CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > Siemens > STAR-CCM+

Morphing Mesh Cylinder

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 6, 2019, 14:08
Default Morphing Mesh Cylinder
  #1
New Member
 
Join Date: Aug 2019
Posts: 1
Rep Power: 0
okabis is on a distinguished road
Hey everyone,


i'm trying to simulate a simple piston, which pushes air into another region.
for an easy start i tried to simulate only the piston in form of a simple cylinder (h=0.715m, r=0.1533m) first.

for the movement i set up a morphing mesh:
- the top with a total linear displacement in y direction, defined by a field function (graph attached). it's supposed to move down and up within 1s

- the walls as floating
- the base is fixed
i didn't change anything in the options for the morphing tool or the morphing solver and used the k-omega turbulence model.

for the mesh, i chose an automated polyhedral mesh with base size 0.02m (picture attached).
as simple as the simulation seems to be, my solution doesn't converge at all (picture attached for 0.05s time step) with residuals up to 1000. i tried time steps from 0.1s to 0.001s, but the finer the step, the worse it gets. changing the mesh didn't do anything either. finer or coarses meshes made no changes. i also tried a trimmed mesh, since i thought it might be better for the morphing, but still no better results...


since the problem itself seems to be quite easy and all changes seem to have no impact, i start to believe, that there must be something wrong in the setup of the morphing...
i hope you guys can help me in any form!



thanks in advance,
okabis




EDIT: well, since i should have put a little less of my concentration on the morphin i should have checked the physics...the problem seems to have been the constant density (of course...). looks like i am not able to delete this thread
Attached Images
File Type: jpg mesh_mitte.jpg (36.7 KB, 6 views)
File Type: jpg mesh_scene.jpg (24.5 KB, 6 views)
File Type: png translation_y.png (21.3 KB, 7 views)
File Type: jpg mesh_compressed.jpg (23.1 KB, 6 views)
File Type: jpg residuals.jpg (103.8 KB, 7 views)
okabis is offline   Reply With Quote

Old   November 6, 2019, 16:28
Default
  #2
Senior Member
 
Matt
Join Date: Aug 2014
Posts: 776
Rep Power: 12
fluid23 is on a distinguished road
how many inner iterations did you use?

nevermind, I see your edit
fluid23 is offline   Reply With Quote

Reply

Tags
morphing mesh, piston

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
decomposePar problem: Cell 0contains face labels out of range vaina74 OpenFOAM Pre-Processing 32 February 7, 2018 09:26
[snappyHexMesh] SnappyHexMesh for internal Flow vishwa OpenFOAM Meshing & Mesh Conversion 24 June 27, 2016 09:54
[mesh manipulation] Importing Multiple Meshes thomasnwalshiii OpenFOAM Meshing & Mesh Conversion 18 December 19, 2015 19:57
Forces Acting on a Rotating Cylinder (Moving Mesh) dreamchaser CFX 5 April 25, 2015 07:01
rotating cylinder using sliding mesh Tim Daly FLUENT 1 November 10, 2008 00:02


All times are GMT -4. The time now is 16:32.