Preface ........................................................ xi
1 Introduction ................................................. 1
1.1 Classes of offshore structures .......................... 3
2 Review of the fundamental equations and concepts ............. 7
2.1 Equations of motion ..................................... 7
2.2 Rotational and irrotational flows ....................... 9
2.3 Velocity potential ..................................... 11
2.4 Euler's equations and their integration ................ 13
2.5 Stream function ........................................ 15
2.6 Basic inviscid flows ................................... 16
2.7 Force on a circular cylinder in unseparated inviscid
flow ................................................... 17
2.8 Slow motion of a spherical pendulum in viscous flow .... 20
2.9 Added mass or added inertia ............................ 22
2.10 An example of the role of the added inertia ............ 30
2.11 Forces on bodies in separated unsteady flow ............ 31
2.12 Kinetic energy and its relation to added mass .......... 33
3 Separation and time-dependent flows ......................... 39
3.1 Introduction and key concepts .......................... 39
3.2 Consequences of separation ............................. 42
3.3 Body and separation .................................... 47
3.4 Strouhal number ........................................ 52
3.5 Near wake and principal difficulties of analysis ....... 56
3.6 Lift or transverse force ............................... 58
3.7 Free-stream turbulence and roughness effects ........... 58
3.8 Impulsively started flows .............................. 64
3.8.1 Introductory comments ........................... 64
3.8.2 Representative impulsively started flows ........ 65
3.9 Sinusoidally oscillating flow .......................... 69
3.9.1 Introduction .................................... 69
3.9.2 Fourier-averaged drag and inertia coefficients .. 75
3.9.3 Experimental studies on Cd and Cm ............... 76
3.9.4 Transverse force and the Strouhal number ........ 85
3.9.5 Roughness effects on Cd, Cm, CL, and St in SOF .. 90
3.9.6 A critical assessment of the Morison equation ... 95
3.9.7 Oscillatory plus mean flow or the in-line
oscillations of a cylinder in steady flow ....... 98
3.9.8 Forced oscillations of a cylinder in a trough .. 104
3.9.9 Oscillatory flow in a smaller U-shaped water
tunnel ......................................... 107
4 Waves and wave-structure interactions ...................... 109
4.1 Surface gravity waves ................................. 109
4.1.1 Linear wave theory ............................. 110
4.1.2 Higher-order wave theories ..................... 115
4.1.3 Character of the forces predicted .............. 117
4.1.4 Random waves ................................... 119
4.1.5 Representative frequency spectra ............... 121
4.2 Wave-structure interaction ............................ 122
4.2.1 Principal factors of analysis and design ....... 123
4.2.2 Design wave and force characterization ......... 125
4.2.3 Force-transfer coefficients .................... 127
4.2.4 A brief summary of the literature giving
explicit Cd and Cm values ...................... 135
4.2.5 Suggested values for force-transfer
coefficients ................................... 138
4.2.6 Effects of orbital motion, coexisting
current, pile orientation, interference, and
wall proximity ................................. 139
4.2.7 Pipe lines and wall-proximity effects .......... 155
4.2.8 Wave impact loads .............................. 166
5 Wave forces on large bodies ................................ 172
5.1 Introduction .......................................... 172
5.2 The case of linear diffraction ........................ 175
5.3 Froude-Krylov force ................................... 176
5.4 The case of a circular cylinder ....................... 177
5.5 Higher-order wave diffraction and the force acting
on a vertical cylinder ................................ 181
5.6 Closing remarks ....................................... 184
6 Vortex-induced vibrations .................................. 186
6.1 Key concepts .......................................... 186
6.1.1 Nomenclature .................................... 190
6.2 Introduction .......................................... 192
6.3 Added mass, numerical simulations, and VIV ............ 203
6.4 Governing and influencing parameters .................. 204
6.4.1 Parameter space ................................ 204
6.4.2 Uncertainties .................................. 207
6.4.3 Mass and structural damping .................... 208
6.4.4 ƒvac, ƒcom, and added mass ..................... 209
6.5 Linearized equations of self-excited motion ........... 211
6.6 Unsteady force decomposition .......................... 213
6.6.1 Lighthill's force decomposition ................ 215
6.7 Limitations of forced and free vibrations ............. 217
6.7.1 General discussion ............................. 217
6.7.2 Amplitude and phase modulations ................ 219
6.8 Experiments with forced oscillations .................. 223
6.8.1 A brief summary of the existing contributions .. 223
6.8.2 Detailed discussion of more recent
experiments .................................... 227
6.9 The wake and the VIV .................................. 232
6.10 Self-excited vibrations ............................... 240
6.11 Discussion of facts and numerical models .............. 250
6.12 Suppression devices ................................... 252
6.13 Evolution of numerical models ......................... 255
6.14 Experiments with advanced models ...................... 262
7 Hydrodynamic damping ....................................... 265
7.1 Key concepts .......................................... 265
7.2 Introduction .......................................... 265
7.3 Elements of damping ................................... 267
7.3.1 Stokes canonical solutions ..................... 268
7.4 Previous investigations ............................... 270
7.5 Representative data ................................... 272
7.5.1 Solid cylinders ................................ 272
7.5.2 Perforated cylinders ........................... 274
7.5.3 Three-dimensional instabilities ................ 275
7.5.4 Closing remarks ................................ 280
References .................................................... 285
Index ......................................................... 321
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