# RSM implementation

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

 September 23, 2004, 13:16 RSM implementation #1 Biga Guest   Posts: n/a Hy, mates. Does anybody here have any experience at implementing a Reynolds-stress (second-moment) closure into a CFD code? If positive, please, which were the numerical difficulties, and how were them solved? What are the tips for a robust implementation of such models into a numerical code? Thanx in advance! Best regards, Biga

 September 23, 2004, 20:21 Re: RSM implementation #2 Halim Choi Guest   Posts: n/a The most important parts of implementation of the second moment closure turbulence model are the introduction of the apparent viscosity, the source term linearization and the treatment of wall condition. These are well established now, especially by Lien and Leschziner. Read following papers by them. (1) 'Numerical aspects of applying second-moment closure to complex flows' in "Closure strategies for turbulent and transitional flows" edited by Launder and Sandham, pp.153-187, Cambridge University Press, 2002. (there are some typing errors in Table 1) (2) 'Second moment modelling of recirculating flow with a non-orthogonal collocated finite volume algorithm', in Turbulent Shear Flow 8, Springer, pp.205-222, 1993. (3) 'A general non-orthogonal finite volume algorithm for turbulent flow at all speed incorporating second-moment closure, Part 1; Numerical implementation' in Comp. Meths. Appl. Mech. Engrg. 114, pp.123-148. 1994. I hope this helps, Haalim Choi

 September 24, 2004, 14:37 Re: RSM implementation #3 Biga Guest   Posts: n/a Thank you for replying! Aren't the first two parts (apparent viscosity and source term linearization) only necessary in an implicit context? I'm currently working in an explicit (multistage Runge-Kutta) one. My question is also more on implementation "dirty work" , such as clippings, bounds etc that are necessary to (hopefully) control the time evolution of the Reynolds stresses. Just for information, I'm using the Batten, Craft and Launder model (Batten at. al, AIAA Journal, 99) low-Re RSM model in a compressible flow solver. Thanx, Biga

 September 25, 2004, 04:57 Re: RSM implementation #4 Halim Choi Guest   Posts: n/a Dear Biga; (1) The works by Lien and Leschziner are based on the semi-implicit (so called SIMPLE) algorithm. (2) I did not have any problems when I applied their method to natural, mixed and forced convection problems etc. You can used their method for compressible flows together with the SIMPLE algorithm, see reference-3. As you pointed out well, however, their method is meaningless for explicit method. Halim Choi.

 September 28, 2004, 16:00 Re: RSM implementation #5 Biga Guest   Posts: n/a I still couldnīt hand me those articles... itīs a bit hard to get them here in Brazil... Ok, the implicit treatments are meaningless for my explicit framework. There still is the wall BC treatment... but arenīt the reynolds stresses zero at the wall? Or does your "treatment of wall conditions" in your second reply mean other than BC, such as inhomogeinities pressure correlations and so on? Thanx very much for the help! =D Biga

 September 29, 2004, 19:28 Re: RSM implementation #6 Halim Choi Guest   Posts: n/a The wall boundary condition I am talking about is the treatment of Reynolds stresses near the wall when you use the wall function method in a nonorthogonal grid situation. If you uses the low-Reynolds number differential stress model, there is no problem. Halim Choi

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post Far CFX 15 March 20, 2014 22:34 thomek OpenFOAM Programming & Development 0 October 18, 2010 05:10 Eric Wang CFX 1 January 7, 2009 09:55 kallipygian OpenFOAM Running, Solving & CFD 0 October 13, 2008 07:29 venkatesh FLUENT 0 October 14, 2005 04:20

All times are GMT -4. The time now is 02:34.