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Old   July 17, 2010, 06:36
Default efficiency of rotating helix
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s Kumar
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Hi everyone.

I have helix (stl)in fluid. It is given prescribed rotational motion. Due to this it gets coupled tranlational motion along axis. I want to know how much time or how many rotations needed to move the helix its one complete length( a measure of efficiency). I have to repeat this various configuration. I have all stl files. when run it takes so much time, and I am struck in between. |Plz some one help me.

Last edited by doctsh; July 17, 2010 at 06:58.
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Old   July 29, 2010, 03:26
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seem like your mesh count is huge and running with serial license?
try to remove the fluid and inspect how long does it take to run the simulation.
or reduce mesh count to speed up simulation if possible, last option is to consider SMP/MPI for parallel processing. Hope this help.
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Old   July 29, 2010, 06:04
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Thanks a lot. I am trying your suggestions now..
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Old   August 1, 2010, 10:18
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s Kumar
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Hi, as per your advice I did remove the fluid and ran. The calculation was over after 10 min and i didnot see any motion of stl.

I am running parallel 2-processors.

The mesh info is attached as screen shot.

I dont know my meshing is correct or not. As i expected a cork-screw like motion along y-axis i gave some space, i dont know it is correct or not.

Would you please advice me what kind of meshing i should choose for observing linear motion of one length of helix.
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File Type: jpg mesh.jpg (16.1 KB, 17 views)
File Type: jpg mesh info.jpg (39.5 KB, 20 views)
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Old   August 2, 2010, 23:35
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guess that your mesh size might be larger than your geometry size. This cause you object is actually not mesh properly and not consider in the solution.
you can check by click on FAVOR button to ensure you see solid object for the model. Alternatively you can check in in post-processing and plot to ensure the solid object is mesh.
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Old   August 6, 2010, 00:59
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s Kumar
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Hi, I did them but no use.

My doubt is as helix is moving forward, should i have to draw mesh with empty space to give space for moving and observe? or I can just use 'fit to geometry' mesh?

thanks in advance
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Old   August 9, 2010, 01:09
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Hi Kumar
what is your helix diameter size and what is your minimum mesh size? your minimum mesh size should be few magnitude smaller than your helix diameter size. pls check it out.
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Old   August 10, 2010, 03:16
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Hi grace01,

would you please tell me what you tried? how you know its working? please share it I am struggling for long time...
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