# simulation of VIV for a cylinder

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 April 13, 2014, 04:45 simulation of VIV for a cylinder #1 New Member   Ma.L Join Date: May 2013 Location: ShangHai,China Posts: 17 Rep Power: 5 i want to simulate a VIV of a cylinder.when water pass through a cylinder,the cylinder will vibrate，so i would like to simulate this phenomenon with CFX by the method of FSI,i Look forward to cylindrical can shake up in the CFD-post. but i don't know how to make it,could you help me? thanks!

 April 13, 2014, 06:34 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 12,240 Rep Power: 96 FIrst of all - try to minimise the use of acronyms. It just makes it hard to read. For the record, VIV = vortex induced vibration, doesn't it? There are two methods to model this - entirely within CFX using the rigid body solver or coupled with ANSYS FEA. See the buoy example for an example of the rigid body solver approach. This approach is cimpler and nice, but cannot handle complex constraints. The ANSYS FEA approach can model just about anything but is more complex and slower. I cannot judge which approach is better with the information you have provided so far. You would need to describe what is holding the cylinder. bestniaz likes this.

 April 14, 2014, 13:27 #3 Senior Member   ok Join Date: Oct 2013 Posts: 338 Rep Power: 5 Dear Mal, these days, I'm looking exactly to the same case. I'm studying wingMotion in pimpleDyMFoam solver as a test case. The three directories in the wingMotion case are for (i) meshing -snappyHexMesh, (ii) steady solve initialisation - simple, (iii) the moving mesh transient solve -pimpleDyM. I'm still working to get the result. If you get any idea let help each other to reach the result. All the best.

 April 14, 2014, 13:29 #4 Senior Member   ok Join Date: Oct 2013 Posts: 338 Rep Power: 5 Dear Glenn, VIV =Vortex Induced Vibrations. Regards

April 18, 2014, 22:01
#5
New Member

Ma.L
Join Date: May 2013
Location: ShangHai,China
Posts: 17
Rep Power: 5
Quote:
 Originally Posted by Maimouna Dear Mal, these days, I'm looking exactly to the same case. I'm studying wingMotion in pimpleDyMFoam solver as a test case. The three directories in the wingMotion case are for (i) meshing -snappyHexMesh, (ii) steady solve initialisation - simple, (iii) the moving mesh transient solve -pimpleDyM. I'm still working to get the result. If you get any idea let help each other to reach the result. All the best.
Dear Maimouna，
I have found a method of fluid-structure interaction to solve this problem.u can use CFX together with transient structure in workbench.Structure setting is conducted in the transient structure, and u should name a domain interface used to transfer data,then u can write a "inp" file.Flow setting is conducted in the CFX,choose ANSYS MultiField in the external solver coupling,and then inport the "inp"file.The solving way should be the coupling solution in the solution control.

April 18, 2014, 22:16
#6
New Member

Ma.L
Join Date: May 2013
Location: ShangHai,China
Posts: 17
Rep Power: 5
Quote:
 Originally Posted by ghorrocks FIrst of all - try to minimise the use of acronyms. It just makes it hard to read. For the record, VIV = vortex induced vibration, doesn't it? There are two methods to model this - entirely within CFX using the rigid body solver or coupled with ANSYS FEA. See the buoy example for an example of the rigid body solver approach. This approach is cimpler and nice, but cannot handle complex constraints. The ANSYS FEA approach can model just about anything but is more complex and slower. I cannot judge which approach is better with the information you have provided so far. You would need to describe what is holding the cylinder.
Dear ghorrocks,
Thanks for you reply, you are right. VIV = vortex induced vibration.i have used the method of coupled with ANSYS FEA to solve my case.The cylinder is holded by a mechanical spring.Could you tell me what is meaning of the calculation curve in the solving procedure, including RMS and volecity and so on.I monitor the displacement of meshing and the force on cylinder in
calculation workspace ,but there are no units of them,so i just don't understand what these Numbers mean. Thank you again.

 April 19, 2014, 05:13 #7 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 12,240 Rep Power: 96 I do not know what you mean by calculation curve. You seem to be asking about the basics of CFX. You should read the documentation and do the tutorials.

 April 21, 2014, 09:41 #8 Senior Member   Join Date: Apr 2009 Posts: 530 Rep Power: 13 Monitor data is always shown in "Solution Units". These are shown and can be changed in CFX-Pre. They are SI units by default.

 April 21, 2014, 10:25 #9 Senior Member   ok Join Date: Oct 2013 Posts: 338 Rep Power: 5 Dear Maimouna， I have found a method of fluid-structure interaction to solve this problem.u can use CFX together with transient structure in workbench.Structure setting is conducted in the transient structure, and u should name a domain interface used to transfer data,then u can write a "inp" file.Flow setting is conducted in the CFX,choose ANSYS MultiField in the external solver coupling,and then inport the "inp"file.The solving way should be the coupling solution in the solution control. Dear Mal, many thanks for your reply. I have some questions please 1. What do you mean by using CFX together with transient structure in workbench? 2. What is ''inp'' file? 3. If I didn't have any experience in ANSYS, how can I do it? Kind regards Maimouna

April 27, 2014, 02:44
#10
New Member

Ma.L
Join Date: May 2013
Location: ShangHai,China
Posts: 17
Rep Power: 5
Quote:
 Originally Posted by Maimouna Dear Maimouna， I have found a method of fluid-structure interaction to solve this problem.u can use CFX together with transient structure in workbench.Structure setting is conducted in the transient structure, and u should name a domain interface used to transfer data,then u can write a "inp" file.Flow setting is conducted in the CFX,choose ANSYS MultiField in the external solver coupling,and then inport the "inp"file.The solving way should be the coupling solution in the solution control. Dear Mal, many thanks for your reply. I have some questions please 1. What do you mean by using CFX together with transient structure in workbench? 2. What is ''inp'' file? 3. If I didn't have any experience in ANSYS, how can I do it? Kind regards Maimouna
Dear Maimouna,
1.if you want to do some FSI case,you will use the CFX together with transient structure. CFX is for fluid calculation,and transient structure is for structure calculation.
2.The "inp"file is written in transient structure,when you do a FSI case,you should insert this file in CFX as you set the analysis type in CFX-pre.
3.Transient structure is not difficult for you,i think.You just set some boundary conditions and interface in it.For more help,you could look for some tutorials for transient structure.
Kind regards

 April 28, 2014, 06:05 #11 Senior Member   ok Join Date: Oct 2013 Posts: 338 Rep Power: 5 Dear Mal, many thanks for your answers. Kind regards

February 20, 2016, 02:21
#12
Member

N B Khan
Join Date: Jan 2014
Posts: 36
Rep Power: 4
Quote:
 Originally Posted by Mal Dear ghorrocks, Thanks for you reply, you are right. VIV = vortex induced vibration.i have used the method of coupled with ANSYS FEA to solve my case.The cylinder is holded by a mechanical spring..
Dear Mal,
Although it is very old post but I am really looking for help regarding this... I am also trying to calculate VIV on cylinder but could not find any tutorial or help,,,plz if you have any helping material plz plz plz forward it to me.

1. One querry regarding your study..how you hold cylinder by a mechanical spring?

Thank you very much in advance
Kind Regards
Niaz

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