LB_K |
December 10, 2011 11:24 |
Divergence in simpleFoam
1 Attachment(s)
Hello everyone.
I am a newbie in OpenFoam, so don't be too strict to me. I have a task to calculate the steady state pressure and velocity field in cylinder with 2 cylinder holes - one of them inlet, and another one is outlet. The inlet velocity in known.
I tried to use icoFoam, but after a lot of calculation steps the courant number went very high and the solution diverged. So, i changed solver to simpleFoam.
Some information about how to use simpleFoam i've got from http://www.cfd-online.com/Forums/ope...am-solver.html
Simplefoam looks to work well, but starting from the 300th step something strange happens.
Quote:
Time = 301
smoothSolver: Solving for Ux, Initial residual = 0.00451893, Final residual = 4.43897e-05, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 0.0046188, Final residual = 4.43219e-05, No Iterations 2
smoothSolver: Solving for Uz, Initial residual = 0.00303527, Final residual = 2.93432e-05, No Iterations 2
GAMG: Solving for p, Initial residual = 0.141931, Final residual = 9.16397e-05, No Iterations 5
GAMG: Solving for p, Initial residual = 0.0308181, Final residual = 1.08156e-05, No Iterations 5
GAMG: Solving for p, Initial residual = 0.0111861, Final residual = 8.45965e-06, No Iterations 5
GAMG: Solving for p, Initial residual = 0.00815672, Final residual = 3.46598e-06, No Iterations 6
time step continuity errors : sum local = 6.31434e-06, global = 2.92482e-09, cumulative = 7.47596e-06
ExecutionTime = 2063.25 s ClockTime = 2110 s
Time = 302
smoothSolver: Solving for Ux, Initial residual = 0.00451987, Final residual = 4.44502e-05, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 0.00461933, Final residual = 4.42789e-05, No Iterations 2
smoothSolver: Solving for Uz, Initial residual = 0.00303333, Final residual = 2.93334e-05, No Iterations 2
GAMG: Solving for p, Initial residual = 0.143248, Final residual = 8.37238e-05, No Iterations 5
GAMG: Solving for p, Initial residual = 0.0304607, Final residual = 2.76634e+08, No Iterations 100
GAMG: Solving for p, Initial residual = 0.386885, Final residual = 5.57401e+12, No Iterations 100
GAMG: Solving for p, Initial residual = 0.386885, Final residual = 5.57401e+12, No Iterations 100
time step continuity errors : sum local = 4.2355e+34, global = 7.5829e+29, cumulative = 7.5829e+29
ExecutionTime = 2147.48 s ClockTime = 2212 s
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Geometry -
http://www.cfd-online.com/Forums/mem...1-geometry.png
Mesh information -
Quote:
Mesh stats
points: 33093
faces: 344465
internal faces: 325947
cells: 167603
boundary patches: 3
point zones: 0
face zones: 0
cell zones: 1
Overall number of cells of each type:
hexahedra: 0
prisms: 0
wedges: 0
pyramids: 0
tet wedges: 0
tetrahedra: 167603
polyhedra: 0
Checking topology...
Boundary definition OK.
Cell to face addressing OK.
Point usage OK.
Upper triangular ordering OK.
Face vertices OK.
Topological cell zip-up check OK.
Face-face connectivity OK.
Number of regions: 1 (OK).
Checking patch topology for multiply connected surfaces ...
Patch Faces Points Surface topology Bounding box
wall 9810 5533 ok (non-closed singly connected) (-5 -5 0) (5 5 5)
inlet 4354 2492 ok (non-closed singly connected) (2 -1 2) (4 1 2)
outlet 4354 2492 ok (non-closed singly connected) (-4 -1 2) (-2 1 2)
Checking geometry...
Overall domain bounding box (-5 -5 0) (5 5 5)
Mesh (non-empty, non-wedge) directions (1 1 1)
Mesh (non-empty) directions (1 1 1)
Boundary openness (4.74506e-17 7.24893e-20 1.1664e-16) OK.
Max cell openness = 2.50855e-16 OK.
Max aspect ratio = 4.59859 OK.
Minumum face area = 2.60582e-05. Maximum face area = 1.33205. Face area magnitudes OK.
Min volume = 8.06256e-08. Max volume = 0.49308. Total volume = 377.31. Cell volumes OK.
Mesh non-orthogonality Max: 51.5241 average: 15.8802
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 0.87808 OK.
Coupled point location match (average 0) OK.
Face tets OK.
Min/max edge length = 0.00677553 1.94168 OK.
All angles in faces OK.
All face flatness OK.
Cell determinant (wellposedness) : minimum: 0.0209264 average: 1.49098
Cell determinant check OK.
Concave cell check OK.
Mesh OK.
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I have not got any experience, so any help will be necessary to me.
Thanks.
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