Offshore Structure Hydrodynamics (Cambridge Ocean Technology Series)

444 Pages·2023·22.84 MB·English

by  Bernard Molin

OffshoreStructureHydrodynamics
NewlyupdatedandtranslatedintoEnglishforthefirsttime,thisstandalonehandbook
perfectlycombinesbackgroundandtheorywithreal-worldexperiments.Allkeytop-
icsarecovered,includingenvironmentalconditions,wavetheories,hydrostatics,and
wave and current loads, with emphasis on nonlinear wave–body interaction. Focus
is given to model testing, an important component in the design of offshore struc-
tures. Recent results on the hydrodynamics of perforated structures, moonpool and
gap resonance, and third-order interaction effects have been added to this updated
version.
Based on practical experience from multiple industry collaborations, combined
withlecturesthathavebeenhonedandimprovedovermorethan30years,thepeda-
gogical, real-world approach in this book makes it an ideal companion for graduate
studentsandresearchersaswellasoceanengineers.
Bernard Molin is Emeritus Professor at Ecole Centrale Marseille. He has published
over 150 research papers, and in 2018 he received a Lifetime Achievement Award
fromtheOcean,OffshoreandArcticEngineeringDivisionofASME.
Published online by Cambridge University Press
CambridgeOceanTechnologySeries
1. O.Faltinsen:SeaLoadsonShipsandOffshoreStructures
2. RoyBurcherandLouisJ.Rydill:ConceptsinSubmarineDesign
3. JohnP.BreslinandPoulAnderson:HydrodynamicsofShipPropellers
4. R.A.ShenoiandJ.F.Wellicome(eds):CompositeMaterials
inMaritimeStructuresVolI
5. R.A.ShenoiandJ.F.Wellicome(eds):CompositeMaterials
inMaritimeStructuresVolII
6. MichelK.Ochi:OceanWaves:TheStochasticApproach
7. Dong-ShengJeng:MechanicsofWave-Seabed-StructureInteractions:
Modelling,ProcessesandApplications
8. JohannesFalnesandAdiKurniawan:OceanWavesandOscillatingSystems:
LinearInteractionsIncludingWave-EnergyExtraction
9. JeomKeePaik:Ship-ShapedOffshoreInstallations:
Design,Construction,Operation,HealthcareandDecommissioning
10. BernardMolin:OffshoreStructureHydrodynamics
Published online by Cambridge University Press
Offshore Structure
Hydrodynamics
BERNARD MOLIN
EcoleCentraleMarseille
Published online by Cambridge University Press
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www.cambridge.org
Informationonthistitle:www.cambridge.org/9781009198042
DOI:10.1017/9781009198059
©BernardMolin2023
Thispublicationisincopyright.Subjecttostatutoryexception
andtotheprovisionsofrelevantcollectivelicensingagreements,
noreproductionofanypartmaytakeplacewithoutthewritten
permissionofCambridgeUniversityPress.
Firstpublished2023
AcataloguerecordforthispublicationisavailablefromtheBritishLibrary.
LibraryofCongressCataloging-in-PublicationData
Names:Molin,Bernard,author.
Title:Offshorestructurehydrodynamics/BernardMolin.
Othertitles:Hydrodynamiquedesstructuresoffshore.English
Description:Cambridge;NewYork,NY:CambridgeUniversityPress,2023.|
Series:Cambridgeoceantechnologyseries;10|Translationof:
Hydrodynamiquedesstructuresoffshore.|Includesbibliographical
referencesandindex.
Identifiers:LCCN2022026349|ISBN9781009198042(hardback)|
ISBN9781009198059(ebook)
Subjects:LCSH:Offshorestructures–Hydrodynamics.|Offshoreoilwell
drilling.
Classification:LCCTC1665.M652023|DDC627/.98–dc23/eng/20221012
LCrecordavailableathttps://lccn.loc.gov/2022026349
ISBN978-1-009-19804-2Hardback
CambridgeUniversityPresshasnoresponsibilityforthepersistenceoraccuracyof
URLsforexternalorthird-partyinternetwebsitesreferredtointhispublication
anddoesnotguaranteethatanycontentonsuchwebsitesis,orwillremain,
accurateorappropriate.
Published online by Cambridge University Press
Contents
Preface pagexiii
Acknowledgments xiv
ListofSymbols xv
ListofAbbreviations xviii
1 Introduction 1
1.1 ClassificationofOffshoreStructures 5
1.1.1 LargeorSmallBodies 5
1.1.2 TypesofLoadingsandResponses 11
1.2 BookOutline 16
1.3 References 18
2 EnvironmentalConditions 19
2.1 Waves 19
2.1.1 TheConceptofSeaState 19
2.1.2 Wave-by-WaveAnalysis 20
2.1.3 SpectralAnalysis 21
2.1.4 Short-TermStatistics 22
2.1.5 SomeUsualSpectra 33
2.1.6 Long-TermStatistics 37
2.2 Wind 39
2.2.1 VariationoftheMeanWindVelocitywithHeight
andAveragingTime 41
2.2.2 WindSpectra 42
2.2.3 Squalls 44
2.3 Current 44
2.4 InternalWaves 44
2.5 MarineGrowthandCorrosion 46
2.6 References 48
3 WaveTheories 49
3.1 Introduction 49
3.2 GeneralEquations 50
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vi Contents
3.3 First-OrderWaveTheory 52
3.3.1 RegularWaves(Airy) 52
3.3.2 IrregularWaves 61
3.3.3 HowGoodIstheFirst-OrderApproximation? 62
3.3.4 StretchingModels 63
3.4 Second-OrderofApproximation 66
3.4.1 RegularWaves(StokesOrder2) 67
3.4.2 BichromaticSeas 68
3.4.3 IrregularSeas 71
3.5 Third-OrderofApproximation 73
3.5.1 RegularWaves(StokesOrder3) 74
3.5.2 BichromaticSeas 76
3.5.3 MultichromaticSeas 78
3.6 RegularWaveTheoriestoOrderN 79
3.6.1 TheStreamFunctionMethod 79
3.6.2 Fifth-OrderStokesTheory 81
3.7 NonlinearWaveEvolutionandWaveInstabilities 83
3.7.1 TheNonlinearSchrödingerEquation 83
3.7.2 TheBenjamin–FeirInstability 85
3.8 References 91
4 WaveandCurrentLoadsonSlenderBodies 93
4.1 PotentialFlowTheory 94
4.1.1 FixedCylinderinUniformFlow 94
4.1.2 MovingCylinderinaFluidatRest 95
4.1.3 Generalization 95
4.2 CircularCylinderinSteadyFlow 96
4.2.1 InclinedCylinders 99
4.2.2 EffectofRoughness 99
4.2.3 NoncircularCylinders 101
4.2.4 Three-DimensionalEffects 102
4.2.5 TheLiftForce 103
4.2.6 ProximityEffects 106
4.2.7 CylinderNexttotheSeabed 107
4.3 CylinderinSinusoidalFlow:TheMorisonFormula 107
4.3.1 WaveLoadonaVerticalPile 112
4.3.2 DragCoefficientatLowK Values 113
C
4.3.3 CylinderNexttotheSeaFloorinSinusoidalFlow 116
4.3.4 CylinderinOrbitalFlow 117
4.4 CircularCylinderinSteadyPlusOscillatoryFlow 118
4.4.1 In-LineCase 118
4.4.2 On-BottomStabilityofPipelinesandWakeModels 120
4.4.3 PerpendicularCase 122
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Contents vii
4.5 GeneralizedMorisonFormula 127
4.6 References 129
5 Flow-InducedInstabilities 132
5.1 Vortex-InducedVibrations 132
5.1.1 CalculatingtheVIVAmplitude 136
5.1.2 WakeOscillatorModels 138
5.1.3 VIVResponseofCablesandRisers 139
5.1.4 MitigationofVIVs 142
5.1.5 VIVsinOscillatoryFlow 144
5.1.6 In-lineVIVs 146
5.2 GallopingandFlutter 147
5.2.1 Galloping 147
5.2.2 FlutterInstabilityofaFlap 151
5.3 WakeInstabilities 152
5.4 References 156
6 LargeBodies:LinearTheory 158
6.1 Introduction 158
6.2 LinearResponseinRegularWaves 161
6.3 TheDiffraction-RadiationProblem 163
6.3.1 Haskind-HanaokaTheorem 165
6.4 MethodsofResolution 166
6.4.1 AnalyticalMethods 166
6.4.2 MatchedEigenfunctionExpansions 177
6.4.3 NumericalMethodsofResolution 179
6.4.4 ApproximateMethods 181
6.5 LoadsandResponseinIrregularSeas 184
6.6 TimeDomainResolutionoftheEquationsofMotion 186
6.7 MultipleorDeformableBodies 187
6.8 ValidityandLimitationsOfLinearTheory 188
6.8.1 WaveLoadsonFixedBodies 189
6.8.2 WaveResponseofFloatingBodies 189
6.8.3 FreeSurfaceElevations 196
6.9 RecoveryofWaveEnergy 197
6.9.1 ReversedPistonWavemaker 199
6.9.2 Wave-EnergyExtractionbyThree-Dimensional
AxisymmetricBodies 200
6.10 SloshinginTanks 202
6.11 CouplingbetweenSloshingandSea-Keeping 206
6.12 MoonpoolandGapResonances 209
6.12.1 PistonModeinMoonpoolswithVerticalWalls 209
6.12.2 PistonModeinMoonpoolswithSlowly-VaryingCross-Section 211
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viii Contents
6.12.3 SloshingModesinMoonpools 212
6.12.4 SloshingModesinGaps 213
6.12.5 ResonantModesinFiniteDepth 215
6.12.6 DampingofMoonpoolandGapResonance 215
6.13 References 216
7 LargeBodies:Second-OrderEffects 219
7.1 Introduction 219
7.2 DriftForcesinRegularWaves 220
7.2.1 MeanWaveLoadsUponaVerticalWall 220
7.2.2 Bottom-MountedVerticalCylinder 222
7.2.3 GeneralCase 224
7.2.4 EffectofCurrent 230
7.3 DoubleFrequencyLoadsinRegularWaves 234
7.4 Second-OrderLoadsinBichromaticSeas 240
7.4.1 SumFrequencySecond-OrderLoads 241
7.4.2 DifferenceFrequencySecond-OrderLoads 241
7.5 Rainey’sEquations 246
7.5.1 Second-OrderLoadsonaFixedBottom-Mounted
VerticalCylinder 248
7.5.2 WaveDriftForceonaTruncatedVerticalColumnFreetoHeave 249
7.5.3 Second-OrderVerticalLoadsonaSubmergedCircularCylinder 254
7.6 Second-OrderLoadsinIrregularWaves 254
7.7 MooringBehavior 256
7.7.1 MeanWave,Current,andWindLoads 257
7.7.2 Slow-DriftMotion 259
7.7.3 WaveDriftDamping 259
7.7.4 DampingDuetotheMooringLines 262
7.7.5 ViscousDampingattheHull 265
7.7.6 RelativeImportanceoftheDifferentDampingComponents 271
7.8 TimeDomainSimulationofSlow-DriftMotion 274
7.9 Low-FrequencyMotionsinHeave,Roll,andPitch 280
7.10 High-FrequencySecond-OrderResponse(Springing) 282
7.11 References 283
8 LargeBodies:OtherNonlinearEffects 287
8.1 Higher-OrderDiffractionLoads 287
8.1.1 Third-OrderDiffractionTheory 290
8.1.2 NumericalWaveTanks 291
8.1.3 SimplifiedFormulationsoftheRingingLoads 295
8.2 Third-OrderWave−FrequencyEffects 297
8.3 ParametricInstabilities 301
8.4 HydrodynamicImpactandWaterEntry 303
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Contents ix
8.4.1 WagnerTheory 304
8.4.2 LocalPressures 308
8.4.3 MoreElaborateModels 311
8.4.4 WaterExit 313
8.4.5 WaveImpacts 314
8.4.6 WaterEntryofThree-DimensionalBodies 316
8.5 HydrodynamicsofPerforatedStructures 316
8.5.1 AModelCase:TheTwo-DimensionalCircularCylinder 319
8.5.2 HydrodynamicCoefficientsforPlatesandDisks 323
8.5.3 WaterEntryofPerforatedBodies 325
8.5.4 IntroductionofInertiaEffects 325
8.6 References 327
9 ModelTesting 332
9.1 Introduction 332
9.2 ModelingPrinciplesandScaleEffects 332
9.2.1 MainPrinciples 332
9.2.2 ScaleEffects 334
9.2.3 ChoosingtheScale 336
9.3 ExperimentalFacilities 337
9.4 WaveGenerationandAbsorption 338
9.4.1 TypesofWavemakers 338
9.4.2 WaveAbsorbers 342
9.5 Wave-RelatedParasiticPhenomena 345
9.5.1 NearFieldoftheWavemakers 346
9.5.2 ModulationoftheWaveFront 346
9.5.3 Benjamin–FeirInstability 347
9.5.4 ReturnCurrent 348
9.5.5 FreeHarmonics 348
9.5.6 NaturalModes 349
9.5.7 Seiching 350
9.5.8 ReflectionsandSidewallEffects 352
9.6 TypesofWavesandGenerationTechniques 354
9.6.1 RegularWaves 354
9.6.2 IrregularWaves 354
9.6.3 WavePackets 356
9.7 CurrentGeneration 357
9.7.1 Towing 357
9.7.2 GlobalCirculation 357
9.7.3 LocalGeneration 358
9.7.4 Current-InducedModificationsoftheWave
Field 358
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x Contents
9.8 Wind 359
9.9 Sensors 359
9.9.1 FreeSurfaceElevation 359
9.9.2 ModelResponse 360
9.9.3 OtherSensors 361
9.10 ExploitationoftheMeasurements 362
9.10.1 RegularWaveTests 363
9.10.2 TestsinIrregularWaves 365
9.11 SpecificationofModelTests 367
9.11.1 WaveCalibrationTests 367
9.11.2 DecayTests 367
9.11.3 TestsinRegularWaves 368
9.11.4 TestsinBichromaticWaves 368
9.11.5 TestsinIrregularWaves 369
9.11.6 OtherTests 369
9.12 References 370
AppendixA:IntroductiontoPotentialFlowTheory 373
A.1 Introduction 373
A.2 TheNavier−StokesEquations 375
A.3 PotentialFlowTheory 377
A.4 SomeProblemsSolvedWithintheFrameofPotentialFlowTheory 378
A.4.1 UniformFlowuponaCircularCylinder 378
A.4.2 AcceleratedCylinderinaFluidatRest 380
A.4.3 MovingCylinderinanAcceleratedFluid 381
A.4.4 WaveGenerationbyaPistonTypeWavemaker 381
A.5 Reference 388
AppendixB:Hydrostatics 389
B.1 FullySubmergedBody 389
B.1.1 Stability 391
B.2 BodiesPiercingtheFreeSurface 392
B.2.1 StabilityCurves 392
B.2.2 LinearizedHydrostatics 394
B.2.3 Second-OrderHydrostatics 400
AppendixC:DampedMassSpringSystem 402
C.1 CasewithoutExcitation 402
C.2 ResponseunderHarmonicExcitation 403
C.3 ResponseunderRandomExcitation 405
C.4 MassSpringSystemwithQuadraticDamping 405
C.4.1 HarmonicExcitation 406
C.4.2 RandomExcitation 406
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