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-   -   Pipe flow (http://www.cfd-online.com/Forums/openfoam-solving/60003-pipe-flow.html)

shuo September 21, 2006 21:36

Hello I have trying to fo c
 
Hello

I have trying to fo calculation for a laminar pipe flow. I fot results from using FLuent and wanted to compare them with those obtained using icoFoam. The mesh was imported sucessfully and compiled without errors to my knowledge.

Time = 0.5

Mean and max Courant Numbers = 4.1213e+77 1.56978e+79
BICCG: Solving for Ux, Initial residual = 1, Final residual = 30.5736, No Iterations 1001
BICCG: Solving for Uy, Initial residual = 1, Final residual = 37.0907, No Iterations 1001
ICCG: Solving for p, Initial residual = 1, Final residual = 4001.94, No Iterations 5001
time step continuity errors : sum local = 8.45863e+91, global = -3.96813e+87, cumulative = -3.96813e+87
ICCG: Solving for p, Initial residual = 1, Final residual = 0.689595, No Iterations 5001
time step continuity errors : sum local = 5.12229e+99, global = -1.02924e+96, cumulative = -1.02924e+96
ExecutionTime = 1.34 s ClockTime = 2 s

End


I get the time directories: 0 0.1 0.2 0.3 0.4 0.5 constant system VTK

However when i tried to execute foamToVTK to see the results in Paraview I get error messages.

/*---------------------------------------------------------------------------*\
| ========= | |
| \ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \ / O peration | Version: 1.3 |
| \ / A nd | Web: http://www.openfoam.org |
| \/ M anipulation | |
\*---------------------------------------------------------------------------*/

Exec : foamToVTK . pipe
Date : Sep 22 2006
Time : 12:31:50
Host : bro835a-cm
PID : 8753
Root : /home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam
Case : pipe
Nprocs : 1
Create time

Deleting old VTK files in "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/ pipe/VTK"

Time constant
volScalarFields :
volVectorFields :
pointScalarFields :
pointVectorFields :

Internal : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/p ipe_0.vtk"
Original cells:500 points:1212 Additional cells:0 additional points:0

Patch : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/O UTLET/OUTLET_0.vtk"
Patch : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/C ENTERLINE/CENTERLINE_0.vtk"
Patch : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/W ALL/WALL_0.vtk"
Patch : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/I NLET/INLET_0.vtk"
Patch : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/f rontAndBackPlanes/frontAndBackPlanes_0.vtk"
Time 0
volScalarFields : p
volVectorFields : U
pointScalarFields :
pointVectorFields :

Internal : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/p ipe_1.vtk"
Patch : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/O UTLET/OUTLET_1.vtk"
Patch : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/C ENTERLINE/CENTERLINE_1.vtk"
Patch : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/W ALL/WALL_1.vtk"
Patch : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/I NLET/INLET_1.vtk"
Patch : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/f rontAndBackPlanes/frontAndBackPlanes_1.vtk"
Time 0.1
volScalarFields : p
volVectorFields : U
pointScalarFields :
pointVectorFields :

Internal : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/p ipe_2.vtk"
Patch : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/O UTLET/OUTLET_2.vtk"
Patch : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/C ENTERLINE/CENTERLINE_2.vtk"
Patch : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/W ALL/WALL_2.vtk"
Patch : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/I NLET/INLET_2.vtk"
Patch : "/home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/VTK/f rontAndBackPlanes/frontAndBackPlanes_2.vtk"
Time 0.2
volScalarFields : p


--> FOAM FATAL IO ERROR : wrong token type - expected Scalar found on line 31 th e word 'nan'

file: /home/li077/OpenFOAM/li077-1.3/run/tutorials/icoFoam/pipe/0.2/U at line 31 .

From function operator>>(Istream&, Scalar&)
in file /home/dm2/henry/OpenFOAM/OpenFOAM-1.3/src/OpenFOAM/lnInclude/Scalar. C at line 85.

FOAM exiting
Here is the contents of VTK folder

CENTERLINE frontAndBackPlanes INLET OUTLET pipe_0.vtk pipe_1.vtk pipe_2.vtk WALL

SHuo

aurelia September 22, 2006 01:57

Hello It blows up, look at yo
 
Hello
It blows up, look at your courant numbers:

Mean and max Courant Numbers = 4.1213e+77 1.56978e+79

VtK can't convert your files because there is "nan" in these files, wich means that you have something wrong going on in your computation
You should have some nonorthogonal corrector if your geometry is a pipe

Aurelia

atzaru September 22, 2006 02:28

Hi, decrease the Co number
 
Hi,

decrease the Co number (in the tuorial you have a nice example on how to calculate the nedded time step)

If your problem is a steady state one u can go the simpleFoam solver

Atzaru


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