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SI engine tutorial error non-positive volumes

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Old   March 24, 2010, 14:49
Default SI engine tutorial error non-positive volumes
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While going through the SI engine tutorial I encounter an error when trying to preview the mesh. At around crank angle 570 an error comes up mentioning the negative volume and cuts the preview. When I run the check mesh, it comes up with a couple warnings....

Volume statistics:
Warning: non-positive volumes exist.
minimum volume (m3): -5.334022e-022
maximum volume (m3): 3.089859e-006
total volume (m3): 9.300594e-003

Checking face handedness.
WARNING: left-handed faces detected on zone 41: 3491 right-handed, 2 left-handed.
WARNING: left-handed faces detected on zone 29: 5 right-handed, 2 left-handed.


I followed the tutorial as close as I could up to that point and am not sure where the problem may be from.

The tutorial can be downloaded from this location
http://www.fluent.com/software/sf_me..._si_engine.htm

Thank you

__________________________________________________ ________________________________________________

EDIT: In the transition from the Fluent 6 tutorial to Fluent 12 I missed a simple step that wasn't clear and that was checking the region face box in the remeshing methods option

Last edited by rackem; March 24, 2010 at 15:32.
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Old   March 28, 2010, 23:25
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I meet the same problem...maybe we should try little time steps,for example set the Crank Angle Time Step to 0.1 in dynamic mesh parameters\in cylinder
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Old   March 31, 2010, 15:08
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were you able to run this correctly? I run into problems when the simulation starts the spray injection and the program freezes.
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Old   March 31, 2010, 22:40
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I found it unable to process whe start mesh motion in order to preview the dynamic mesh. it appears negetive volume
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Old   March 31, 2010, 23:06
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I fixed this by checking the region face box in the remeshing methods options in the dynamic mesh settings.
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Old   April 2, 2010, 23:19
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Quote:
Originally Posted by rackem View Post
were you able to run this correctly? I run into problems when the simulation starts the spray injection and the program freezes.
hi:
I follow all the tutorial tell me to do.but I found the same problem when the simulation starts the spray and the program freeze.did you find how to solve it?

thanks in advance
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Old   April 7, 2010, 19:19
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No I have not found a way around this
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Old   April 8, 2010, 21:23
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Quote:
Originally Posted by rackem View Post
No I have not found a way around this
hi rackem:
when I disable "track with fluid flow time step" in define->model->discrete phase->particle treatment,the simulation go down to the end.
have a try,hope it help
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Old   April 9, 2010, 12:25
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My solution still stops at injection. What does your discrete phase model look like. Right now I have Interaction with Continuous Phase and Update DPM Sources Every Flow Iteration checked in the Interaction box. (Note I can't change the Number of Continuous Phase Iterations per DPM Iteration to 5 as it is grayed out and has to be 200) In Particle Treatment I have Unsteady Particle Tracking checked and the Particle Time Step Size (s) at 0.001 (Note the Number of Time Steps is grayed out and listed at 1). In Inject Particles at I have Particle Time Step selected instead of Fluid Flow Time Step. In Physical Models I have Droplet Collision and Droplet Breakup selected in the Spray Model. TAB as the Breakup Model. y0=0 and 2 Breakup Parcels in Breakup Constants.

Thanks for the help!
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Old   April 9, 2010, 21:32
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Quote:
Originally Posted by rackem View Post
My solution still stops at injection. What does your discrete phase model look like. Right now I have Interaction with Continuous Phase and Update DPM Sources Every Flow Iteration checked in the Interaction box. (Note I can't change the Number of Continuous Phase Iterations per DPM Iteration to 5 as it is grayed out and has to be 200) In Particle Treatment I have Unsteady Particle Tracking checked and the Particle Time Step Size (s) at 0.001 (Note the Number of Time Steps is grayed out and listed at 1). In Inject Particles at I have Particle Time Step selected instead of Fluid Flow Time Step. In Physical Models I have Droplet Collision and Droplet Breakup selected in the Spray Model. TAB as the Breakup Model. y0=0 and 2 Breakup Parcels in Breakup Constants.

Thanks for the help!
hi
here is my panel.
obey all the process tutorial tells us to do.
try!
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Old   April 14, 2010, 17:14
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I've obeyed all the processes, but still get it freezes at injection. You do not follow the tutorial because you do not have "Update DPM Sources Every Flow Iteration" checked per your image that you posted. So I'm not sure which rules to follow in the tutorial.

What do you have checked in the "physical models" tab in the Discrete Phase Model?

When I check Droplet Collision in the Discrete Phase Model/Physical Models tab it changes my "Number of Continuous Phase Iterations per DPM Iteration" back to 200 and grays it out.

What version of Fluent are you using? I'm using 12.0.1
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Old   April 14, 2010, 20:07
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Quote:
Originally Posted by rackem View Post
I've obeyed all the processes, but still get it freezes at injection. You do not follow the tutorial because you do not have "Update DPM Sources Every Flow Iteration" checked per your image that you posted. So I'm not sure which rules to follow in the tutorial.

What do you have checked in the "physical models" tab in the Discrete Phase Model?

When I check Droplet Collision in the Discrete Phase Model/Physical Models tab it changes my "Number of Continuous Phase Iterations per DPM Iteration" back to 200 and grays it out.

What version of Fluent are you using? I'm using 12.0.1
my version is 6.2.26
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Old   November 22, 2010, 08:06
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Is there any solution ?
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