|
[Sponsors] |
October 14, 2002, 05:17 |
SIMPLE algorithm and k-eps turbulence model
|
#1 |
Guest
Posts: n/a
|
I'm using SIMPLE-based control volume method and K-eps model to calculate the flow fields around airfoils,but when I use much more grids or highly stretched grids near the solid surface, the computation diverges,I don't know what caused this. Can anyone help me with that? thanks!
Zhang |
|
October 14, 2002, 06:35 |
a suggestion
|
#2 |
Guest
Posts: n/a
|
keep an eye on the n+ value. See whether the code diverges when n+ is < 11.63 in one of the cells? If that is the case, then derive the value of G, epsilon & wall shear stress using linear velocity profile !
|
|
October 15, 2002, 02:31 |
Re: a suggestion
|
#3 |
Guest
Posts: n/a
|
If y+ is getting small this can get tricky indeed, as you may not be respecting your model's assumptions. In Aero applications Low-Re k-E models are much more adapted as well as Shear Stress Transport k-Omega type models where you integrate to the walls.
|
|
October 15, 2002, 21:46 |
Re: a suggestion
|
#4 |
Guest
Posts: n/a
|
Dear Abhi
What's the meaning of G in your suggestion? YANG |
|
October 15, 2002, 21:55 |
Re: a suggestion
|
#5 |
Guest
Posts: n/a
|
Hi, Abhi
What's the lower limit of n+ for k-epsilon model near the solid wall? Thanks YANG |
|
October 16, 2002, 02:46 |
Re: a suggestion
|
#6 |
Guest
Posts: n/a
|
Yang,
You should read CFD textbook materials! Details about most classical models, their applications and restrictions can be found in the books by Versteeg and Malalasekera (1995) or Wilcox (1993) for a more exhaustive approach. These are only suggestions of reading; there exist a lot more. In these anyway you would find explanations on P and G terms (G is the production term due to body force in general) and a lot more... |
|
October 16, 2002, 03:50 |
Re: a suggestion
|
#7 |
Guest
Posts: n/a
|
Dear Holidays
Thanks a lot for you patient help. YANG |
|
October 16, 2002, 06:00 |
Re: a suggestion
|
#8 |
Guest
Posts: n/a
|
"G is the production term due to body force in general" - it originates when you go for Reynold's averaging. Look at the viscous dissipation.
|
|
October 16, 2002, 07:02 |
Re: a suggestion
|
#9 |
Guest
Posts: n/a
|
G is of the form Gbuoy (+Grot + Gresist) with Gbuoy which can be written as -Mu_effective/(Rho*Sigma_Rho)*g*GradRho, ie a term that accounts for buoyancy and body force effects...
|
|
October 16, 2002, 08:42 |
Re: a suggestion
|
#10 |
Guest
Posts: n/a
|
Was the question first coined by YANG ? Yang , give me some more inputs abt the way ur code is behaving. May be I can suggest something. READ Turbulent Flows by STEFAN POPE if u have not!!!!!!! A very very good book
|
|
October 21, 2002, 18:22 |
Re: SIMPLE algorithm and k-eps turbulence model
|
#11 |
Guest
Posts: n/a
|
i am using the TEACH-T code which uses the SIMPLE algorithm and K-E model and i want to modify it to solve unsteady problem what type of code ur using and what do u think of TEACH-T and could the modification be easily accomplished
|
|
May 28, 2012, 04:08 |
|
#12 |
New Member
milad
Join Date: May 2012
Posts: 1
Rep Power: 0 |
||
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
SIMPLE algorithm in 3D cylindrical coordinates | zouchu | Main CFD Forum | 1 | January 20, 2014 17:02 |
The correction on pressure equation of SIMPLE algorithm in MRFSimpleFOAM solver | renyun0511 | OpenFOAM Running, Solving & CFD | 0 | November 10, 2010 01:47 |
About Phase Coupled SIMPLE (PC-SIMPLE) algorithm | Yan Kai | Main CFD Forum | 0 | April 18, 2007 03:48 |
About Phase Coupled SIMPLE (PC-SIMPLE) algorithm | Yan Kai | FLUENT | 0 | April 13, 2007 23:17 |
SIMPLE algorithm | Jonathan Castro | Main CFD Forum | 3 | December 10, 1999 04:59 |