotidentifiedassuch,isnottobetakenasanexpressionofopinionastowhetherornot theyaresubjecttoproprietaryrights. PrintedintheUnitedStatesofAmerica. (BPR/MVY) 9 8 7 6 5 4 3 2 1 SPIN10938317 Springer-VerlagisapartofSpringerScience+BusinessMedia springeronline.com Series Preface Mathematicsisplayinganevermoreimportantroleinthephysicalandbiolog- ical sciences, provoking a blurring of boundaries between scientific disciplines and a resurgence of interest in the modern as well as the classical techniques of applied mathematics. This renewal of interest, both in research and teach- ing, has led to the establishment of the series Texts in Applied Mathematics (TAM). The development of new courses is a natural consequence of a high level of excitement on the research frontier as newer techniques, such as numerical andsymboliccomputersystems,dynamicalsystems,andchaos,mixwithand reinforce the traditional methods of applied mathematics. Thus, the purpose ofthistextbookseriesistomeetthecurrentandfutureneedsoftheseadvances and to encourage the teaching of new courses. TAM will publish textbooks suitable for use in advanced undergraduate and beginning graduate courses, and will complement the Applied Mathe- matical Sciences (AMS) series, which will focus on advanced textbooks and research-level monographs. Pasadena, California J.E. Marsden Providence, Rhode Island L. Sirovich College Park, Maryland S.S. Antman This page intentionally left blank Contents The starred sections are self-contained and may be omitted at a first reading. Series Preface ................................................. v 1 Introduction............................................... 1 2 The Equations of Inviscid Compressible Flow.............. 5 2.1 The Field Equations ..................................... 5 2.2 Initial and Boundary Conditions .......................... 13 2.3 Vorticity and Irrotationality .............................. 14 2.3.1 Homentropic Flow................................. 14 2.3.2 Incompressible Flow ............................... 17 Exercises ................................................... 18 3 Models for Linear Wave Propagation ...................... 21 3.1 Acoustics............................................... 21 3.2 Surface Gravity Waves in Incompressible Flow .............. 24 3.3 Inertial Waves .......................................... 26 3.4 Waves in Rotating Incompressible Flows.................... 29 3.5 Isotropic Electromagnetic and Elastic Waves ................ 30 Exercises ................................................... 33 4 Theories for Linear Waves ................................. 41 4.1 Wave Equations and Hyperbolicity ........................ 41 4.2 Fourier Series, Eigenvalues, and Resonance ................. 43 4.3 Fourier Integrals and the Method of Stationary Phase........ 47 4.4 *Dispersion and Group Velocity ........................... 52 4.4.1 Dispersion Relations ............................... 52 4.4.2 Other Approaches to Group Velocity................. 55 4.5 The Frequency Domain .................................. 57 4.5.1 Homogeneous Media ............................... 57 4.5.2 Scattering Problems in Homogeneous Media .......... 59 viii Contents 4.5.3 Inhomogeneous Media ............................. 62 4.6 Stationary Waves........................................ 64 4.6.1 Stationary Surface Waves on a Running Stream ....... 65 4.6.2 Steady Flow in Slender Nozzles ..................... 66 4.6.3 Compressible Flow past Thin Wings ................. 68 4.6.4 Compressible Flow past Slender Bodies .............. 73 4.7 High-frequency Waves.................................... 75 4.7.1 The Eikonal Equation.............................. 75 4.7.2 *Ray Theory ..................................... 77 4.8 *Dimensionality and the Wave Equation.................... 81 Exercises ................................................... 84 5 Nonlinear Waves in Fluids................................. 99 5.1 Introduction ............................................ 99 5.2 Models for Nonlinear Waves ..............................101 5.2.1 One-dimensional Unsteady Gasdynamics .............101 5.2.2 Two-dimensional Steady Homentropic Gasdynamics ...102 5.2.3 Shallow Water Theory .............................104 5.2.4 *Nonlinearity and Dispersion .......................106 5.3 Smooth Solutions for Nonlinear Waves .....................114 5.3.1 The Piston Problem for One-dimensional Unsteady Gasdynamics .....................................114 5.3.2 Prandtl–Meyer Flow ...............................117 5.3.3 The Dam Break Problem...........................120 5.4 *The Hodograph Transformation ..........................121 Exercises ...................................................123 6 Shock Waves ..............................................135 6.1 Discontinuous Solutions ..................................135 6.1.1 Introduction to Weak Solutions .....................136 6.1.2 Rankine–Hugoniot Shock Conditions.................142 6.1.3 Shocks in Two-dimensional Steady Flow..............144 6.1.4 Jump Conditions in Shallow Water ..................150 6.2 Other Flows involving Shock Waves........................153 6.2.1 Shock Tubes......................................153 6.2.2 Oblique Shock Interactions .........................154 6.2.3 Steady Quasi-one-dimensional Gas Flow..............157 6.2.4 Shock Waves with Chemical Reactions ...............159 6.2.5 Open Channel Flow ...............................160 6.3 *Further Limitations of Linearized Gasdynamics.............162 6.3.1 Transonic Flow ...................................162 6.3.2 The Far Field for Flow past a Thin Wing.............163 6.3.3 Non-equilibrium Effects ............................165 6.3.4 Hypersonic Flow ..................................166 Exercises ...................................................170 Contents ix 7 Epilogue...................................................181 References.....................................................183 Index..........................................................185