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Starting turbulence models later after a few hundred iterations. |
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October 12, 2011, 03:56 |
Starting turbulence models later after a few hundred iterations.
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#1 |
Member
Hamza Motiwala
Join Date: Nov 2010
Posts: 41
Rep Power: 15 |
Hey everyone,
Is there a way to turn on the turbulence models automatically after a few 100 iterations? Its something similar to turning on a Heat Exchanger model (if you are familiar with it). Is it possible in someway with the help of field functions or something? Thanks, Hamza |
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October 13, 2011, 17:59 |
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#2 |
Senior Member
Join Date: Oct 2009
Location: Germany
Posts: 636
Rep Power: 21 |
No, to turn on the model, you have to stop the simulation, therefore you can't do it with a field function.
What you can do is to record a java macro and adjust the number of iterations before switching on the turbulence model. |
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October 25, 2011, 09:50 |
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#3 |
Member
Hamza Motiwala
Join Date: Nov 2010
Posts: 41
Rep Power: 15 |
hey abdul,
thanks for the idea...but doesnt recording the macro mean that i need to make a recording upto that many iterations? and is it automatic, i mean the recording..does the recording turn on and off on its own if i send the simulation to the cluster? because to run the simulation locally would take some time even for just a few 100 iterations.... |
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October 25, 2011, 10:00 |
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#4 | |
Senior Member
Ryne Whitehill
Join Date: Aug 2009
Posts: 312
Rep Power: 18 |
Quote:
You can then submit the job to the cluster using the script |
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October 25, 2011, 10:10 |
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#5 |
Member
Hamza Motiwala
Join Date: Nov 2010
Posts: 41
Rep Power: 15 |
Thanks Ryne,
Will try that out and get back to you..since I have never done something like this before...I might need assistance... |
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October 25, 2011, 20:32 |
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#6 |
Senior Member
Join Date: Oct 2009
Location: Germany
Posts: 636
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Just record a macro and run the simulation for let's say 5 steps, and then switch on the turbulence model. Than have a look at the macro. There will be somewhere a line containing either the number of steps until you stopped the simulation or just a run(); command. Don't know without looking it up. Just modify this line, by either changing the number or when there's the run-command, change it to run(500); or which number of iterations you want before switching on the turbulence mode.
To run it on the cluster, you just have to submit your job with the macro. There's the -batch command line option. Just add the path to your macro directly after the -batch, e.g. -batch turbulencemodelstartmacro.java |
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October 28, 2011, 05:16 |
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#7 |
Member
Hamza Motiwala
Join Date: Nov 2010
Posts: 41
Rep Power: 15 |
Hey guys,
I tired recording a macro and then modifying it but there was no information about the iterations when the turbulence model was turned on and off. Its just something like turnturbulenceon(false/true).. Ryne when you said that I need to add logic to the code, did you mean I should write my own code to detect the iterations? because I couldnt find any numbers in the code denoting the iterations. |
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October 28, 2011, 09:51 |
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#8 | |
Senior Member
Ryne Whitehill
Join Date: Aug 2009
Posts: 312
Rep Power: 18 |
Quote:
A simpler method would be what abdul recommended: Run(500 iterations) |
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November 29, 2011, 13:53 |
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#9 |
New Member
Harsh Shah
Join Date: Jul 2011
Posts: 4
Rep Power: 14 |
Under the solvers, ramp up the turbulence model URF and keep initial value to zero and define start iteration to 100 and probably can define end iteration to 200 or so.
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December 7, 2011, 09:53 |
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#10 |
Member
Hamza Motiwala
Join Date: Nov 2010
Posts: 41
Rep Power: 15 |
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December 7, 2011, 11:40 |
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#11 |
New Member
Harsh Shah
Join Date: Jul 2011
Posts: 4
Rep Power: 14 |
As long as URF value for turbulence is zero, the value of turbulence variables (depends on turbulence model) wan't be updated (remains constant as of initial values). Even though it is different from freezing the solver, it works in most of the cases.
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December 9, 2011, 05:25 |
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#12 |
Member
Hamza Motiwala
Join Date: Nov 2010
Posts: 41
Rep Power: 15 |
Ok. I asked because I thought URF usually decides how much percentage of the previous iteration it takes to calculate the new step and setting the value to 0 would mean that I would be calculating the turbulence value for every iteration from scratch all the time. or am I completely wrong here about URFs?
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