Fundamentals of Aerodynamits

fth Edtn n SI Unt

John D. Anderson, Jr. Curator of National Air and Space Museum Smithsonian Institution and Professor Emeritus University of Maryland

M Gr ll

Snpr • tn • rr d, I • b, IA • Mdn, WI • Yr • Sn rn St. • n • Kl pr • bn • ndn • Mdrd Mx Ct • Mln • Mntrl • lh • Sl • Sdn • p • rnt rf t th fth Edtn xx .2 Appld Ardn: h Ardn Cffnt—hr Mntd nd rtn . trl t: h Illv Cntr A f rr 8 ndntl rnpl .4 trl t: Ardn Cffnt Chptr . Sr Ardn: S Intrdtr .6 rbl 8 hht . Iprtn f Ardn: trl Chapter 2 Expl Ardn: S ndntl rnpl .2 Ardn: Clftn nd rtl nd Etn 0 Objtv 2. . d Mp fr h Chptr Intrdtn nd d Mp 04 2.2 .4 S ndntl Ardn v f tr ltn 0 rbl 2.2.1 Some Vector Algebra 106 1.4.1 Units 18 2.2.2 Typical Orthogonal Coordinate Systems 107 . Ardn r nd Mnt 2.2.3 Scalar and Vector Fields 110 .6 Cntr f rr 2 2.2.4 Scalar and Vector Products 110 . nnl Anl: h nh hr 4 2.2.5 Gradient of a Scalar Field 111 .8 l Slrt 4 2.2.6 Divergence of a Vector Field 113 . ld Stt: n r 2 2.2.7 Curl of a Vector Field 114 .0 p f l 62 2.2.8 Line Integrals 114 2.2.9 Surface Integrals 115 1.10.1 Continuum Versus Free Molecule Flow 62 2.2.10 Volume Integrals 116 1.10.2 Inviscid Versus 'Viscous Flow 62 2.2.11 Relations Between Line, Surface, and Volume Integrals 117 1.10.3 Incompressible Versus Compressible Flows 64 2.2.12 Summary 117 1.10.4 Regimes 64 2. Mdl f th ld: Cntrl l nd . l: Intrdtn t ndr ld Elnt r 68 2.3.1 Finite Control Volume Approach 118

x xii Contents

2.3.2 Infinitesimal Fluid Element 3.2 Bernoulli's Equation 207 Approach 119 3.3 Incompressible Flow in a Duct: The Venturi 2.3.3 Molecular Approach 119 and Low-Speed Wind Tunnel 211 2.3.4 Physical Meaning of the Divergente 3.4 Pitot Tube: Measurement of of Velocity 120 Airspeed 224 2.3.5 Specification of the Flow Field 121 3.5 Pressure Coefficient 233 2.4 Continuity Equation 125 .6 Condition an Velocity for Incompressible 2.5 Momentum Equation 130 Flow 235 2.6 An Application of the Momentum Equation: 3.7 Governing Equation for Irrotational, of a Two-Dimensional Body 135 Incompressible Flow: Laplace's 2.6.1 Comment 144 Equation 236 2.7 Energy Equation 144 3.7.1 Infinity Boundary Conditions 239 2.8 Interim Summary 149 3.7.2 Wall Boundary Conditions 239 2.9 Substantial Derivative 150 .8 Interim Summary 240 2.10 Fundamental Equations in Terms 3.9 Uniform Flow: Our First Elementary of the Substantial Derivative 156 Flow 241 2.11 Pathlines, Streamlines, and Streaklines 3.10 Source Flow: Our Second Elementary of a Flow 158 Flow 243 2.12 Angular Velocity, Vorticity, and Strain 163 . Combination of a Uniform Flow with a 2.13 Circulation 174 Source and Sink 247 2.14 Stream Function 177 .2 Doublet Flow: Our Third Elementary 2.15 Velocity Potential 181 Flow 251 Nonlifting Flow over a Circular 2.16 Relationship Between the Stream Function . and Velocity Potential 184 Cylinder 253 2.17 How Do We Solve the Equations? 185 .4 Vortex Flow: Our Fourth Elementary Flow 262 2.17.1 Theoretical (Analytical) Solutions 185 . Lifting Flow over a Cylinder 266 2.17.2 Numerical Solutions-Computational (CFD) 187 .6 The Kutta-Joukowski Theorem and the Generation of 280 2.17.3 The Bigger Picture 194 Nonlifting Flows over Arbitrary Bodies: 2.8 Summary 194 . The Numerical Source Panel 2.19 Problems 198 Method 282 .8 Applied Aerodynamics: The Flow over a Circular Cylinder-The Real Case 292 A 2 . Historical Note: Bernoulli and Euler-The Invd, Inprbl l 20 Origins of Theoretical Fluid Dynamics 300 Chptr .20 Historical Note: d'Alembert and His ndntl f Invd, Inprbl Paradox 305 l 20 .2 Summary 306 3.1 Introduction and Road Map 204 .22 Problems 309 Cntnt x

Chptr 4 fhptr Incompressible Flow over 313 Incompressible Flow over Finite 411 4.1 Intrdtn 5.1 Intrdtn: nh nd Indd 4.2 Arfl nltr 8 r 4 4.3 Arfl Chrtrt 20 5.2 h rtx lnt, th tSvrt , 4.4 hlph f hrtl Sltn nd lhltz hr 420 fr Spd l vr Arfl: h 5.3 rndtl Cll ftnn rtx Sht 2 hr 424 4.5 h Ktt Cndtn 0 5.3.1 Elliptical Lift Distribution 430 4.5.1 Without Friction Could We Have 5.3.2 General Lift Distribution 435 Lift? 334 5.3.3 Effect of Aspect Ratio 438 4.6 Klvn Crltn hr nd th 5.3.4 Physical Significance 444 Strtn rtx 4 5.4 A rl nlnr ftnn 4.7 Cll hn Arfl hr: h Mthd 4 Str Arfl 8 5.5 h ftnSrf hr nd th rtx 4.8 h Cbrd Arfl 48 tt rl Mthd 4 4.9 h Ardn Cntr: Addtnl 5.6 Appld Ardn: h lt Cndrtn Wn 464 4.10 ftn l vr Arbtrr 5.7 trl t: nhtr nd d: h rtx nl rndtlh Erl vlpnt f rl Mthd 6 ntWn hr 46 4.11 Mdrn Spd Arfl 6 5.8 trl t: rndtlh 4.12 l: Arfl r Mn 480 4.12.1 Estimating Skin-Friction Drag: 5.9 Sr 48 Laminar Flow 372 5.10 rbl 484 4.12.2 Estimating Skin-Friction Drag: Turbulent Flow 374 Chptr 6 4.12.3 Transition 376 Three-Dimensional Incompressible 4.12.4 381 Flow 487 4.12.5 Comment 386 6.1 4.13 Appld Ardn: h l vr Intrdtn 48 n Arflh l C 8 6.2 hrnnl Sr 488 4.14 trl t: Erl Arpln 6.3 hrnnl blt 40 n nd th l f Arfl 6.4 l vr A Sphr 42 hn 8 6.4.1 Conzment an the Three-Dimensional 4.15 trl t: Ktt, , Relieving Effect 494 nd th Crltn hr 6.5 Gnrl hrnnl l: nl f ft 40 hn 4 4.16 Sr 40 6.6 Appld Ardn: h l vr 4.17 rbl 40 Sphrh l C 4 xv Cntnt

6. Appld Ardn: Arpln ft 8. Spd f Snd nd r 00 8.3.1 Comments 563 6.7.1 Airplane Lift 500 8.4 Spl r f th Enr 6.7.2 Airplane Drag 502 Etn 64 6.7.3 Application of Computational Fluid 8. Whn I A l Cprbl? 2 Dynamics for the Calculation of Lift and 8.6 Clltn f rl ShWv Drag 507 rprt 6.8 Sr 8.6.1 Comment on the Use of Tables to Solve 6. rbl 2 Compressible Flow Problems 590 8. Mrnt f lt n Cprbl l 8.7.1 Subsonic Compressible Flow 591 A Inviscid, Compressible Flow 513 8.7.2 Supersonic Flow 592 8.8 Sr 6 8. rbl Chptr Cprbl l: S rlnr Apt Chptr 9 . Intrdtn 6 Obl Sh nd Expnn Wv 60 .2 A rf v f hrdn 8 . Intrdtn 602 7.2.1 Perfect Gas 518 .2 Obl Sh ltn 608 7.2.2 Internal Energy and Enthalpy 518 . Sprn l vr Wd 7.2.3 First Law of Thermodynamics 523 nd Cn 622 7.2.4 Entropy and the Second Law of 9.3.1 A Comment on Supersonic Lift and Drag Thermodynamics 524 Coefficients 625 7.2.5 Isentropic Relations 526 .4 Sh Intrtn nd fltn 626 . fntn f Cprblt 0 . thd Sh Wv n rnt f lnt .4 Gvrnn Etn fr Invd, d 62 Cprbl l 9.5.1 Comment on the Flow Field behind a . fntn f tl (Stntn Curved Shock Wave: Entropy Gradients Cndtn and Vorticity 636 .6 S Apt f Sprn l: Sh .6 rndtlMr Expnn Wv 66 Wv 40 . ShExpnn hr: Appltn t . Sr 44 Sprn Arfl 648 .8 rbl 46 .8 A Cnt n ft nd r Cffnt 62 Chptr 8 . h nd It Wd l 62 rl Sh Wv nd ltd p 4 .0 l: ShWv ndrr Intrtn 6 8. Intrdtn 0 . trl t: Ernt MhA 8.2 h rl Sh Etn rphl Sth 6 Cntnt xv

.2 Sr 662 . Appld Ardn: h lndd . rbl 66 Wn d 4 .2 trl t: hSpd ArflErl rh nd Chptr 10 vlpnt 60 Cprbl l thrh zzl, ffr, . trl t: h Orn f h nd Wnd nnl 66 SptWn Cnpt 64 0. Intrdtn 60 .4 trl t: hrd . 0.2 Gvrnn Etn fr WhtbArhtt f th Ar l QOnnnl l 62 nd th Sprrtl Wn 0. zzl l 68 . Sr 4 10.3.1 More on Mass Flow 695 .6 rbl 6 0.4 ffr 66 Sprn Wnd nnl 68 0. Chptr 12 0.6 l: ShWv ndrr Intrtn nd nrzd Sprn l nzzl 04 2. Intrdtn 80 0. Sr 06 2.2 rvtn f th nrzd Sprn 0.8 rbl 0 rr Cffnt rl 80 2. Appltn t Sprn Arfl 84 Chptr 11 2.4 l: Sprn Arfl Sbn Cprbl l vr Arfl: r 0 nr hr 2. Sr . Intrdtn 2 2.6 rbl 4 .2 h lt tntl Etn 4 . h nrzd lt tntl Chptr Etn Intrdtn t rl hn .4 rndtlGlrt Cprblt fr nlnr Sprn l Crrtn 22 . Iprvd Cprblt . Intrdtn: hlph f Cpttnl Crrtn 2 ld n 8 .6 Crtl Mh br 28 .2 Elnt f th Mthd f Chrtrt 800 11.6.1 A Comment on the Location of Minimum Pressure (Maximum Velocity) 737 13.2.1 Internal Points 806 . rvrn Mh br: h 13.2.2 Wall Points 807 Snd rrr . Sprn zzl n 808 .8 h Ar l 4 .4 Elnt f ntffrn . h Sprrtl Arfl 4 Mthd 8 .0 C Appltn: rnn Arfl 13.4.1 Predictor Step 817 nd Wn 4 13.4.2 Corrector Step 817 xv Cntnt

. h pndnt hn: 4. Appld prn Ardn: Appltn t Sprn lnt prn Wvrdr 86 d 88 14,9.1 Viscous Optimized Waveriders 882 13.5.1 Predictor Step 822 4.0 Sr 80 13.5.2 Corrector Step 822 4. rbl 80 .6 l vr Cn 826 13.6.1 Physical Aspects of Conical Flow 827 13.6.2 Quantitative Formulation 828 A 4 13.6.3 Numerical Procedure 833 l 8 13.6.4 Physical Aspects of Supersonic Flow Over Cones 834 Chptr . Sr 8 .8 rbl 88 Intrdtn t th ndntl rnpl nd Etn f l 8 . Intrdtn 84 Chptr 4 .2 Qlttv Apt f Elnt f prn l 8 l 8 4. Intrdtn 840 . t nd hrl Cndtn 0 4.2 Qlttv Apt f prn .4 h vrSt Etn 08 l 84 . h l Enr Etn 2 4. tnn hr 84 .6 Slrt rtr 6 4.4 h ft nd r f Wn t prn . Sltn f l: A rlnr Spd: tnn lt fr t lt n 20 t Anl f Att 84 .8 Sr 2 14.4.1 Accuracy Considerations 856 . rbl 2 4. prn ShWv ltn nd Anthr t tnn hr 860 Chptr 6 4.6 Mh br Indpndn 864 A Spl C: Ctt l 2 4. prn nd Cpttnl ld n 866 6. Intrdtn 2 4.8 prn l: Ardn 6.2 Ctt l: Gnrl n 28 tn 86 6. Inprbl (Cntnt rprt 14.8.1 Aerodynamic Heating and Hypersonic Ctt l 2 Flow—the Connection 869 16.3.1 Negligible Viscous Dissipation 938 14.8.2 Blunt versus Slender Bodies in 16.3.2 Equal Wall Temperatures 939 Hypersonic Flow 871 16.3.3 Adiabatic Wall Conditions (Adiabatic 14.8.3 Aerodynamic Heating to a Wall Temperature) 941 Blunt Body 874 16.3.4 Recovery Factor 944 Cntnt xv

16.3.5 Reynolds Analogy 945 Chptr 16.3.6 Interim Summary 946 rblnt ndr r 0 6.4 Cprbl Ctt l 48 . Intrdtn 020 16.4.1 Shooting Method 950 .2 lt fr rblnt ndr r 16.4.2 Time-Dependent Finite-Difference n lt lt 020 Method 952 19.2.1 Reference Temperature Method 16.4.3 Results for Compressible Couette for Turbulent Flow 1022 Flow 956 19.2.2 The Meador-Smart Reference 16.4.4 Some Analytical Considerations 958 Temperature Method for Turbulent 6. Sr 6 Flow 1024 19.2.3 Prediction of Drag 1025 Chptr 17 . rbln Mdln 02

Intrdtn t ndr r 6 19.3.1 The Baldwin Lomax Model 1026 .4 nl Cnt 028 . Intrdtn 66 . Sr 02 .2 ndrr rprt 68 .6 rbl 00 . h ndrr Etn 4 .4 W Slv th ndrr Etn? Chptr 20 . Sr vrSt Sltn: S Expl 0 Chptr 8 20. Intrdtn 02 nr ndr r 8 20.2 h Apprh 02 20. Expl f S Sltn 0 8. Intrdtn 8 20.3.1 Flow over a Rearward-Facing Step 1033 8.2 Inprbl l vr lt lt: h l Sltn 82 20.3.2 Flow over an Airfoil 1033 8. Cprbl l vr lt lt 8 20.3.3 Flow over a Complete Airplane 1036 20.3.4 Shock-Wave/Boundary-Layer Interaction 18.3.1 A Comment on Drag Variation 1037 with Velocity 1000 h frn prtr Mthd 00 20.3.5 Flow over an Airfoil with a Protuberance 8.4 1038 18.4.1 Recent Advances: The Meador-Smart Reference Temperature Method 1004 20.4 h I f Ar fr th rdtn f Sn rtn r 040 8. Stntn nt Ardn 20. tn 00 Sr 04 8.6 ndr r vr Arbtrr d: ntffrn Sltn 0 Appndx A Intrp l rprt 04 18.6.1 Finite Difference Method 1012 8. Sr 0 Appndx 8.8 rbl 08 rl Sh rprt 0 xv Cntnt

Appndx C blrph 0 rndtlMr ntn nd Mh Indx 0 Anl 0 Appndx Stndrd Atphr 06