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[302.044] Numerical Methodsin Fluid Dynamics
2�D Bwd-Facing StepIncompressible Navier�Stokes (simpleFoam),
SIMPLE Algorithm and Turbulence Models
Univ. Assist. MSc. Francesco Romanò
francesco.romano@tuwien.ac.at
January 8th, 2015
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
Outline
1 Incompressible Navier�Stokes
2 Backward�Facing Step
3 simpleFoam
Turbulence Model
Meshing
Solver Set-up
Mesh Re�nement
SIMPLE Algorithm
[302.044] � Univ. Assist. MSc. Francesco Romanò 2/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Incompressible Navier�StokesEquations
Incompressible Navier�Stokes Equations
∇ · u = 0
∇ · (uu) +∇ · (νeff∇u) = −∇p+BC & IC
+Turbulence parameters
u = velocity �eld;p = relative pressure �eld divided by ρ;νeff = e�ective kinematic viscosity.
[302.044] � Univ. Assist. MSc. Francesco Romanò 3/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Incompressible Navier�StokesEquations
Incompressible Navier�Stokes Equations∇ · u = 0
∇ · (uu) +∇ · (νeff∇u) = −∇p+BC & IC
+Turbulence parameters
u = velocity �eld;p = relative pressure �eld divided by ρ;νeff = e�ective kinematic viscosity.
[302.044] � Univ. Assist. MSc. Francesco Romanò 3/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Incompressible Navier�StokesEquations
Incompressible Navier�Stokes Equations∇ · u = 0
∇ · (uu) +∇ · (νeff∇u) = −∇p+BC & IC
+Turbulence parameters
u = velocity �eld;p = relative pressure �eld divided by ρ;νeff = e�ective kinematic viscosity.
[302.044] � Univ. Assist. MSc. Francesco Romanò 3/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepMathematical Problem
Backward�Facing Step Problem
∇ · u = 0
∇ · (uu) +∇ · (νeff∇u) = −∇p
BC :
left edge: Inlet → u = 10 m/s i;
step: No�Slip → u = 0;
right edge: Out�ow → p = 0;
bottom edge: No�Slip → u = 0;
top edge: No�Slip → u = 0;
IC : u = 0 , (p = 0);
Turbulence parameters
u = velocity �eld;p = relative pressure �eld divided by ρ;νeff = e�ective kinematic viscosity.
[302.044] � Univ. Assist. MSc. Francesco Romanò 4/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepMathematical Problem
Backward�Facing Step Problem
∇ · u = 0
∇ · (uu) +∇ · (νeff∇u) = −∇p
BC :
left edge: Inlet → u = 10 m/s i;
step: No�Slip → u = 0;
right edge: Out�ow → p = 0;
bottom edge: No�Slip → u = 0;
top edge: No�Slip → u = 0;
IC : u = 0 , (p = 0);
Turbulence parameters
u = velocity �eld;p = relative pressure �eld divided by ρ;νeff = e�ective kinematic viscosity.
[302.044] � Univ. Assist. MSc. Francesco Romanò 4/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver
. simpleFoam assumes an incompressible, steady, viscous�ow;
. simpleFoam has full access to all the turbulence models inthe incompressibleTurbulenceModels library and thenon-Newtonian ones in incompressibleTransportModels
library implemented in OpenFOAM:
[302.044] � Univ. Assist. MSc. Francesco Romanò 5/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver
. simpleFoam assumes an incompressible, steady, viscous�ow;
. simpleFoam has full access to all the turbulence models inthe incompressibleTurbulenceModels library and thenon-Newtonian ones in incompressibleTransportModels
library implemented in OpenFOAM:
[302.044] � Univ. Assist. MSc. Francesco Romanò 5/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver
. simpleFoam assumes an incompressible, steady, viscous�ow;
. simpleFoam has full access to all the turbulence models inthe incompressibleTurbulenceModels library and thenon-Newtonian ones in incompressibleTransportModels
library implemented in OpenFOAM:
[302.044] � Univ. Assist. MSc. Francesco Romanò 5/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver
. simpleFoam assumes an incompressible, steady, viscous�ow;
. simpleFoam has full access to all the turbulence models inthe incompressibleTurbulenceModels library and thenon-Newtonian ones in incompressibleTransportModels
library implemented in OpenFOAM:
[302.044] � Univ. Assist. MSc. Francesco Romanò 5/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver
. simpleFoam assumes an incompressible, steady, viscous�ow;
. simpleFoam has full access to all the turbulence models inthe incompressibleTurbulenceModels library and thenon-Newtonian ones in incompressibleTransportModels
library implemented in OpenFOAM;
. Solving the NSEs using a RANS (Reynolds AveragedNavier-Stokes) model implies that the simulation cannotrepresent the turbulence phenomenon in all its scales, butit just mimes its macroscopical e�ects;
. Considering turbulence models, in transportProperties isnecessary to set the properties of the chosen model1.
1In this case, the k − ε turbulence model will be used[302.044] � Univ. Assist. MSc. Francesco Romanò 6/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver
. simpleFoam assumes an incompressible, steady, viscous�ow;
. simpleFoam has full access to all the turbulence models inthe incompressibleTurbulenceModels library and thenon-Newtonian ones in incompressibleTransportModels
library implemented in OpenFOAM;
. Solving the NSEs using a RANS (Reynolds AveragedNavier-Stokes) model implies that the simulation cannotrepresent the turbulence phenomenon in all its scales, butit just mimes its macroscopical e�ects;
. Considering turbulence models, in transportProperties isnecessary to set the properties of the chosen model1.
1In this case, the k − ε turbulence model will be used[302.044] � Univ. Assist. MSc. Francesco Romanò 6/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver
. simpleFoam assumes an incompressible, steady, viscous�ow;
. simpleFoam has full access to all the turbulence models inthe incompressibleTurbulenceModels library and thenon-Newtonian ones in incompressibleTransportModels
library implemented in OpenFOAM;
. Solving the NSEs using a RANS (Reynolds AveragedNavier-Stokes) model implies that the simulation cannotrepresent the turbulence phenomenon in all its scales, butit just mimes its macroscopical e�ects;
. Considering turbulence models, in transportProperties isnecessary to set the properties of the chosen model1.
1In this case, the k − ε turbulence model will be used[302.044] � Univ. Assist. MSc. Francesco Romanò 6/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: k − ε Model
(ρk) ,t+(ρkui) ,xi =[(µ′ + µt
σk
)k,xj
]+
Pk + Pb − ρε− YM + Sk
(ρε) ,t+(ρεui) ,xi =[(µ′ + µt
σε
)ε,xj
]+
C1εεk (Pk + C3εPb)− C2ερ
ε2
k + Sε
where: k = Turbulent kinetic energy , ε = Dissipation
µt = ρCµk2
ε, Pk = −ρu′iu′j
∂uj∂xi
= µtS2 = µt2SijSij
S = Modulus of the mean rate-of-strain tensor
Pb = βgiµtPrt
T,xi , β = −1
ρρ,T |p
C1ε = 1.44 , C2ε = 1.92 , Cµ = 0.09 , σk = 1.0 , σε = 1.3
[302.044] � Univ. Assist. MSc. Francesco Romanò 7/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: k − ε Model
(ρk) ,t+(ρkui) ,xi =[(µ′ + µt
σk
)k,xj
]+
Pk + Pb − ρε− YM + Sk
(ρε) ,t+(ρεui) ,xi =[(µ′ + µt
σε
)ε,xj
]+
C1εεk (Pk + C3εPb)− C2ερ
ε2
k + Sε
where: k = Turbulent kinetic energy , ε = Dissipation
µt = ρCµk2
ε, Pk = −ρu′iu′j
∂uj∂xi
= µtS2 = µt2SijSij
S = Modulus of the mean rate-of-strain tensor
Pb = βgiµtPrt
T,xi , β = −1
ρρ,T |p
C1ε = 1.44 , C2ε = 1.92 , Cµ = 0.09 , σk = 1.0 , σε = 1.3[302.044] � Univ. Assist. MSc. Francesco Romanò 7/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: k − ε Model
. The k − ε model needs initial conditions to be set;
. The following hypothesis will be used for the simulation ofthe Backward-Facing Step case:
◦ isotropic initial turbulence;◦ initial turbulence �uctuation intensity: 5%;◦ turbulent reference length scale: 10%;
. The correspondent parameters set-up is then resulting:
u′ = v′ = w′ = 5%Uin = 0.5m/s
k =3
2(0.5m/s)
2= 0.375m2/s2
ε =C0.75µ k1.5
l=
0.090.75 · 0.3751.5
0.1 · 25.4 · 10−3m2/s3 = 14.855m2/s3
[302.044] � Univ. Assist. MSc. Francesco Romanò 8/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: k − ε Model
. The k − ε model needs initial conditions to be set;
. The following hypothesis will be used for the simulation ofthe Backward-Facing Step case:
◦ isotropic initial turbulence;◦ initial turbulence �uctuation intensity: 5%;◦ turbulent reference length scale: 10%;
. The correspondent parameters set-up is then resulting:
u′ = v′ = w′ = 5%Uin = 0.5m/s
k =3
2(0.5m/s)
2= 0.375m2/s2
ε =C0.75µ k1.5
l=
0.090.75 · 0.3751.5
0.1 · 25.4 · 10−3m2/s3 = 14.855m2/s3
[302.044] � Univ. Assist. MSc. Francesco Romanò 8/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: k − ε Model
. The k − ε model needs initial conditions to be set;
. The following hypothesis will be used for the simulation ofthe Backward-Facing Step case:
◦ isotropic initial turbulence;◦ initial turbulence �uctuation intensity: 5%;◦ turbulent reference length scale: 10%;
. The correspondent parameters set-up is then resulting:
u′ = v′ = w′ = 5%Uin = 0.5m/s
k =3
2(0.5m/s)
2= 0.375m2/s2
ε =C0.75µ k1.5
l=
0.090.75 · 0.3751.5
0.1 · 25.4 · 10−3m2/s3 = 14.855m2/s3
[302.044] � Univ. Assist. MSc. Francesco Romanò 8/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: k − ε Model
. The k − ε model needs initial conditions to be set;
. The following hypothesis will be used for the simulation ofthe Backward-Facing Step case:
◦ isotropic initial turbulence;
◦ initial turbulence �uctuation intensity: 5%;◦ turbulent reference length scale: 10%;
. The correspondent parameters set-up is then resulting:
u′ = v′ = w′ = 5%Uin = 0.5m/s
k =3
2(0.5m/s)
2= 0.375m2/s2
ε =C0.75µ k1.5
l=
0.090.75 · 0.3751.5
0.1 · 25.4 · 10−3m2/s3 = 14.855m2/s3
[302.044] � Univ. Assist. MSc. Francesco Romanò 8/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: k − ε Model
. The k − ε model needs initial conditions to be set;
. The following hypothesis will be used for the simulation ofthe Backward-Facing Step case:
◦ isotropic initial turbulence;◦ initial turbulence �uctuation intensity: 5%;
◦ turbulent reference length scale: 10%;
. The correspondent parameters set-up is then resulting:
u′ = v′ = w′ = 5%Uin = 0.5m/s
k =3
2(0.5m/s)
2= 0.375m2/s2
ε =C0.75µ k1.5
l=
0.090.75 · 0.3751.5
0.1 · 25.4 · 10−3m2/s3 = 14.855m2/s3
[302.044] � Univ. Assist. MSc. Francesco Romanò 8/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: k − ε Model
. The k − ε model needs initial conditions to be set;
. The following hypothesis will be used for the simulation ofthe Backward-Facing Step case:
◦ isotropic initial turbulence;◦ initial turbulence �uctuation intensity: 5%;◦ turbulent reference length scale: 10%;
. The correspondent parameters set-up is then resulting:
u′ = v′ = w′ = 5%Uin = 0.5m/s
k =3
2(0.5m/s)
2= 0.375m2/s2
ε =C0.75µ k1.5
l=
0.090.75 · 0.3751.5
0.1 · 25.4 · 10−3m2/s3 = 14.855m2/s3
[302.044] � Univ. Assist. MSc. Francesco Romanò 8/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: k − ε Model
. The k − ε model needs initial conditions to be set;
. The following hypothesis will be used for the simulation ofthe Backward-Facing Step case:
◦ isotropic initial turbulence;◦ initial turbulence �uctuation intensity: 5%;◦ turbulent reference length scale: 10%;
. The correspondent parameters set-up is then resulting:
u′ = v′ = w′ = 5%Uin = 0.5m/s
k =3
2(0.5m/s)
2= 0.375m2/s2
ε =C0.75µ k1.5
l=
0.090.75 · 0.3751.5
0.1 · 25.4 · 10−3m2/s3 = 14.855m2/s3
[302.044] � Univ. Assist. MSc. Francesco Romanò 8/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Meshing
. As mesh, a very coarse non-orthogonal one is employed:
. Algorithm steps:
◦ create the geometry writing the blockMeshDict �le andlocating it in <problem_folder>/constant/polyMesh/;
◦ run the command <problem_folder>$ blockMesh.
[302.044] � Univ. Assist. MSc. Francesco Romanò 9/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Meshing
. As mesh, a very coarse non-orthogonal one is employed:
. Algorithm steps:
◦ create the geometry writing the blockMeshDict �le andlocating it in <problem_folder>/constant/polyMesh/;
◦ run the command <problem_folder>$ blockMesh.
[302.044] � Univ. Assist. MSc. Francesco Romanò 9/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Meshing
. As mesh, a very coarse non-orthogonal one is employed:
. Algorithm steps:
◦ create the geometry writing the blockMeshDict �le andlocating it in <problem_folder>/constant/polyMesh/;
◦ run the command <problem_folder>$ blockMesh.
[302.044] � Univ. Assist. MSc. Francesco Romanò 9/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Meshing
. As mesh, a very coarse non-orthogonal one is employed:
. Algorithm steps:
◦ create the geometry writing the blockMeshDict �le andlocating it in <problem_folder>/constant/polyMesh/;
◦ run the command <problem_folder>$ blockMesh.
[302.044] � Univ. Assist. MSc. Francesco Romanò 9/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Meshing
. As mesh, a very coarse non-orthogonal one is employed:
. Algorithm steps:
◦ create the geometry writing the blockMeshDict �le andlocating it in <problem_folder>/constant/polyMesh/;
◦ run the command <problem_folder>$ blockMesh.
[302.044] � Univ. Assist. MSc. Francesco Romanò 9/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Solver Set-up
. For an incompressible, viscous �ow, considering a turbulentregime, not only the the kinematic viscosity has to bede�ned in transportProperties. To be set are theturbulence parameters, too;
. In order to choose the turbulence model to use (k− ε in thiscase) a RASProperties dictionary has to be written;
. Because the employed grid is slightly Non-Orthogonal,the �ag nNonOrthogonalCorrectors in fvSolution is setto 0;
[302.044] � Univ. Assist. MSc. Francesco Romanò 10/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Solver Set-up
. For an incompressible, viscous �ow, considering a turbulentregime, not only the the kinematic viscosity has to bede�ned in transportProperties. To be set are theturbulence parameters, too;
. In order to choose the turbulence model to use (k− ε in thiscase) a RASProperties dictionary has to be written;
. Because the employed grid is slightly Non-Orthogonal,the �ag nNonOrthogonalCorrectors in fvSolution is setto 0;
[302.044] � Univ. Assist. MSc. Francesco Romanò 10/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Solver Set-up
. For an incompressible, viscous �ow, considering a turbulentregime, not only the the kinematic viscosity has to bede�ned in transportProperties. To be set are theturbulence parameters, too;
. In order to choose the turbulence model to use (k− ε in thiscase) a RASProperties dictionary has to be written;
. Because the employed grid is slightly Non-Orthogonal,the �ag nNonOrthogonalCorrectors in fvSolution is setto 0;
[302.044] � Univ. Assist. MSc. Francesco Romanò 10/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Solver Set-up
. For an incompressible, viscous �ow, considering a turbulentregime, not only the the kinematic viscosity has to bede�ned in transportProperties. To be set are theturbulence parameters, too;
. In order to choose the turbulence model to use (k− ε in thiscase) a RASProperties dictionary has to be written;
. Because the employed grid is slightly Non-Orthogonal,the �ag nNonOrthogonalCorrectors in fvSolution is setto 0;
[302.044] � Univ. Assist. MSc. Francesco Romanò 10/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Solver Set-up
. Algorithm steps:
◦ set the �uid and turbulent model properties intransportProperties and RASProperties and locatethem in <problem_folder>/constant/;
◦ set the initial conditions in the p, U, epsilon, k, nut andnuTilda �les and locate them in <problem_folder>/0/;
◦ set time step and data saving/storing options writingthe controlDict �le and locate it in<problem_folder>/system/;
◦ set discretization and splitting scheme details writingthe fvSchemes and fvSolution �les and locate themin <problem_folder>/system/;
◦ run the solver using <problem_folder>$ simpleFoam;◦ visualize with <problem_folder>$ paraFoam.
[302.044] � Univ. Assist. MSc. Francesco Romanò 11/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Solver Set-up
. Algorithm steps:
◦ set the �uid and turbulent model properties intransportProperties and RASProperties and locatethem in <problem_folder>/constant/;
◦ set the initial conditions in the p, U, epsilon, k, nut andnuTilda �les and locate them in <problem_folder>/0/;
◦ set time step and data saving/storing options writingthe controlDict �le and locate it in<problem_folder>/system/;
◦ set discretization and splitting scheme details writingthe fvSchemes and fvSolution �les and locate themin <problem_folder>/system/;
◦ run the solver using <problem_folder>$ simpleFoam;◦ visualize with <problem_folder>$ paraFoam.
[302.044] � Univ. Assist. MSc. Francesco Romanò 11/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Solver Set-up
. Algorithm steps:
◦ set the �uid and turbulent model properties intransportProperties and RASProperties and locatethem in <problem_folder>/constant/;
◦ set the initial conditions in the p, U, epsilon, k, nut andnuTilda �les and locate them in <problem_folder>/0/;
◦ set time step and data saving/storing options writingthe controlDict �le and locate it in<problem_folder>/system/;
◦ set discretization and splitting scheme details writingthe fvSchemes and fvSolution �les and locate themin <problem_folder>/system/;
◦ run the solver using <problem_folder>$ simpleFoam;◦ visualize with <problem_folder>$ paraFoam.
[302.044] � Univ. Assist. MSc. Francesco Romanò 11/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Solver Set-up
. Algorithm steps:
◦ set the �uid and turbulent model properties intransportProperties and RASProperties and locatethem in <problem_folder>/constant/;
◦ set the initial conditions in the p, U, epsilon, k, nut andnuTilda �les and locate them in <problem_folder>/0/;
◦ set time step and data saving/storing options writingthe controlDict �le and locate it in<problem_folder>/system/;
◦ set discretization and splitting scheme details writingthe fvSchemes and fvSolution �les and locate themin <problem_folder>/system/;
◦ run the solver using <problem_folder>$ simpleFoam;◦ visualize with <problem_folder>$ paraFoam.
[302.044] � Univ. Assist. MSc. Francesco Romanò 11/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Solver Set-up
. Algorithm steps:
◦ set the �uid and turbulent model properties intransportProperties and RASProperties and locatethem in <problem_folder>/constant/;
◦ set the initial conditions in the p, U, epsilon, k, nut andnuTilda �les and locate them in <problem_folder>/0/;
◦ set time step and data saving/storing options writingthe controlDict �le and locate it in<problem_folder>/system/;
◦ set discretization and splitting scheme details writingthe fvSchemes and fvSolution �les and locate themin <problem_folder>/system/;
◦ run the solver using <problem_folder>$ simpleFoam;◦ visualize with <problem_folder>$ paraFoam.
[302.044] � Univ. Assist. MSc. Francesco Romanò 11/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Solver Set-up
. Algorithm steps:
◦ set the �uid and turbulent model properties intransportProperties and RASProperties and locatethem in <problem_folder>/constant/;
◦ set the initial conditions in the p, U, epsilon, k, nut andnuTilda �les and locate them in <problem_folder>/0/;
◦ set time step and data saving/storing options writingthe controlDict �le and locate it in<problem_folder>/system/;
◦ set discretization and splitting scheme details writingthe fvSchemes and fvSolution �les and locate themin <problem_folder>/system/;
◦ run the solver using <problem_folder>$ simpleFoam;◦ visualize with <problem_folder>$ paraFoam.
[302.044] � Univ. Assist. MSc. Francesco Romanò 11/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Solver Set-up
. Algorithm steps:
◦ set the �uid and turbulent model properties intransportProperties and RASProperties and locatethem in <problem_folder>/constant/;
◦ set the initial conditions in the p, U, epsilon, k, nut andnuTilda �les and locate them in <problem_folder>/0/;
◦ set time step and data saving/storing options writingthe controlDict �le and locate it in<problem_folder>/system/;
◦ set discretization and splitting scheme details writingthe fvSchemes and fvSolution �les and locate themin <problem_folder>/system/;
◦ run the solver using <problem_folder>$ simpleFoam;◦ visualize with <problem_folder>$ paraFoam.
[302.044] � Univ. Assist. MSc. Francesco Romanò 11/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Solver Set-up
. Algorithm steps:
◦ set the �uid and turbulent model properties intransportProperties and RASProperties and locatethem in <problem_folder>/constant/;
◦ set the initial conditions in the p, U, epsilon, k, nut andnuTilda �les and locate them in <problem_folder>/0/;
◦ set time step and data saving/storing options writingthe controlDict �le and locate it in<problem_folder>/system/;
◦ set discretization and splitting scheme details writingthe fvSchemes and fvSolution �les and locate themin <problem_folder>/system/;
◦ run the solver using <problem_folder>$ simpleFoam;
◦ visualize with <problem_folder>$ paraFoam.
[302.044] � Univ. Assist. MSc. Francesco Romanò 11/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Solver Set-up
. Algorithm steps:
◦ set the �uid and turbulent model properties intransportProperties and RASProperties and locatethem in <problem_folder>/constant/;
◦ set the initial conditions in the p, U, epsilon, k, nut andnuTilda �les and locate them in <problem_folder>/0/;
◦ set time step and data saving/storing options writingthe controlDict �le and locate it in<problem_folder>/system/;
◦ set discretization and splitting scheme details writingthe fvSchemes and fvSolution �les and locate themin <problem_folder>/system/;
◦ run the solver using <problem_folder>$ simpleFoam;◦ visualize with <problem_folder>$ paraFoam.
[302.044] � Univ. Assist. MSc. Francesco Romanò 11/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Solver Set-up
. Case folder structure:
→ <problem_folder>/
→ 0/
U p
epsilon k
nut nuTilda
→ constant/
transportProperties
RASProperties
→ polyMesh/
blockMeshDict
→ system/
controlDict
fvSchemes
fvSolution
[302.044] � Univ. Assist. MSc. Francesco Romanò 12/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Mesh Re�nement
. It is expectable that, considering the complexity of the �ow,a graded mesh is needful;
. Generally speaking, the regions of highest shear areparticularly critical, so they require the �nest grid;
. The inlet uniform �ow passing over the step generates shearon the �uid below (through a vortex in the bottom part ofthe domain). Therefore, the region of high shear will benearby both: the centreline and the walls.
[302.044] � Univ. Assist. MSc. Francesco Romanò 13/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Mesh Re�nement
. It is expectable that, considering the complexity of the �ow,a graded mesh is needful;
. Generally speaking, the regions of highest shear areparticularly critical, so they require the �nest grid;
. The inlet uniform �ow passing over the step generates shearon the �uid below (through a vortex in the bottom part ofthe domain). Therefore, the region of high shear will benearby both: the centreline and the walls.
[302.044] � Univ. Assist. MSc. Francesco Romanò 13/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: Mesh Re�nement
. It is expectable that, considering the complexity of the �ow,a graded mesh is needful;
. Generally speaking, the regions of highest shear areparticularly critical, so they require the �nest grid;
. The inlet uniform �ow passing over the step generates shearon the �uid below (through a vortex in the bottom part ofthe domain). Therefore, the region of high shear will benearby both: the centreline and the walls.
[302.044] � Univ. Assist. MSc. Francesco Romanò 13/14
IncompressibleNavier�Stokes
Backward�FacingStep
simpleFoam
TurbulenceModel
Meshing
Solver Set-up
MeshRe�nement
SIMPLEAlgorithm
2�D Backward�Facing StepOpenFOAM simpleFoam Solver
OpenFOAM simpleFoam Solver: SIMPLE Algorithm
[302.044] � Univ. Assist. MSc. Francesco Romanò 14/14
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