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how to decrease time step based on previous result in openfoam

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Old   September 25, 2013, 06:35
Default how to decrease time step based on previous result in openfoam
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Yu CAO
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Hi
how to decrease time step based on previous result in openfoam? for example, at first, I set deltaT=0.1, and runed to 10, then I want to change deltaT to 0.01, and begin from time 10, what should I do? I changed the deltaT to 0.01 in system/controlDIC, but find it just ran 10 times 10.01,not from 10.01 to 10.10. Is that correct? What should I do?
Thank.
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Old   September 25, 2013, 07:31
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It seems because of time precision. I am wondering if there are any files except the uniform/time in the output folder would record time precision? I successfully change the deltaT in the same folder, but failed to do so by cp previous result from another folder. I am not sure the reason.
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Old   September 26, 2013, 05:21
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Joachim Herb
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Please post your system/controlDict. The relevant parameters are startFrom, startTime, stopAt, endTime, deltaT, writeControl and writeInterval. Perhaps also adjustTimeStep.
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Old   September 26, 2013, 07:34
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Quote:
Originally Posted by jherb View Post
Please post your system/controlDict. The relevant parameters are startFrom, startTime, stopAt, endTime, deltaT, writeControl and writeInterval. Perhaps also adjustTimeStep.
startFrom latestTime;
startTime 0.0;
stopAt endTime;
endTime 2000.0;
deltaT 0.00001;
writeControl runTime;
writeInterval 10;
cycleWrite 1;
writeFormat ascii;
writeCompression uncompressed;
timeFormat general;
timePrecision 8;
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Old   September 26, 2013, 18:17
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I do not know what cycleWrite means. Otherwise you might want to start from the tutorials, e.g. simpleFoam/motorBike:
Code:
startFrom       latestTime;
startTime 0.0;
stopAt          endTime;
endTime 10.1;
deltaT 0.01;
writeControl    timeStep;
writeInterval   1;
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Old   September 27, 2013, 17:56
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Quote:
Originally Posted by jherb View Post
I do not know what cycleWrite means. Otherwise you might want to start from the tutorials, e.g. simpleFoam/motorBike:
Code:
startFrom       latestTime;
startTime 0.0;
stopAt          endTime;
endTime 10.1;
deltaT 0.01;
writeControl    timeStep;
writeInterval   1;
Have you tried before?
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