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-   -   A basic doubt on reading the iteration results (http://www.cfd-online.com/Forums/openfoam-post-processing/61376-basic-doubt-reading-iteration-results.html)

hariya03 July 16, 2008 08:28

Dear Mr.Tammo, Thank you ve
 
Dear Mr.Tammo,

Thank you very much for your reply.

I did it with uniform conditions itself.

I had seen user guide for many of my doubts. Its very brief as I look in OpenFOAM site.

I need another one basic clarification to know how to read the iteration results and what does the residuals actually mean.

We are calculating the flow rate of a valve.

In inlet 7000 Pa is given and outlet is 0Pa and we fixed outlet pressurised condition to both inlet and outlet.

after running the simple foam i am getting these results.


Time = 1

DILUPBiCG: Solving for Ux, Initial residual = 1, Final residual = 1.49213e-05, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for Uz, Initial residual = 0, Final residual = 0, No Iterations 0
GAMG: Solving for p, Initial residual = 1, Final residual = 0.000601879, No Iterations 6
time step continuity errors : sum local = 2.18714, global = -0.0619567, cumulative = -0.0619567
DILUPBiCG: Solving for epsilon, Initial residual = 0.897335, Final residual = 1.02147e-05, No Iterations 1
DILUPBiCG: Solving for k, Initial residual = 1, Final residual = 1.38556e-05, No Iterations 1
ExecutionTime = 0.77 s ClockTime = 1 s

Time = 2

DILUPBiCG: Solving for Ux, Initial residual = 0.00335051, Final residual = 4.38432e-08, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.00397104, Final residual = 4.84344e-08, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.00331844, Final residual = 4.17761e-08, No Iterations 1
GAMG: Solving for p, Initial residual = 0.943068, Final residual = 0.000466685, No Iterations 14
time step continuity errors : sum local = 0.500458, global = -0.060284, cumulative = -0.122241
DILUPBiCG: Solving for epsilon, Initial residual = 0.862161, Final residual = 1.21649e-05, No Iterations 1
DILUPBiCG: Solving for k, Initial residual = 0.842201, Final residual = 1.88649e-05, No Iterations 1
ExecutionTime = 1.24 s ClockTime = 1 s

Time = 3

DILUPBiCG: Solving for Ux, Initial residual = 0.147196, Final residual = 2.8822e-06, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.112165, Final residual = 1.96374e-06, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.138183, Final residual = 2.76485e-06, No Iterations 1
GAMG: Solving for p, Initial residual = 0.631318, Final residual = 0.000284522, No Iterations 6
time step continuity errors : sum local = 2.06408, global = -0.124974, cumulative = -0.247215
DILUPBiCG: Solving for epsilon, Initial residual = 0.863321, Final residual = 1.39978e-05, No Iterations 1
DILUPBiCG: Solving for k, Initial residual = 0.813142, Final residual = 2.10478e-05, No Iterations 1
ExecutionTime = 1.62 s ClockTime = 1 s


I did the iteration to 300 time and input the 300 time to 0th time,

Could you educate me about the basic questions below?
what does this paragraph mean?

What to calculate actually from this paragraph?

What for the residuals stand and how to interpret the values from it?


I could not found out the details in users manual.

it would be helpful for me if you advice the regard.

Thank you

V.Hari


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