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

6dof produces rotation in quiescent fluid

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 9, 2018, 02:54
Default 6dof produces rotation in quiescent fluid
  #1
New Member
 
Saiwei Li
Join Date: Mar 2018
Posts: 1
Rep Power: 0
Sylviii is on a distinguished road
To familiarize with 6dof, I am trying a very simple case involving a rod hinged at one end. The case is 2D transient, pressure-based, zero gravity. The model is simple, just four stationary walls that forms a chamber, enclosing a bulk of air. The rod is in the middle of the chamber. There is no flow.
The rotation axis and center of gravity are both (0,0). The moment of inertia of the rod is 1.
When dynamic mesh is turned off, everything is fine, there is no flow, and there is zero pressure everywhere.
However, once I switch dynamic mesh on, and activate one-dof rotation for the rod, remeshing for the surrounding mesh, something strange happens. Somehow, the solver decides that the rod should rotate, and produces very high pressure (~1e5-1e6) above the rod, and low pressure below the rod. Checking the dynamic mesh zones setting, I can see that there is a rigid body angular velocity of ~5, i.e., the rod is rotating.
My questing is, why is the rod rotating even in quiescent fluid? What might the problem be? I re-emphasize that there is no fluid flow, no gravity, no buoyancy, no spring load, zero gravitational acceleration, nothing that can drive the rotation. Just a rod in a chamber filled with still air.
Sylviii is offline   Reply With Quote

Reply

Tags
6dof, fluent, one-dof, sdof

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
[Tutorials] Flow induced rotation with AMI and 6DOF Tobi OpenFOAM Community Contributions 12 December 30, 2023 03:27
6DOF Solver - Center of Mass and Center of Rotation Verse OpenFOAM Running, Solving & CFD 0 October 13, 2016 14:51
[snappyHexMesh] How to define to right point for locationInMesh Mirage12 OpenFOAM Meshing & Mesh Conversion 7 March 13, 2016 14:07
My Revised "Time Vs Energy" Article For Review Abhi Main CFD Forum 2 July 9, 2002 09:08
Terrible Mistake In Fluid Dynamics History Abhi Main CFD Forum 12 July 8, 2002 09:11


All times are GMT -4. The time now is 11:54.