# Rigid Body motion??

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 April 25, 2013, 04:54 Rigid Body motion?? #1 Member   Arun Krishnan.L.H Join Date: Jan 2013 Posts: 74 Rep Power: 4 Dear All, I have done the boat tutorial and followed the same procedure to define DFBI for a cylinder on free surface. The fluid domain is 40x10x3 and origin of the cylinder is at 0,0. Free surface is also initialised at 0,0. Can I impart simple harmonic oscillations to the cylinder using a field function and reference the field in the initial velocity tab of DFBI? When i do it the whole domain seems to be moving. It was done successfully using translation, morphing and overset mesh. I also tried to define a wave at the inlet to see the free motion of the cylinder. Again the whole domain was moving. I have created a new cartesian coordinate at 0,0 which is referenced in initial coordinate of DFBI. Can you please give me suggestions. ? Regards Arun

 April 27, 2013, 11:15 #2 Senior Member   KHB Join Date: Aug 2010 Location: Singapore Posts: 107 Rep Power: 6 I might not get your question. But if you can perform successfully with morphing/overset, then you can do the same when there is wave right? If no morphing/overset then I believe the whole domain will move since the mesh is fixed w.r.t. the cylinder.

April 27, 2013, 12:30
#3
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Arun Krishnan.L.H
Join Date: Jan 2013
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Quote:
 Originally Posted by lava12005 I might not get your question. But if you can perform successfully with morphing/overset, then you can do the same when there is wave right? If no morphing/overset then I believe the whole domain will move since the mesh is fixed w.r.t. the cylinder.
Thanks a lot Lava. I was also thinking the same. Tried every possible thing i could. I thought this would work just like the boat tutorial. There the mesh is fixed to the boat, but when we it experiences an encountering wave, it heave and pitches.

I am going to a seminar by CD-adapco on tuesday will clear the doubts with them. If you have time please could you check my thread 'hydrodynamic force?' which was posted a few days back. If you have any idea could you please give me some help.

Thanks
Regards
Arun

 April 30, 2013, 02:45 star ccm+ #4 New Member   yanbin Join Date: Apr 2013 Posts: 15 Rep Power: 4 I have met the same problem. The whole domain will be moving with the DFBI module. I have been trouble for this question for two weeks.

 April 30, 2013, 02:47 #5 New Member   yanbin Join Date: Apr 2013 Posts: 15 Rep Power: 4 how can I check the mesh is fixed w.r.t. the cylinder? When generating the volume mesh, the cylinder and whole domain are meshing at the same time.

 April 30, 2013, 03:39 #6 Senior Member   KHB Join Date: Aug 2010 Location: Singapore Posts: 107 Rep Power: 6 Hi Yanbin, If you are not using any Overset or morphing mesh, then the whole mesh will be fixed, it means the whole domain will move with the cylinder. Depending on what you want to achieve this is still fine (example the boat tutorial domain is moving with the boat). You just need to be careful regarding the mesh resolution at the boundary (say the free surface resolution getting worse due to the moving boundary). There are overset and morphing tutorial, so you can see their difference. Good luck!

April 30, 2013, 03:48
#7
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yanbin
Join Date: Apr 2013
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Quote:
 Originally Posted by lava12005 Hi Yanbin, If you are not using any Overset or morphing mesh, then the whole mesh will be fixed, it means the whole domain will move with the cylinder. Depending on what you want to achieve this is still fine (example the boat tutorial domain is moving with the boat). You just need to be careful regarding the mesh resolution at the boundary (say the free surface resolution getting worse due to the moving boundary). There are overset and morphing tutorial, so you can see their difference. Good luck!
Thanks for your advice！I'll try and I will consult you if there are other problems.

 June 4, 2013, 01:11 a fatal error has been detected by the Java Runtime Environment. #8 New Member   yanbin Join Date: Apr 2013 Posts: 15 Rep Power: 4 Hello. I have met a problem that the star ccm+ program exited during the running and a notepad file produced. It shows that a fatal error has been detected by the Java Runtime Environment. What's wrong with my operation for the star ccm+ program? Can you help me?

 June 4, 2013, 04:31 #9 Member   Arun Krishnan.L.H Join Date: Jan 2013 Posts: 74 Rep Power: 4 Do you have any msgs in your output window? Could you please elaborate a little? your problem and how you set it. Thanks Regards Arun

 June 13, 2013, 03:37 #10 New Member   yanbin Join Date: Apr 2013 Posts: 15 Rep Power: 4 I'm so sorry for being late. There is a log file named "hs_err_pid720.log". The main point of the log file is listed below, # A fatal error has been detected by the Java Runtime Environment: # # EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x000007feed0e98af, pid=720, tid=1948 # # JRE version: 6.0_35-b10 # Java VM: Java HotSpot(TM) 64-Bit Server VM (20.10-b01 mixed mode windows-amd64 compressed oops) # Problematic frame: # C [vtkCommon.dll+0x498af] # # If you would like to submit a bug report, please visit: # http://java.sun.com/webapps/bugreport/crash.jsp # The crash happened outside the Java Virtual Machine in native code. # See problematic frame for where to report the bug. Thanks for help

July 9, 2013, 09:05
zero acceptor cells in overset region
#11
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yanbin
Join Date: Apr 2013
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Hi,
Have you met the problem "zero acceptor cells in overset region" ?

Yan Bin

Quote:
 Originally Posted by arun7328 Do you have any msgs in your output window? Could you please elaborate a little? your problem and how you set it. Thanks Regards Arun

 July 9, 2013, 09:44 #12 Senior Member   KHB Join Date: Aug 2010 Location: Singapore Posts: 107 Rep Power: 6 Maybe your overset mesh has a low resolution somewhere and they meet with a high background mesh resolution? The overset and background mesh should have similar mesh size around the intersection area..

July 9, 2013, 23:45
zero acceptor cells in overset region
#13
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yanbin
Join Date: Apr 2013
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Quote:
 Originally Posted by lava12005 Maybe your overset mesh has a low resolution somewhere and they meet with a high background mesh resolution? The overset and background mesh should have similar mesh size around the intersection area..

November 13, 2013, 10:15
#14
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MB
Join Date: Sep 2012
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Quote:
 Originally Posted by yanbin Thank you for your advice! I am trying!

Did you solve it? I´m facing the same problem here...!

November 14, 2013, 00:42
#15
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yanbin
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Quote:
 Originally Posted by matzbanni Did you solve it? I´m facing the same problem here...!
Yes, I have solved the problem by the advice of lava12005!

 November 14, 2013, 03:19 #16 New Member   MB Join Date: Sep 2012 Posts: 22 Rep Power: 4 Found the problem as well, but it wasn't a resolution issue...

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