CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > General Forums > Main CFD Forum

Specifying initial conditions with cyclic boundary conditions

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree1Likes
  • 1 Post By LuckyTran

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 13, 2018, 16:59
Default Specifying initial conditions with cyclic boundary conditions
  #1
Member
 
Join Date: Apr 2016
Posts: 30
Rep Power: 6
shanvach is on a distinguished road
Hi all,

I am trying to use a modified transient twoPhaseEulerFoam with cyclic boundary conditions. Now I have to specify the initial volume fractions,velocities,pressures etc at the INLET. How do I do that because I have specified cyclic in the boundary conditions?
How do I specify initial non uniform internal field values without using the list option since the mesh is complex?

Thanks and regards,
Shantanu Vachhani
shanvach is offline   Reply With Quote

Old   November 14, 2018, 11:07
Default
  #2
Senior Member
 
Lucky Tran
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 4,013
Rep Power: 48
LuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura about
cyclic is the entry for type that you need to specify (for every field). There's still an entry for value that you need to specify (for every field). That's where your initial condition goes.
LuckyTran is offline   Reply With Quote

Old   November 14, 2018, 15:19
Default
  #3
Member
 
Join Date: Apr 2016
Posts: 30
Rep Power: 6
shanvach is on a distinguished road
Even after entering a value at the boundary while zero in the uniform field, the simulation doesn't take that into consideration because the alpha(volume fraction) values are zero at every time step. Furthermore , the courant number is very less because I have specified non zero velocity at the inlet while the internal filed is (0 0 0).
Could you think of a reason why is this happening?

Thanks and Regards,
Shantanu Vachhani

Code:
Courant Number mean: 2.29238e-15 max: 3.88904e-15
Max Ur Courant Number = 2.49311e-16
Time = 1.5e-05

PIMPLE: iteration 1
MULES: Solving for alpha.air
MULES: Solving for alpha.air
alpha.air volume fraction = 0  Min(alpha.air) = 0  Max(alpha.air) = 0
Constructing momentum equations
Selecting patchDistMethod meshWave
Selecting patchDistMethod meshWave
--> FOAM Warning : 
    From function const volVectorField& Foam::wallDist::n() const
    in file fvMesh/wallDist/wallDist/wallDist.C at line 200
    n requested but 'nRequired' not specified in the wallDist dictionary
    Recalculating y and n fields.
smoothSolver:  Solving for e.air, Initial residual = 1, Final residual = 1, No Iterations 0
smoothSolver:  Solving for e.water, Initial residual = 0.999662, Final residual = 0.999662, No Iterations 0
min T.air 300.01
min T.water 300.002
smoothSolver:  Solving for p_rgh, Initial residual = 0.999985, Final residual = 1.14001e-05, No Iterations 1000
PIMPLE: iteration 2
MULES: Solving for alpha.air
MULES: Solving for alpha.air
alpha.air volume fraction = 0  Min(alpha.air) = 0  Max(alpha.air) = 0
Constructing momentum equations
Selecting patchDistMethod meshWave
Selecting patchDistMethod meshWave
--> FOAM Warning : 
    From function const volVectorField& Foam::wallDist::n() const
    in file fvMesh/wallDist/wallDist/wallDist.C at line 200
    n requested but 'nRequired' not specified in the wallDist dictionary
    Recalculating y and n fields.
smoothSolver:  Solving for e.air, Initial residual = 1, Final residual = 1, No Iterations 0
smoothSolver:  Solving for e.water, Initial residual = 0.999683, Final residual = 0.999683, No Iterations 0
min T.air 300.01
min T.water 300.002
smoothSolver:  Solving for p_rgh, Initial residual = 0.999994, Final residual = 1.07173e-05, No Iterations 1000
PIMPLE: iteration 3
MULES: Solving for alpha.air
MULES: Solving for alpha.air
alpha.air volume fraction = 0  Min(alpha.air) = 0  Max(alpha.air) = 0
Constructing momentum equations
Selecting patchDistMethod meshWave
Selecting patchDistMethod meshWave
--> FOAM Warning : 
    From function const volVectorField& Foam::wallDist::n() const
    in file fvMesh/wallDist/wallDist/wallDist.C at line 200
    n requested but 'nRequired' not specified in the wallDist dictionary
    Recalculating y and n fields.
smoothSolver:  Solving for e.air, Initial residual = 1, Final residual = 1, No Iterations 0
smoothSolver:  Solving for e.water, Initial residual = 0.999698, Final residual = 0.999698, No Iterations 0
min T.air 300.01
min T.water 300.002
smoothSolver:  Solving for p_rgh, Initial residual = 0.999992, Final residual = 9.86466e-06, No Iterations 1000
Constructing momentum equations
Selecting patchDistMethod meshWave
Selecting patchDistMethod meshWave
--> FOAM Warning : 
    From function const volVectorField& Foam::wallDist::n() const
    in file fvMesh/wallDist/wallDist/wallDist.C at line 200
    n requested but 'nRequired' not specified in the wallDist dictionary
    Recalculating y and n fields.
GAMG:  Solving for psi, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 101.63 s


Courant Number mean: 1.542e-15 max: 2.61096e-15
Max Ur Courant Number = 1.60923e-16
Time = 2e-05

PIMPLE: iteration 1
MULES: Solving for alpha.air
MULES: Solving for alpha.air
alpha.air volume fraction = 0  Min(alpha.air) = 0  Max(alpha.air) = 0
Constructing momentum equations
Selecting patchDistMethod meshWave
Selecting patchDistMethod meshWave
--> FOAM Warning : 
    From function const volVectorField& Foam::wallDist::n() const
    in file fvMesh/wallDist/wallDist/wallDist.C at line 200
    n requested but 'nRequired' not specified in the wallDist dictionary
    Recalculating y and n fields.
smoothSolver:  Solving for e.air, Initial residual = 1, Final residual = 1, No Iterations 0
smoothSolver:  Solving for e.water, Initial residual = 0.999708, Final residual = 0.999708, No Iterations 0
min T.air 300.01
min T.water 300.002
smoothSolver:  Solving for p_rgh, Initial residual = 0.99999, Final residual = 8.67989e-06, No Iterations 1000
PIMPLE: iteration 2
MULES: Solving for alpha.air
MULES: Solving for alpha.air
alpha.air volume fraction = 0  Min(alpha.air) = 0  Max(alpha.air) = 0
Constructing momentum equations
Selecting patchDistMethod meshWave
Selecting patchDistMethod meshWave
--> FOAM Warning : 
    From function const volVectorField& Foam::wallDist::n() const
    in file fvMesh/wallDist/wallDist/wallDist.C at line 200
    n requested but 'nRequired' not specified in the wallDist dictionary
    Recalculating y and n fields.
smoothSolver:  Solving for e.air, Initial residual = 1, Final residual = 1, No Iterations 0
smoothSolver:  Solving for e.water, Initial residual = 0.999722, Final residual = 0.999722, No Iterations 0
min T.air 300.01
min T.water 300.002
smoothSolver:  Solving for p_rgh, Initial residual = 0.999996, Final residual = 8.37368e-06, No Iterations 1000
PIMPLE: iteration 3
MULES: Solving for alpha.air
MULES: Solving for alpha.air
alpha.air volume fraction = 0  Min(alpha.air) = 0  Max(alpha.air) = 0
Constructing momentum equations
Selecting patchDistMethod meshWave
Selecting patchDistMethod meshWave
--> FOAM Warning : 
    From function const volVectorField& Foam::wallDist::n() const
    in file fvMesh/wallDist/wallDist/wallDist.C at line 200
    n requested but 'nRequired' not specified in the wallDist dictionary
    Recalculating y and n fields.
smoothSolver:  Solving for e.air, Initial residual = 1, Final residual = 1, No Iterations 0
smoothSolver:  Solving for e.water, Initial residual = 0.999731, Final residual = 0.999731, No Iterations 0
min T.air 300.01
min T.water 300.002
smoothSolver:  Solving for p_rgh, Initial residual = 0.999995, Final residual = 7.84835e-06, No Iterations 1000
Constructing momentum equations
Selecting patchDistMethod meshWave
Selecting patchDistMethod meshWave
--> FOAM Warning : 
    From function const volVectorField& Foam::wallDist::n() const
    in file fvMesh/wallDist/wallDist/wallDist.C at line 200
    n requested but 'nRequired' not specified in the wallDist dictionary
    Recalculating y and n fields.
GAMG:  Solving for psi, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 134.49 s


Courant Number mean: 1.13366e-15 max: 1.91734e-15
Max Ur Courant Number = 1.08311e-16
Time = 2.5e-05

PIMPLE: iteration 1
MULES: Solving for alpha.air
MULES: Solving for alpha.air
alpha.air volume fraction = 0  Min(alpha.air) = 0  Max(alpha.air) = 0
Constructing momentum equations
Selecting patchDistMethod meshWave
Selecting patchDistMethod meshWave
--> FOAM Warning : 
    From function const volVectorField& Foam::wallDist::n() const
    in file fvMesh/wallDist/wallDist/wallDist.C at line 200
    n requested but 'nRequired' not specified in the wallDist dictionary
    Recalculating y and n fields.
smoothSolver:  Solving for e.air, Initial residual = 1, Final residual = 1, No Iterations 0
smoothSolver:  Solving for e.water, Initial residual = 0.999737, Final residual = 0.999737, No Iterations 0
min T.air 300.01
min T.water 300.002
smoothSolver:  Solving for p_rgh, Initial residual = 0.999994, Final residual = 7.00422e-06, No Iterations 1000
PIMPLE: iteration 2
MULES: Solving for alpha.air
MULES: Solving for alpha.air
alpha.air volume fraction = 0  Min(alpha.air) = 0  Max(alpha.air) = 0
Constructing momentum equations
Selecting patchDistMethod meshWave
Selecting patchDistMethod meshWave
--> FOAM Warning : 
    From function const volVectorField& Foam::wallDist::n() const
    in file fvMesh/wallDist/wallDist/wallDist.C at line 200
    n requested but 'nRequired' not specified in the wallDist dictionary
    Recalculating y and n fields.
smoothSolver:  Solving for e.air, Initial residual = 1, Final residual = 1, No Iterations 0
smoothSolver:  Solving for e.water, Initial residual = 0.999745, Final residual = 0.999745, No Iterations 0
min T.air 300.01
min T.water 300.002
smoothSolver:  Solving for p_rgh, Initial residual = 0.999998, Final residual = 6.72276e-06, No Iterations 1000
PIMPLE: iteration 3
MULES: Solving for alpha.air
MULES: Solving for alpha.air
alpha.air volume fraction = 0  Min(alpha.air) = 0  Max(alpha.air) = 0
Constructing momentum equations
Selecting patchDistMethod meshWave
Selecting patchDistMethod meshWave
--> FOAM Warning : 
    From function const volVectorField& Foam::wallDist::n() const
    in file fvMesh/wallDist/wallDist/wallDist.C at line 200
    n requested but 'nRequired' not specified in the wallDist dictionary
    Recalculating y and n fields.
smoothSolver:  Solving for e.air, Initial residual = 1, Final residual = 1, No Iterations 0
smoothSolver:  Solving for e.water, Initial residual = 0.999752, Final residual = 0.999752, No Iterations 0
min T.air 300.01
min T.water 300.002
shanvach is offline   Reply With Quote

Old   November 19, 2018, 12:55
Default
  #4
Senior Member
 
Lucky Tran
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 4,013
Rep Power: 48
LuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura about
I'm still confused what you are trying to do. With cyclic BC, there is no more an inlet.


Your initial condition is specified in value of the internalField and if you ordinary BC's the value of the boundaryField. But you have cyclic and no longer is it necessary to specify value in the boundaryField and only the internalField.


Now the question is what you like to specify as the initial condition for the internalField. And yes you must think in terms of internalField. Probably the solution will involve the setFields utility.
AliE likes this.
LuckyTran is offline   Reply With Quote

Old   November 26, 2018, 00:00
Default
  #5
Member
 
Join Date: Apr 2016
Posts: 30
Rep Power: 6
shanvach is on a distinguished road
LuckyTran,

Thank you for the response. However I have one question about using cyclic boundary condition. When I am using cyclic boundary condition , my internal field specified for volume fraction is 0.5. Now using cyclic boundary condition this value remains same throughout the domain as the simulation progresses. This means there is no mass transfer which is physically incorrect. When I use normal inlet and outlet boundary condition, observable mass transfer is observed. Could you think of the reason why cyclic boundary condition is giving wrong results?

Thanks and Regards,
Shantanu Vachhani
shanvach is offline   Reply With Quote

Reply

Tags
boundary condition, cyclic boundary condition, initial condition, internal, non uniform

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Wind turbine simulation Saturn CFX 58 July 3, 2020 01:13
chtMultiRegionSimpleFoam: maximum number of iterations excedeed. Nkl OpenFOAM Running, Solving & CFD 19 October 10, 2019 02:42
chtMultiRegionSimpleFoam turbulent case Aditya Patil OpenFOAM Running, Solving & CFD 6 April 24, 2017 22:13
Micro Scale Pore, icoFoam gooya_kabir OpenFOAM Running, Solving & CFD 2 November 2, 2013 13:58
calculation stops after few time steps sivakumar OpenFOAM Running, Solving & CFD 7 March 17, 2013 06:37


All times are GMT -4. The time now is 19:07.