TheCurrentStatusofCFDinITTC 2:Maneuvering&Seakeeping 2: Maneuvering &Seakeeping

FrederickStern Frederick SternIIHRHydroscience&Engineering TheUniversityofIowa IowaCity,IA52242USA1

Tableofcontents1. CFDbasedmaneuveringmethodsinSIMMAN2008 1 CFD based maneuvering methods in SIMMAN 2008 1.1Overview 1.1 Overview 1.2VerificationandValidation(V&V) 1.3Forcesandmomentcoefficients 1.4Maneuveringderivatives 1.5PIVcomparisons p 1.6Trajectories 2. LatestapplicationofCFDtoseakeeping 3. Computationaltowingtankapproach2

CFDbasedmaneuveringpredictionmethod CFD based maneuvering prediction methodNoSimulation SystemBasedManeuveringSimulationModeltesting

CFDBasedManeuvering SimulationComputationalmethods

DatabaseMethod Trajectory/HydrodynamicDerivatives FullscaleTrials

CaptiveModelTests FreeModelTests System Identification

Inviscid methods

RANS methods

Mathematicalmodel

ManeuveringDerivatives, HydrodynamicCoefficients

Equationofmotion Ship Ship specification

Trajectories

Derivedmaneuveringparameters(advance,transfer,overshootsetc.) Criteria C it i Maneuverability:Acceptableornot

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1.CFDbasedmaneuveringmethodsinSIMMAN2008 1 CFD based maneuvering methods in SIMMAN20081.1Overview

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1.CFDbasedmaneuveringmethodsinSIMMAN2008 1 CFD based maneuvering methods in SIMMAN2008 1.2VerificationandValidation:5415,IIHR,CFDShipIowa Staticdrift(Fr=0.28,=10) Verification V ifi tiUI (%S1) |g21/S1|100 Rg Without X'T 0.26 2.82 0.70 walls Y'T 0.015 0.19 3.01 r=2 N'T 0.020 0.97 1.06 Finemediumcoarse:19M6.9M2.4M pg Cg Convergence Ug (%S1) OC 2.02 OD OD

Validation|E| (%D) UV (%D) UD (%D) USN (%D) Without Without X'T 7.68 7 68 4.20 4 20 3.6 36 2.17 2 17 walls Y'T 13.44 5.4 r=2 N'T 0.98 2.6 Slowlydampedoscillation 4shiplengthsfortransient 8shiplengthsforstatisticalconvergence DifficulttoachievemonotonicconvergenceinY'T andN'T X'T isnotvalidated.5

Pureyaw(Fr=0.28,r'=0.3) Verification:FourierSeriesdecomposedquantitiesUI ( ) | k21| ( ) Rk (%) | |(%) pk Ck Convergence Uk ( ) (%) X'0 0.51 6.16 0.85 0.46 0.18 MC 92.43 X'2 10.26 18.73 0.39 OC 24.21 Grid Y'1 0.32 7.61 2.52 MD (r=2) Y'3 29.36 17.16 1.93 OD N'1 0.16 1.17 5.04 OD N'3 8.74 71.57 25.32 MD X'0 0.49 1.76 0.18 2.50 1.55 MC 2.77 X X'2 0 95 0.95 31.96 31 96 0.62 0.69 0.20 0 62 0 69 0 20 MC 135.04 135 04 Timestep Y'1 0.21 8.64 0.49 1.04 0.35 MC 18.73 (r=2) Y'3 5.63 10.47 1.71 MD N N'1 0 14 0.14 3.96 3 96 0.47 1.09 0.37 0 47 1 09 0 37 MC 7.96 7 96 N'3 5.69 0.92 0.04 4.80 8.97 MC Withwalls,5.5M1.58M0.56M Timestepconvergenceeasiertoachievethangridconvergence NeedmarchingFSanalysisformoreaccurateUI estimation6

%S1

Grid:Withoutwalls,4.5M1.59M0.56M,r=2 Timestep:r=2

Verification:Timeaveragedquantities UG(%D) UT(%D) USN (%D) X'T 1) 5.50 2.60 6.08 Y'T 2) 1.00 6.89 7.00 N N'T2) 0.20 0 20 7.74 7 74 7.74 7 74

Validation:Timeaveragedquantities|E|(%D) UV (%D) UD (%D) USN (%D) X ) X'T1) 18.41 18 41 8.94 8 94 6.56 6 56 6.08 6 08 Y'T2) 10.21 23.45 22.38 7.00 N'T2) 2.70 7.90 1.57 7.74 1)%D,2)%DdynamicrangeofYT NT' 1) %D 2) % D d i f Y orN UG(%D) UT (%D) 5.50 5 50 2.60 2 60 1.00 6.89 0.20 7.74

Friction tendstomonotonicallyconvergeover1PMMperiodthanpressurewith lower USN. Y'T andN'T arevalidated.NeedtocheckUD inY'T.7

1.CFDbasedmaneuveringmethodsinSIMMAN2008 1 CFD based maneuvering methods in SIMMAN20081.3Forcesandmomentcoefficients:KVLCC1(Fr=0.142)

Puresway(corr=4.9)

Pureyaw(r'=0.3) y ( )Puresway Pure sway OverpredictioninX' GoodpredictioninY' andN and N' Pureyaw Largephaseand amplitudedifference li d diff inX' Minorphaseleadin Y'comparedtoEFD GoodpredictioninN'

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1.CFDbasedmaneuveringmethodsinSIMMAN2008 1 CFD based maneuvering methods in SIMMAN20081.3Forcesandmomentcoefficients:KCS(Fr=0.202)

Puresway( Pure sway (corr=8) 8)

Pureyaw(r 0.4) Pure yaw (r'=0.4)

Puresway Overprediction in X' Over predictioninX GoodpredictioninY'andN' Pureyaw High frequency oscillation Highfrequencyoscillation forX' inCFD andY' inEFD MinorphaseleadinN' comparedtoEFD compared to EFD

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1.CFDbasedmaneuveringmethodsinSIMMAN2008 1 CFD based maneuvering methods in SIMMAN2008 1.3Forcesandmomentcoefficients:5415,staticdrift(Fr=0.28,=10),IIHR,CFDShipIowaCoefficient X' E(%D) E (%D) Y' E(%D) N' E(%D) Coefficient X' E(%D) Y' E(%D) N' E(%D)10

D 0.0195 0.05795 0.02845 0 02845 D 0.0195 0.05795 0 05795 0.02845

Convectionscheme/Turbulence1) FD2BKW 0.02094 7.4% 0.06576 13.5% 0.02875 0 02875 1.05% TVD2SARS 0.02025 3.8% 0.06408 10.6% 0.0285 0 0285 0.17% FD4hBKW 0.02074 6.4% 0.06566 13.3% 0.02872 0 02872 0.95%

URANS,FD2 BKW DES,FD4h BKW URANS, FD2BKW2) DES, FD4hBKW2) 0.0210 0.02032 7.7% 4.21% 0.06574 0 06574 13.4% 0.02873 0.98% 0.0665 0 0665 13.2% 0.0291 2.28%

TVD2SARS providesthe bestresults consistent toKVLCC2application DESonlyimprovesX'. Movie:URANSvs DES

Overall Leewardbow Stern

#ofgridpoints:1)2.4M,2)19M

Staticdrift(TVD2SARS,2.4Mgridpoints) St ti d ift (TVD2S ARS 2 4M id i t )

F ForcesandmomentcoefficientsfollowtheEFDtrend. d ffi i f ll h EFD d Significantincreasein|E|at1211

turb.vs.laminar TVD2SARS Laminar X 0.0166 0.01566 0.00845 0deg E(%D) 5.7% 49.1% X X 0.0195 0.0195 0.02025 0.02025 0.0125 0.0125 E(%D) 3.8% 35.9% Y 0.05795 0.06408 0.06419 10deg 10 deg E(%D) E (%D) 10.6% 10 6% 10.8% 10 8% N 0.02845 0.0285 0.0300 E(%D) 0.17% 5.4% ( ) X 0.0287 0.0366 0.0246 E(%D) 27.5% 14.3% Y 0 1529 0.1902 0 1902 0 1550 0.1529 0.1550 20deg E(%D) 24.4% 1.4% N 0.0594 0.0690 0.0607 E(%D) 16.2% 2.2% #ofgridpoints=2.4M,Fr=0.28 beta Coef. D12

Laminarsolution givesbetterresults atlargerdrift angles Expectthe contributionof transition turbulencemodel

1.CFDbasedmaneuveringmethodsinSIMMAN2008 1 CFD based maneuvering methods in SIMMAN20081.3Forcesandmomentcoefficients:5415(Fr=0.28)

Puresway(corr=10) y ( )

Pureyaw(r'=0.3) y ( )Puresway Pure sway OscillationinX' apparentinCFD Good prediction in Y' GoodpredictioninY andN':consistentto KVLCC/KCS Pureyaw Pure yaw UnderpredictioninX' inCFD Minor phase lag in Y' MinorphaselaginY comparedtoEFD

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1.CFDbasedmaneuveringmethodsinSIMMAN2008 1 CFD based maneuvering methods in SIMMAN20081.4Maneuveringderivatives:KVLCC2

KVLCC2,shallowwater(Southampton,CFX),Fr=0.064

Shallowwatereffectmakesestimationof h ll ff k f linearderivativelessaccurate. Linear derivatives are wellpredicted, except Linearderivativesarewell predicted,except Y' byPARANNASOS. KVLCC2M,deepwater (Toxopesu 2008,PARANASSOS),Fr=0.0,ref.JMST , p ( p , ), ,

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1.CFDbasedmaneuveringmethodsinSIMMAN2008 1 CFD based maneuvering methods in SIMMAN20081.4Maneuveringderivatives:5415(Fr=0.28),IIHR,CFDShipIowa

Linearderivativespredictedwell within10%Derror. Nonlinear and acceleration Non linear andacceleration dependent derivativesneedmore accuracy.

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1.CFDbasedmaneuveringmethodsinSIMMAN2008 1 CFD based maneuvering methods in SIMMAN20081.5PIVcomparisons:5415puresway(Fr=0.28)

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1.CFDbasedmaneuveringmethodsinSIMMAN2008 1 CFD based maneuvering methods in SIMMAN20081.5PIVcomparisons:5415pureyaw(Fr=0.28),IIHR,CFDShipIowa

X=0.135: U V W x TKE

X=0.535: U V W x TKE

X=0.935: U U V W x TKE

OveralltrendsarewellpredictedbetweenCFDandEFD. Apparentmomentum/TKEdefectatvortexcoreincertainphasesandcross A t t /TKE d f t t t i t i h d planescomparedtotheEFDdata Possiblereasonsare:gridresolution,momentumandturbulence convectionscheme,isotropic turbulencemodel17

Advance [LPP] P

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Turningcircle(=35)MARIN (SURSIM SB RANS) ( ) HSVA (NEPIII) IIHR (CFD)

STBD Hea ading angle [deg]

1.CFDbasedmaneuveringmethodsinSIMMAN2008 1 CFD based maneuvering methods in SIMMAN2008 20/20 zigzag maneuver 1.6Trajectories:KVLCC160 40

4

EFD

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0 0 100 200 300 400 500 600 700 800 900 1000

Time [sec]-20

3

-40

PORT

2

-6060

MARIN (SURSIM SB RANS) HSVA (NEPIII)

1

STBD

MARIN (SURSIM SB RANS) HSVA (NEPIII) IIHR (CFD)

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0Heading angle [d deg]20

-5

-4

-3

-2

-1

0

Transfer [LPP]

0 0 100 200 300 400 500 600 700 800 900 1000

MOVIE (Turningcircle) byIIHR:CFDShipIowa by IIHR: CFDShipIowa

Time [sec]-20

-40

PORT

HSVA:Verywellpredictedtrajectoryinturningcircle IIHR,MARIN:Advanceandtacticaldiameterunderpredictedinturningcircle IIHR MARIN: Advance and tactical diameter under predicted in turning circle Zigzag:Phaseandamplitudedifferenceafterthe1stexecute(MARIN,IIHR)and 18 2ndexecute(HSVA) 18

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1.CFDbasedmaneuveringmethodsinSIMMAN20081.6Trajectories:5415 1 6 Trajectories: 5415 Turningcircle(=35)

20/20 zigzag maneuver

MOVIE (Turning circle in waves) (Turningcircleinwaves) byIIHR:CFDShipIowa

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2.LatestapplicationofCFDtoseakeeping:5512forwardspeeddiffraction 2 Latest application of CFD to seakeeping: 5512 forward speed diffraction Fr=0.41,l/L=1.5,ak=0.025,70Mgridpoints. Freesurface Massivebreakingwavesatbow, Transomdetail shoulderandstern Highlyturbulenttransomflow Bowdetail Freesurfaceandturbulentstructures Verydetailunsteadyvortical structureresolvedbyDES y Turbulentstructuresdetail b l d l

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2.LatestapplicationofCFDtoseakeeping:ONRtumblehome(Freerunningtest) 2 Latest application of CFD to seakeeping: ONR tumble home (Freerunning test)CFDtestmatrix: /L 1.25 1.25 1.25 GM(m) fullscale 1.78m 2.068m 2.068m Rudderangle ( g) Limit(deg) 34.2 29.7 28

Case# 41 83 85

H/ 0.05 0.05 0.05

Fr 0.4 0.4 0.4

course(deg) 15 30 5

Phenomenon

broaching periodicmotion surfriding

EFDtestmatrix:0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0 15 0.1 0 Periodic Motion Surf Riding Broaching-to

Nominal Froud number de

/L=1.25, H/=1/20, / / / GM=2.068 m

lambda/L 1 25 l bd /L =1.25,waves teepnes s =1/20,GM=2.068 1/20 GM 2 068

lambda/L=1.25, /L 1.25, H/=1/20 GM=1 78 /L=1 25 H/ wave steepness=1/20 1.78 1/20, GM 0.5 m 0.4 periodic broach stable surf-riding

0.3

0.2

No 85 10

20

No 8330

0.1 040

No 10 41

20

30

40

autopilot course (degrees)

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Results: R lt

Broaching(#41)EFD vs CFD h ( )

Periodicmotion(#83)EFD vs CFD

Surfriding(#85)EFD vs CFD

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Conclusion: CFDiscapable ofpredictingsurfriding,periodicmotionand broaching. AphaselagbetweenCFDandEFDduetoinaccurateinitial conditionsforwavephaseandinitialsurgevelocity. Futurework: CFD simulations with correct initial conditions measured in CFDsimulationswithcorrectinitialconditionsmeasuredin experiments Trajectory willbecomparedwithexperiment.

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3.Computationaltowingtank(CTT)approach:Implementation 3 Computational towing tank (CTT) approach: Implementation Gridvelocity:Absoluteinertialearthfixedcoordinate & VG = R + r Momentumequation: Absoluteinertialearthfixedcoordinate1 2 V + (V V G ) V = ( p + Z ) + V Re t

Transformationto Noninertialshipfixedcoordinate usingVr:relativevelocitytoCV using Vr: relative velocity to CV Vr = V V G% Vr 1 2 + Vr Vr = ar ( p + z ) + Vr { Re t body force

&& & ar = R + 2 Vr + ( r ) + r24

3.Computationaltowingtankapproach:Applicationforresistanceandpropulsion 3 Computational towing tank approach: Application for resistance and propulsion FullcurveFrresistancesimulations FullcurveFrpropulsionsimulations

Med&high Fr:Anefficientandaccuratetooltopredictcurvesof resistanceandpropulsionforshipflowsusingasinglerun CTTprocedureisnotpossibleorhighlydifficultusingaphysicaltowingtank apotentialofusingtheCTTinthedesignprocess.25

3.Computationaltowingtankapproach:Deterministicwavepacket 3 Computational towing tank approach: Deterministic wave packet 20wavescomponents;3