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

Another LES filtering question

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 14, 2003, 08:24
Default Another LES filtering question
  #1
Tim
Guest
 
Posts: n/a
Hi,

If I would like to explicitly filter a variable in LES then how would I do this?

If I just apply a filter to a F-V cell centred variable I am explicitly filtering an already impicitly filtered variable. Do I have to somehow undo the implicit filter before applying an explicit filter? If so how?

Does anyone know how much the accuracy varies for a case using the same subgrid model but with differing filtering techniques?

Thanks

Tim.

  Reply With Quote

Old   November 21, 2003, 08:54
Default Re: Another LES filtering question
  #2
Lionel Larcheveque
Guest
 
Posts: n/a
Hi

I don't know way to remove implicit filtering. In fact, using explicit filter correspond to apply a filter which comes from the convolution of the explicit filter with the implicit filter. So the explicit filter has to have a lower cutoff length than the implicit filter so as to reduce the influence of the implicit one in ``total'' filtering.

For accuracy with and without explicit filtering, you may have a look at this recent article : J. Gullbrand and F. K. Chow, 2003. "The effect of numerical errors and turbulence models in large-eddy simulations of channel flow, with and without explicit filtering", J. Fluid Mech. Vol. 495, pp 323-341

Best regards
  Reply With Quote

Old   December 10, 2003, 14:30
Default Re: Another LES filtering question
  #3
Mariafrancesca Valentino
Guest
 
Posts: n/a
Hi! I'm interested in the paper you saggested; I've checked but in the 2003 there is no volume 495 for the Journal of fluid mechanincs. Are you sure that the data you gave are right? Could you check for them? I'll be very grateful to you.

Best regards Mariafracesca Valentino

you wrote:

For accuracy with and without explicit filtering, you may have a look at this recent article : J. Gullbrand and F. K. Chow, 2003. "The effect of numerical errors and turbulence models in large-eddy simulations of channel flow, with and without explicit filtering", J. Fluid Mech. Vol. 495, pp 323-3
  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
LES basic and simple questions. dshawul Main CFD Forum 0 October 4, 2010 11:56
Naive question about turbulence and LES Renato Main CFD Forum 1 October 5, 2005 00:01
question about LES gino briganti FLUENT 3 June 27, 2005 07:05
A question about LES yfjma OpenFOAM Installation 0 May 31, 2005 01:10
A Question on the Dynamic procedure in LES dragon Main CFD Forum 1 April 28, 2005 16:11


All times are GMT -4. The time now is 09:01.