CFD Online URL
[Sponsors]
Home > Forums > FLUENT

significant gap between the wall and moving piston

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

Reply
 
LinkBack Thread Tools Display Modes
Old   August 28, 2006, 06:23
Default significant gap between the wall and moving piston
  #1
Sha
Guest
 
Posts: n/a
Hi, In my problam, There is a cylinder and a psiton that creates gaps in both sides, More precisely, There are three walls - that look like this : |_| and a rigid wall(piston) that moves in sin way up and down ,The piston is narrow in a way that two gaps are created in the left and right sides.

I am only intersting in the flow inside the cylinder, The area over the piston is not intersting. I will totaly appriciate detailed explantion for the soultion of this problam. I realy dont have a clue, I read a little about dynamic mesh and i preffer not to deal with UDF(its sounds complicated)

Thanks a lot in advance, Sha.
  Reply With Quote

Old   August 28, 2006, 14:21
Default Re: significant gap between the wall and moving pi
  #2
Ahmed
Guest
 
Posts: n/a
Look the tutorial for a sliding mesh
  Reply With Quote

Old   August 28, 2006, 16:24
Default Re: significant gap between the wall and moving pi
  #3
benjo
Guest
 
Posts: n/a
hi, i have the same problam, anyone can advice a simple way to solve this problam ?
  Reply With Quote

Old   September 20, 2006, 07:08
Default how can modeling a moving wall?
  #4
Nikolaos
Guest
 
Posts: n/a
My model consists of a box where in the top of it and in the bottom bordering with a moving wall. between the box and the moving wall exist air. the moving wall moves in the x-axis with 10 m/sec. how can give the boundary conditions to the moving wall?

please help me!!!
  Reply With Quote

Old   September 20, 2006, 12:15
Default Re: how can modeling a moving wall?
  #5
Albert F.
Guest
 
Posts: n/a
As I know you need to specify a velocity in the wall you want. You can do this by changing a couple of things in the momentum panel of the wall:

Wall motion: Moving wall

Motion: Relative to adjacent wall (if adjacent cell is air for exemple)

Shear Stress: here there are two options no slip or specify shear. I usually specify shear stress with 0 constant stress on both directions (X an Y) to achieve a velocity profile where the velocity is 0 near the wall.

If you have defined the shape as a solid you have to impose a moving reference frame on bc panel.

I don't know If I have explained it clearly, any doubt ask me for more info. Hope it helps.
  Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
UDF for slip and moving wall lichun Dong FLUENT 3 March 26, 2014 06:37
stationary wall vs. moving wall user0314 FLUENT 0 August 26, 2011 10:42
gap between the wall and moving piston Nan CFX 10 April 26, 2011 23:04
Convergence moving mesh lr103476 OpenFOAM Running, Solving & CFD 30 November 19, 2007 15:09
Deal with wall boundary with moving mesh by FVM? aiya Main CFD Forum 6 May 10, 2007 12:33


All times are GMT -4. The time now is 05:27.