comparison of openfoam and fluent for … of openfoam® and fluent for steady, viscous flow at pool...

COMPARISONOFOpenFOAM®ANDFLUENTFORSTEADY,VISCOUSFLOWATPOOL8,MISSISSIPPIRIVER

IIHR–Hydroscience&EngineeringTheUniversityofIowa

OscarEduardoHernandezMurcia,MSc.

PhDGraduateStudent‐IIHR

Outline • Introduction

• Model configuration in FLUENT

• Model configuration in OpenFOAM

• Results

• Conclusions

• References

• Acknowledgments

IntroducIonCasestudy,generaldescrip2on,objec2ve

•  Loca&on:UpperMississippiriver.RoundLake

•  Mainobjec&ve:comparetheperformanceofOpenFOAMandFLUENTinarealcasestudygiventhesameconfigura&on.

IntroducIonCasestudy,eleva2ondistribu2oninmeters

IntroducIonMesh

Meshsize,Structuredgrid#Cells=325206,#faces=1020815,#Nodes=371410Not issues found when transformingFLUENTmeshtoOpenFOAMmesheventhatthemeshhasabigaspectra&o.

DomainExtents:x‐coordinate:min(m)=‐1.353054e‐001,max(m)=1.134000e+003y‐coordinate:min(m)=‐1.897500e+003,max(m)=‐6.500000e+000z‐coordinate:min(m)=1.869350e+002,max(m)=1.925366e+002VolumestaIsIcs:minimumvolume(m3):1.550512e‐002maximumvolume(m3):1.344539e+001totalvolume(m3):3.959642e+005FaceareastaIsIcs:minimumfacearea(m2):6.500244e‐003maximumfacearea(m2):6.410345e+001

ModelconfiguraIoninFLUENTGeneralparameters

1.Steadyflow2.Viscousmodel:k‐epsilon(2eqn.),standard.

3.Near‐WallFunc&ons:StandardwallFunc&ons4.K‐epsilonModelConstants:

Cmu=0.09;C1‐Epsilon=1.44,C2‐Epsilon=1.92,TKEPrandtlNumber=1,TDRPrandtlNumber=1.3.

5.Material:water‐liquid

6.Density(kg/m3)=998.27.Viscosity(kg/m‐s)=0.001003

Modelconfigura&oninFLUENT–BoundaryCondi2ons(BC)

mass‐flow‐inlet‐4

Pressure‐outlet‐8

river_bed‐5

Wall‐6

ws_profile‐7

# NameinFLUENT

observaIons

1 mass‐flow‐inlet‐4

Type:mass‐flow‐inlet

2 Pressure‐outlet‐8

Type:ouAlow

3 river_bed‐5

Type:wall,NoSlip

4 Wall‐6 Type:wall

5 ws_profile‐7

Type:symmetry

ModelconfiguraIoninOpenFOAMChooseanappropriatesolver

Equa&onssolved:

1con&nuityequa&on

3momentumequa&ons

1turbulentkine&cenergyequa&on,k

1rateofturbulentdissipa&onequa&on,epsilon

Total=6equa&onswith6unknowns(u,v,w,p,k,epsilon)

simpleFOAM: steady‐state solver for incompressible, turbulent flow. UseSIMPLEalgorithm.

ModelconfiguraIoninOpenFOAMBCFLUENTvs.OpenFOAM


Pressure‐outlet‐8

river_bed‐5

Wall‐6

ws_profile‐7(measured)

NameinFLUENT

TypeinFLUENT

NameinOpenFOAM

TypeinOpenFOAM


Massflowinlet

mass_flow_inlet_4 flowRateInletVelocity

pressure‐outlet‐8

Pressureoutlet

pressure_outlet_8 flowRateInletVelocity(Useminussign)

Wall‐6 wall wall_6 wall

river_bed‐5

WallNoslip

river_bed_5 wall

ws_profile‐7

Symmetry ws_profile_7 symmetryPlane

Filename mass_flow_inlet_4 pressure_outlet_8 wall_6 river_bed_5 ws_profile_7

epsilonRateofturbulentdissipa&on

“fixedValue”1e‐6

“zeroGradient” “epsilonWallFunc&on” “epsilonWallFunc&on” “symmetryPlane”

kTurbulentkine&cenergy

“fixedValue”1e‐6

“zeroGradient” “kqRWallFunc&on” “kqRWallFunc&on” “symmetryPlane”

nutKinema&ceddyviscosity

“calculated” “calculated” “nutWallFunc&on” “nutWallFunc&on” “symmetryPlane”

pPressure

“zeroGradient” “fixedValue” “zeroGradient” “zeroGradient” “symmetryPlane”

UVelocity

“flowRateInletVelocity”6.3m^3/s(13‐Jul‐09)

“flowRateInletVelocity”‐6.3m^3/s

“zeroGradient” “zeroGradient” “symmetryPlane”

InOpenFOAMweneedanexplicitdefini&onoftheBCforeachvariable.

ModelconfiguraIoninOpenFOAMNumericalschemes,Solvers,orthogonalcorrectorsandrelaxa2onfactors

TerminequaIons Schemeselected

ddtSchemes defaultsteadyState;

gradSchemes defaultGausslinear;grad(p)Gausslinear;grad(U)Gausslinear;

divSchemes defaultnone;div(phi,U)Gaussupwind;div(phi,k)Gaussupwind;div(phi,epsilon)Gaussupwind;div((nuEff*dev(grad(U).T())))Gausslinear;

laplacianSchemes defaultnone;laplacian(nuEff,U)Gausslinearcorrected;laplacian((1|A(U)),p)Gausslinearcorrected;laplacian(DkEff,k)Gausslinearcorrected;laplacian(DepsilonEff,epsilon)Gausslinearcorrected;

interpola&onSchemes defaultlinear;interpolate(U)linear;

snGradSchemes defaultcorrected;

variable RelaxaIonfactor

p 0.3

U 0.3

k 0.8

epsilon 0.8

variable solver precondiIoner tolerance relTol

p ICCG DIC 1e‐06 0.001

U PBiGC DILU 1e‐05 0.001

k PBiGC DILU 1e‐05 0.001

epsilon PBiGC DILU 1e‐05 0.001

SIMPLE{nNonOrthogonalCorrectors0;}

ModelconfiguraIoninOpenFOAMComputerconfigura2on&Generalresults

•  RedHatEnterpriseLinuxWorksta&on,8processors2.4GHz,withMemory235GiB

•  OpenFOAM,2000itera&ons2.36hours,(parallelrunning,mpi)•  Con&nuity=2.65511e‐06,•  k=‐1.0185e‐12,•  epsilon=‐2.18856e‐15

•  FLUENT,2000itera&ons2.1hours,•  Con&nuity=7.8657e‐04,•  k=2.7131e‐05,•  epsilon=2.8660e‐05

GeneralResultsTurbulentKine2cEnergy(m2/s2)

GeneralResultsTurbulentEnergyDissipaIon(m2/s3)

GeneralResultsPressure(pa)

OpenFOAM FLUENT

GeneralResultsContoursofVelocityMagnitude,CVM(m/s)

GeneralResults…ContoursofVelocityMagnitude,CVM(m/s)

GeneralResults..ContoursofVelocityMagnitude,CVM(m/s)

RedmeansthatOpenFOAMresultsarehigherthanFLUENTresults(velocitymagnitude)

V5=V4[1]‐V4[2]V4[1]:vel.Mag.OpenFOAMV4[2]:vel.Mag.FLUENT

BluemeansthatOpenFOAMresultsarelowerthanFLUENTresults(velocitymagnitude)

GeneralResultsCVM+pointVel.Mag.Alongapath(m/s)

downstream

Topgraph:velocitymagnitudeV.S.rela&vedistance,asshowedinthemapatthelew

Boxomgraph:rela&veerrorinm/s,FLUENTminusOpenFOAMresults

VelocityMagnitudeContours(m/s)OpenFOAM

GeneralResultsCVM+pointVel.Mag.Alongapath(m/s)

Topgraph:velocitymagnitudeVSrela&vedistance,asshowedinthemapattheright

Boxomgraph:rela&veerrorinm/s,FLUENTminusOpenFOAMresults

VelocityMagnitudeContours(m/s)OpenFOAM

GeneralResultsComparisonofvelocityvectors(m/s)

CS_50

CS_100


Generalview


Generalview

CS_900

CS_1100CS_1300

CS_1550

CS_900

CS_1100

CS_1300

CS_900

CS_1100

CS_1300

CS_1550 CS_1550

GeneralResultsCVM(m/s)+Streamlines

OpenFOAMFLUENT

Conclusions

  Successfulimplementa&oninOpenFOAMofsteadyturbulentflow.  These results show that the obtained solu&ons are similar, showing the

samepaxernsinbothcases.Onesector,whentheriverreducesitscrosssec&on, at the downstream end of the domain shows the highestdifferencesinthevelocityfield.

  The maximum difference in percentage for the velocity magnitude isaround50%andthesmallestis3%

  Theresidualsobtained inOpenFOAMaresmaller than thoseobtained inFLUENTforlessnumberofitera&ons.

  In general, this work shows a successful comparison of OpenFOAM andFLUENTforasteadyflowforsimilarboundaryandini&alcondi&ons.

  Furthermore,theresultsshowsthatOpenFOAMreproduceasmoothflowfieldinthecasestudythanFLUENT.

  Finally, theOpenFOAMsowwareshowsgreatflexibilitywhenapplyinganexis&ngmodeltoapar&cularcase.

Acknowledgments

•  OpenFOAMgroupIIHR.Marcela,Douglas,Yushi,Antonio.(TheUniversityofIowa,USA)

•  E.C.I.J.G.:“EscuelaColombianadeIngenieriaJulioGaravito”(Bogota,Colombia)

References

•  [1]M.Schubert,Computa&onalFluidDynamicsApplica&onsforNitrateremovalinaUpperMississippiRiverBackwater.MasterofSciencethesisCivilandEnvironmentalGraduateCollege,UniversityofIowa(2009).

•  [2]H.Jasak.ErrorAnalysisandEs&ma&onfortheFiniteVolumeMethodwithApplica&onstoFluidFlows.PhDthesis,UniversityofLondon(1996)

•  [3]OpenFOAM.TheOpenSourceCFDToolkit,UserGuide.(2004)

•  [4]OpenFOAM.TheOpenSourceCFDToolkit,Programmer’sGuide.(2004)

Thankyou!!

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comparison of openfoam and fluent for … of openfoam® and fluent for steady, viscous flow at pool...

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