CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > General Forums > Main CFD Forum

LES on unstructured grids, urgent!!!

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 11, 2006, 00:03
Default LES on unstructured grids, urgent!!!
  #1
Lv Xin
Guest
 
Posts: n/a
am a Ph.D student from Singapore and trying to implement the Dynamic Mixed Model for our compressible LES code. Our solver is vertex-based finite volume scheme on unstructured grids. A cell-vertex scheme is adopted here, i.e., all computed variables in dependent vector are stored at vertices of the triangular cell. For every vertex, a control volume is constructed by joining the centers of the cell to the centre of the edges using the median dual of the triangular grid. This configuration implies that the number of neighboring control volumes is a random value.

My problems lay in following areas:

1). What I am trying to use is a linear combination of the scale-similarity model and Germano-Lilly model. To compute the test-filtered variables, as well as the double basic filtered ones, we just use simple volume averaging. But the results seem not very good. I can't find any more information on the explicit filter implementation details on unstructured grids. Could you give me some details on it?

2). Our LES code seems not very stable on the boundary, especially on the far field inflow and outflow. In the current implementation, we don't introduce any special treatments after the integration of LES models. Are there any cautions we need to take care of for the boundary treatments in LES?

3). In the filtered energy equation, I have 5 terms to be modeled. Among them, some terms just can not be transferred to divergence form, which could be a problem in the traditional Finite Volume scheme. Could you give me some suggestions on how to deal with these terms for FV schemes?

Thank you very much for your time! Any suggestions are much appreciated!
  Reply With Quote

Old   September 12, 2006, 03:12
Default Re: LES on unstructured grids, urgent!!!
  #2
Lv Xin
Guest
 
Posts: n/a
I know there should someone who can help me!
  Reply With Quote

Old   September 16, 2006, 00:33
Default Re: problem addressed!
  #3
Lv Xin
Guest
 
Posts: n/a
The implementation is based on the discrete interpolation filters proposed by Marsden. Testing results show that the it is very stable and accurate.
  Reply With Quote

Reply


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
[Other] OpenFOAM - structured or unstructured Grids ? thomasduerr OpenFOAM Meshing & Mesh Conversion 22 November 25, 2018 00:18
small test cases for LES on unstructured grids Fab Main CFD Forum 1 October 23, 2007 14:54
combining structured and unstructured grids Shane FLUENT 2 January 23, 2007 21:57
upwind schemes,zonal grids and LES Prabhu Main CFD Forum 5 October 20, 1999 20:43
TVD/NVD in unstructured grids m.s. darwish Main CFD Forum 0 August 24, 1999 14:44


All times are GMT -4. The time now is 12:47.