CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT

why RNG k-e is better & what does RNG really mean?

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

LinkBack Thread Tools Display Modes
Old   August 7, 2006, 22:01
Default why RNG k-e is better & what does RNG really mean?
Bonnie White
Posts: n/a

I don't fully understand why RNG k-e model is better than k-e modle? Does it solve more internediate variables, thus more computationally expensive?

Since no classic textbook introduces RNG k-e model, I asked some CFD professors, but they cannot explain clearly to me why we need "RNG" tech? One of them just said that RNG is an "old" method after LES has been developed.

Any advice? Thank you.

  Reply With Quote

Old   August 8, 2006, 09:14
Default Re: why RNG k-e is better & what does RNG really m
Posts: n/a
The RNG model uses a mathematical analysis called renormalization group theory to derive the constants in the k and e equations. In the standard k-e model the contants are entirely based on experimental data and are only applicable to the type of flow the constants are based on.

Since the RNG constants are derived from theory the model is applicable to a wider range of flows. As far as I can remember the RNG model only has one extra pressure strain term than the standard k-e. The RNG is therfore only slightly more computationally expensive and yields more accurate results.

The LES model gives far better results than RNG but the grid requirements for LES make it very time consuming. The model to use depends on what you are trying to analyze and the resources that you have.
  Reply With Quote


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
RNG k-epsilon model implementation romant OpenFOAM Running, Solving & CFD 1 November 23, 2011 10:19
HELP!! Prandtl numbers in RNG k-e turbulence model maoasis FLUENT 0 April 24, 2006 10:51
RNG k-e equation Mahshid NUMECA 0 October 24, 2005 09:51
rng les zxaar FLUENT 0 May 18, 2005 01:16
RNG with Schemit number zwdi FLUENT 0 August 2, 2004 11:54

All times are GMT -4. The time now is 19:09.