CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT > Fluent UDF and Scheme Programming

6dof moving valve around point

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 10, 2016, 09:23
Default 6dof moving valve around point
  #1
New Member
 
Christoph
Join Date: Jul 2016
Location: Stuttgart, Germany
Posts: 8
Rep Power: 9
schlappeseppel124 is on a distinguished road
Hello All,

i got a problem concerning 6dof and UDF. I got a 3D case and would like to move a valve by the pressure, that is generated by a moving wall.

For the 6dof moving of the valve i used the following UDF:

#include "udf.h"
#include "math.h"


DEFINE_SDOF_PROPERTIES(Valve_6dof, prop, dt, time, dtime)
{
prop[SDOF_MASS] = 1.645e-8;
prop[SDOF_IXX] = 6.04e-15;
/*The values for mass and moment of inertia are very low because the valve is very small.*/

prop[SDOF_ZERO_TRANS_X] = TRUE;
prop[SDOF_ZERO_TRANS_Y] = TRUE;
prop[SDOF_ZERO_TRANS_Z] = TRUE;

prop[SDOF_ZERO_ROT_X] = FALSE;
prop[SDOF_ZERO_ROT_Y] = TRUE;
prop[SDOF_ZERO_ROT_Z] = TRUE;

/*The case is symmetric in x-direction.*/
prop[SDOF_SYMMETRY_X] = 1;
prop[SDOF_SYMMETRY_Y] = 0;
prop[SDOF_SYMMETRY_Z] = 0;

Message("6dof updated);

https://picload.org/image/rdpaapao/cfd.png

But the valve is not mooving at all.
1. As you can see in the picture i would like to rotate the valve around a certain point. Do I need to add that somehow?

2. Do i need to add the moment of inertia for SDOF_IYY and SDOF_IZZ because it is 3D or can i neglect it because it is only rotaiting around the x-axis.

3. The moment of inertia i calculated using the Steiner's theorem because it shall rotate not around the center but the point marked in the picture. Or do i need to link it to the cordinate system of the whole body?

Any help is appreciated. If you need any further information please let me know.

Thank you very much
schlappeseppel124 is offline   Reply With Quote

Old   November 10, 2016, 12:49
Default
  #2
New Member
 
Christoph
Join Date: Jul 2016
Location: Stuttgart, Germany
Posts: 8
Rep Power: 9
schlappeseppel124 is on a distinguished road
Is it possible that it has something to do with the inertia? That my inertia is too low like it is in this case?

http://www.cfd-online.com/Forums/flu...eleration.html
schlappeseppel124 is offline   Reply With Quote

Old   November 11, 2016, 11:57
Default
  #3
New Member
 
Christoph
Join Date: Jul 2016
Location: Stuttgart, Germany
Posts: 8
Rep Power: 9
schlappeseppel124 is on a distinguished road
And can anybody tell me what this message means:

6DOF angular solver has not converged

I could not find anything in the cfd-board or even the internet concerning this.

Thank you very much
schlappeseppel124 is offline   Reply With Quote

Old   February 21, 2017, 09:49
Default
  #4
Member
 
saurabh kumar gupta
Join Date: Jul 2016
Location: kanpur,india
Posts: 53
Rep Power: 9
rsaurabh is on a distinguished road
Hi,
Have you got the solution for your problem. i am also working on same type case where center of rotation is different from C.G of body. If possible we can work together.
i will be happy to share what i know.
Thanks.
Saurabh
rsaurabh is offline   Reply With Quote

Old   March 1, 2017, 10:29
Default
  #5
New Member
 
Christoph
Join Date: Jul 2016
Location: Stuttgart, Germany
Posts: 8
Rep Power: 9
schlappeseppel124 is on a distinguished road
Hey rsaurabh,

sorry for the late answer, no I did not solve my problem. I worked around the valve by simulating it with boundary conditions. But if u find out something new, it would be nice if you can share it here.
schlappeseppel124 is offline   Reply With Quote

Old   March 2, 2017, 00:31
Default
  #6
Member
 
saurabh kumar gupta
Join Date: Jul 2016
Location: kanpur,india
Posts: 53
Rep Power: 9
rsaurabh is on a distinguished road
Hi schlappeseppel124,
Try using ANSYS 17.2 or above. in those versions 6DOF setting is easy to manage. You have both options there, either do 6DOF setting in setting your case else use UDF. i have implied my setting while setting my case.

I hope this will help.
rsaurabh is offline   Reply With Quote

Old   July 10, 2017, 08:23
Default Old version solution
  #7
New Member
 
thibaut
Join Date: Mar 2017
Posts: 2
Rep Power: 0
alleau is on a distinguished road
Hi all,

The new setup of SDOF solver in fluent v17 is more understandable as rsaurabh said. However, you can define it on older versions as well.

The rotation center of a solid body is described as CG in Fluent.
Go to dynamic mesh, create/edit dynamic mesh zone, and rigid body for your moving solid. There are coordinates for the centre gravity location, if you enable Six DOF option.

Rotation will then be defined from this point.

Hope this help !
alleau is offline   Reply With Quote

Old   June 20, 2018, 08:55
Default
  #8
Member
 
Join Date: Sep 2016
Posts: 43
Rep Power: 9
diggee is on a distinguished road
Quote:
Originally Posted by rsaurabh View Post
Hi,
Have you got the solution for your problem. i am also working on same type case where center of rotation is different from C.G of body. If possible we can work together.
i will be happy to share what i know.
Thanks.
Saurabh
Hi Saurabh, did you manage to figure out how to rotate about a point different from the center of gravity? Please do let me know if you did, need help urgently!
diggee is offline   Reply With Quote

Reply

Tags
6dof, udf, valve

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
problem in toposet Ahmed Khattab OpenFOAM Pre-Processing 27 March 3, 2023 21:12
an odd(at least for me!) reconstructPar error on a field immortality OpenFOAM Running, Solving & CFD 3 June 3, 2013 22:36
CFX Post: Problems with moving point cloud for changing time steps spatialtime CFX 0 December 7, 2009 04:56
Comsol and moving point source jemteo COMSOL 0 September 12, 2009 00:24
Saving data at a point in moving domain sawa FLUENT 0 February 19, 2006 09:31


All times are GMT -4. The time now is 11:17.