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

Unrealistic Temperature Gradients after refining mesh in some parts

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

Reply
 
LinkBack Thread Tools Display Modes
Old   December 16, 2014, 09:28
Default Unrealistic Temperature Gradients after refining mesh in some parts
  #1
New Member
 
Join Date: Apr 2014
Posts: 24
Rep Power: 3
skapetan is on a distinguished road
Hello,

I want to keep it short and describe my problem.

I generated a 2D Mesh for ribbed channel where I want to analyse conjugate Heat Transfer and validate experimental Nusselt data.

Some key facts from my analysis:
K-omega SST turbulence model, Contact-IF between Solid(Rib) and Fluid, AllY+-Treatment, WallY+ 0-13 ,Air enters the channel with an Temperatur of 293,15K, I set a constant heat flux of 200 W/m≤ for the channel bottom and rib bottom .


The channel consists of 12 ribs. The flow can be assumed as periodic. Therefore I evaluated just the Nu-Distribution between rib 9 and 10.


I've generated a grid which had a really good accurancy but I couldn't get satisfactory results for the validation.

Based on that I decided to refine the mesh from rib 9 to rib 10 and the walls were Heat is transfered. After refining I got a Wall Y+ values of <1 ( just for the near wall area from rib 9 to 10, rest of the channel remained between 0-13)

I expected to get better results (means more equal to the experimental data as before) in the refined area.

However I got unrealistic temperature gradients in the refined area of the solid and bad accurancy.

Can someone describe why the solution is that bad ?

I put some pictures in the attachment for better illustration.

I hope this helps.Thank you.
skapetan is offline   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
problems generating clean mesh Christian_tt OpenFOAM Native Meshers: snappyHexMesh and Others 0 May 16, 2014 10:58
Layers:problem with curvature giulio.topazio OpenFOAM Native Meshers: snappyHexMesh and Others 10 August 22, 2012 09:03
snappyHexMesh won't work - zeros everywhere! sc298 OpenFOAM Native Meshers: snappyHexMesh and Others 2 March 27, 2011 21:11
icem hexa mesh parts pb jaber Main CFD Forum 2 July 7, 2009 15:30
icem hexa mesh parts pb jaber FLUENT 0 June 12, 2009 18:06


All times are GMT -4. The time now is 12:45.