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

one piston dynamic deforming and mesh moving simultaneously

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 20, 2014, 08:08
Default one piston dynamic deforming and mesh moving simultaneously
  #1
New Member
 
John Lu
Join Date: Jun 2014
Posts: 2
Rep Power: 0
john Lu is on a distinguished road
Hi, everyone
I am doing a simplified simulation about one piston deforming axially(Z axis) while moving directly along X axis simultaneously.

Firstly, for piston deforming:
I defined the piston bottom as a rigid body, the udf program is:
#include<stdio.h>
#include<math.h>
#include"udf.h"
DEFINE_CG_MOTION(piston, dt, vel, omega, time, dtime)
{
const PI=3.1415926;
vel[0]=-0.1;
vel[2]=-((0.771*sin(50*PI*time))/(1-0.0085*cos(50*PI*time))/(1-0.0085*cos(50*PI*time)));
}
while vel[2]defining the piston bottom moves along Z axis, vel[0] describing piston body move along X axis.
the piston cylndrical surface is defined as deforming, the geometry of which is defined as cylinder.

Secondly, for the piston movement, which is defined in "cell zone conditions" the X axis translational velocity is defined as -0.1m/s, the same as written in udf.

However, preview mesh motion shows negative cell volume.
What's the reason?

P.S.
If only dynamic mesh is used, no problem.
If only mesh motion is used, no problem.
But, if two of them are used, negative cell volume occurs.
john Lu is offline   Reply With Quote

Old   June 20, 2014, 08:13
Default
  #2
New Member
 
John Lu
Join Date: Jun 2014
Posts: 2
Rep Power: 0
john Lu is on a distinguished road
It seems that, once the piston cylndrical surface is defined as deforming-cylinder, which would not move though the piston movement is defined in "cell zone contions- mesh motion".

Last edited by john Lu; June 20, 2014 at 10:34.
john Lu is offline   Reply With Quote

Reply

Tags
deforming and moving

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
Dynamic Mesh Problem. Tom Clark FLUENT 10 June 21, 2021 05:27
moving mesh rolling piston JohannVV FLUENT 4 November 11, 2010 10:46
Dynamic Mesh moving interface help akash.iitb FLUENT 0 August 24, 2010 00:53
Moving and deforming mesh paolo FLUENT 0 June 19, 2003 09:12
udf for moving and deforming mesh xie haibo FLUENT 4 October 27, 2002 07:45


All times are GMT -4. The time now is 14:42.