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-   -   simulation not completed in HPDC (thin wall casting) (http://www.cfd-online.com/Forums/flow-3d/71693-simulation-not-completed-hpdc-thin-wall-casting.html)

flyingming January 12, 2010 08:15

simulation not completed in HPDC (thin wall casting)
 
hi,
recently, i had simulated some thin wall castings, but always can not be simulated completed.
in flow3d--simulate--,i can see solver 100%,and the terminated time was 0.02s for example, but in flow 3d--analyze,the time frame just 0,013(restart and spatial data available at t= 1.3e-2). so when i render the result,it just display the time from 0 to 0.013, not 0 to 0.02.

below are two erro messages:
a:
Solver Messages:


============= mentor tip ===============
persistent f-packing location at t= 0.16605E-02
x= 0.36856E+01, y= 0.39625E+01, z= 0.34898E+01
i= 160, j= 160, k= 21
f= 0.30552E+00
recommend reducing cfpk by factor of 10
========================================






end of calculation at t= 7.558E-03 cycle = 16509
terminated by operator

elapsed time (seconds) = 4.413E+04
cpu= 7.754E+04

b:Solver Messages:
convective flux exceeded stability limit
at t= 3.2542E-04 cycle= 27 iter= 1 delt= 1.1767E-05 mesh block 1
restarting cycle with smaller time step



convection failure diagnostics
time, cycle, delt, iter = 3.2542E-04 27 1.1767E-05 1
maximum failure ratio = 1.51784E+00 is in x-coordinate direction
at cell ( 12, 2, 217) mesh block 1





convective flux exceeded stability limit
at t= 3.8074E-03 cycle= 1008 iter= 8 delt= 2.7749E-06 mesh block 1
restarting cycle with smaller time step



convection failure diagnostics
time, cycle, delt, iter = 3.8074E-03 1008 2.7749E-06 8
maximum failure ratio = 1.74792E+00 is in x-coordinate direction
at cell ( 22, 13, 190) mesh block 1





convective flux exceeded stability limit
at t= 1.0472E-02 cycle= 3219 iter= 6 delt= 3.1770E-06 mesh block 1
restarting cycle with smaller time step



convection failure diagnostics
time, cycle, delt, iter = 1.0472E-02 3219 3.1770E-06 6
maximum failure ratio = 1.09198E+00 is in x-coordinate direction
at cell ( 127, 15, 43) mesh block 1





convective flux exceeded stability limit
at t= 1.6698E-02 cycle= 6248 iter= 4 delt= 2.6722E-06 mesh block 1
restarting cycle with smaller time step



convection failure diagnostics
time, cycle, delt, iter = 1.6698E-02 6248 2.6722E-06 4
maximum failure ratio = 1.20080E+00 is in y-coordinate direction
at cell ( 98, 32, 161) mesh block 1





convective flux exceeded stability limit
at t= 1.7523E-02 cycle= 6579 iter= 5 delt= 2.5634E-06 mesh block 1
restarting cycle with smaller time step



convection failure diagnostics
time, cycle, delt, iter = 1.7523E-02 6579 2.5634E-06 5
maximum failure ratio = 1.22621E+00 is in y-coordinate direction
at cell ( 59, 29, 258) mesh block 1

i j k u v w p f nf
afr afb aft vf

59, 29, 257 -1.9432E+03 -2.1359E+03 4.5292E+03 1.0130E+06 8.6285E-01
(old) -1.9000E+03 -2.4249E+03 4.9746E+03 1.0130E+06 5.9903E-01 5
6.7095E-02 1.0000E+00 1.2971E-01 3.2258E-01
59, 28, 258 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
(old) 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0
0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
58, 29, 258 9.8101E+02 1.0632E+02 3.8510E+02 1.0128E+06 2.1497E-01
(old) 8.8445E+02 1.3217E+02 3.7555E+02 1.0128E+06 1.9972E-01 1
1.9228E-01 1.0000E+00 2.6050E-01 3.2258E-01
59, 29, 258 -7.0077E+02 -9.8304E+03 0.0000E+00 1.0130E+06 1.4258E-01
(old) -7.1534E+02 -1.0659E+04 0.0000E+00 1.0130E+06 0.0000E+00 87
6.7362E-02 1.0000E+00 1.2994E-01 3.2258E-01
60, 29, 258 0.0000E+00 -1.9648E+03 4.7150E+03 1.0130E+06 7.7120E-01
(old) 0.0000E+00 -2.0059E+03 5.4562E+03 1.0130E+06 5.6331E-01 5
0.0000E+00 5.7495E-01 1.9459E-02 1.8547E-01
59, 30, 258 -1.9454E+03 -1.0227E+03 -2.1307E+03 1.0130E+06 9.3722E-01
(old) -2.0083E+03 -1.0392E+03 -2.5703E+03 1.0130E+06 7.2170E-01 4
1.0000E+00 1.0000E+00 1.0000E+00 1.0000E+00
59, 29, 259 0.0000E+00 -3.4946E+03 -7.4806E+02 1.0130E+06 0.0000E+00
(old) 0.0000E+00 -3.2465E+03 -6.1546E+02 1.0130E+06 0.0000E+00 87
6.7688E-02 1.0000E+00 1.3018E-01 3.2258E-01





end of calculation at t= 2.068E-02 cycle = 8616
no accessible empty cells

elapsed time (seconds) = 1.767E+04
cpu= 3.470E+04

someone can help me to resolve the problems, many thanks!

MuxaB January 13, 2010 10:17

It looks like in case b it ran to completion since the final message is 'there are no accessible empty cells', no?

The error messages you see are not fatal as long as they are occasional. They are common in such complex simulations.

Do you see the die full at t=0.013 seconds? You can define a more frequent output for the restart data to see more dynamics, or use the selected data output.

flyingming January 13, 2010 23:42

hi MuxaB,
i maybe explain not clearly of the issue, as your said in case b, it ran to completion,but the result show the casting just filled not 100%. just what i said ,fill completed need 0.02s, simulation was stop at 0.02s,but the display only show fill to 0.13s.

maybe the error messages are not fatal, but i can just analyze from the error messages. in anther casting ,i tried to reduce the minium time step,
it can simulate completede, and fill completed. however ,in others casting ,i also reduced the minium time step , and the error message just prompted one error "Pressure iteration did not converge in Itmax = IMAX," just like case b.

i will try to use the restart fuction .

i think the mesh and the convergence interation are the main reasons to influen the simulation result.

MuxaB January 20, 2010 12:24

Quote:

Originally Posted by flyingming (Post 242511)
hi MuxaB,
i maybe explain not clearly of the issue, as your said in case b, it ran to completion,but the result show the casting just filled not 100%. just what i said ,fill completed need 0.02s, simulation was stop at 0.02s,but the display only show fill to 0.13s.

maybe the error messages are not fatal, but i can just analyze from the error messages. in anther casting ,i tried to reduce the minium time step,
it can simulate completede, and fill completed. however ,in others casting ,i also reduced the minium time step , and the error message just prompted one error "Pressure iteration did not converge in Itmax = IMAX," just like case b.

i will try to use the restart fuction .

i think the mesh and the convergence interation are the main reasons to influen the simulation result.

Try this:

Go to the directory where you ran the problem and delete the files starting with g_flsgrf, c_flsgrf and t_flsgrf and flsg000. These are temporary files created by the solver and post-processor to help quickly navigate around the output file flsgrf. Sometimes they become out of sinc with the file and makes parts of it inaccessible.

After deleting them, reopen the flsgrf results file in the GUI. The temporary files will be recreated, but it will take a little time.


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