|
[Sponsors] |
![]() |
![]() |
#1 |
New Member
Join Date: Feb 2013
Posts: 7
Rep Power: 13 ![]() |
Hello guys,
Please, I need help Can anyone tell me what is the problem next message to appear: "6DOF object must have positive mass" ![]() After compilation, dynamic mesh options set-up I used next option in Fluent: "Mesh motion/Preview" and the program returned the message above. Here it is the udf: #include "udf.h" DEFINE_SDOF_PROPERTIES(airvehicle, prop, dt, time, dtime) { prop[SDOF_MASS] = 90.185; prop[SDOF_IXX] = 27.116; prop[SDOF_IYY] = 395.094; prop[SDOF_IZZ] = 395.094; } What is going on, why is this problem?????????????? Thank you very much for your help |
|
![]() |
![]() |
![]() |
![]() |
#2 |
New Member
Join Date: Nov 2012
Posts: 18
Rep Power: 14 ![]() |
Hey there,
In such cases which include sdof solver enabled, you shouldn't be able to preview the mesh motion directly. Because, it should require flow field properties to be solved in the first place. You may try to use a simple velocity profile in order to preview mesh motion and check your dynamic mesh settings. Hope it helps Koray |
|
![]() |
![]() |
![]() |
![]() |
#3 |
Senior Member
Paritosh Vasava
Join Date: Oct 2012
Location: Lappeenranta, Finland
Posts: 732
Rep Power: 23 ![]() |
It is possible that the box in your domain is not aligned with x,y,z coordinate system. I mean that the Ixx you have may not be applicable to face in x-direction. Similarly Iyy and Izz.
|
|
![]() |
![]() |
![]() |
![]() |
#4 |
New Member
Cristian SIC
Join Date: Dec 2014
Posts: 3
Rep Power: 12 ![]() |
Place the center of gravity of the floatng body coordinates in this path:
Dynamic mesh>Dinamic mesh zones>Center of Gravity Default is (0,0,0) please put here your corect values. ![]() |
|
![]() |
![]() |
![]() |
![]() |
#5 |
New Member
Join Date: Feb 2013
Posts: 7
Rep Power: 13 ![]() |
Thank you very much for your help! It helped a lot!
|
|
![]() |
![]() |
![]() |
![]() |
#6 |
Senior Member
Have a nice time!
Join Date: Feb 2016
Location: mech.eng.ahmedmansour@gmail.com
Posts: 291
Rep Power: 11 ![]() |
Hello, could you tell me the basics of using the 6 DOF in Fluent? Thanks
|
|
![]() |
![]() |
![]() |
![]() |
#7 |
New Member
Maharashtra
Join Date: Dec 2017
Posts: 13
Rep Power: 9 ![]() |
Hi
Could you please provide details about how to give simple velocity profile and preview the mesh motion when i am getting the error of "6DOF object must have positive mass". |
|
![]() |
![]() |
![]() |
![]() |
#8 |
Senior Member
Have a nice time!
Join Date: Feb 2016
Location: mech.eng.ahmedmansour@gmail.com
Posts: 291
Rep Power: 11 ![]() |
Hello dear Sachin , watch my tutorial and ask about anything you do not understand, I have shown how to use a udf for the variable velocity at inlet Thanks
https://youtu.be/vrhHs6QbyTU |
|
![]() |
![]() |
![]() |
![]() |
#9 |
New Member
Maharashtra
Join Date: Dec 2017
Posts: 13
Rep Power: 9 ![]() |
Thank you so much dear Ahmed.
|
|
![]() |
![]() |
![]() |
![]() |
#10 |
Senior Member
Have a nice time!
Join Date: Feb 2016
Location: mech.eng.ahmedmansour@gmail.com
Posts: 291
Rep Power: 11 ![]() |
||
![]() |
![]() |
![]() |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
How to calculate Mass moment of Inertia for 6DOF | vigii | FLUENT | 3 | February 22, 2017 06:29 |
[General] 2 datas on one plot | Akuji | ParaView | 46 | December 1, 2013 15:06 |
Water subcooled boiling | Attesz | CFX | 7 | January 5, 2013 04:32 |
Problem setting with chtmultiregionFoam | Antonin | OpenFOAM | 10 | April 24, 2012 10:50 |
particle, parcel and mass flow rate balance | flybird | FLUENT | 0 | May 24, 2007 11:44 |