CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Bugs

LES kOmegaSSTSAS / looking for RASProperties

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

Like Tree1Likes

Reply
 
LinkBack Thread Tools Display Modes
Old   February 4, 2010, 15:00
Default LES kOmegaSSTSAS / looking for RASProperties
  #1
Senior Member
 
Pierre-Olivier Dallaire
Join Date: Mar 2009
Location: Montreal, Quebec, Canada
Posts: 185
Rep Power: 8
podallaire is on a distinguished road
Hi,

I'm trying to run a sim using LES kOmegaSSTSAS but facing this strange error / anybody experienced that before ? Thanks

Create time

Create mesh for time = 0

Reading field p

Reading field U

Reading/calculating face flux field phi

Selecting incompressible transport model Newtonian
Selecting turbulence model type LESModel
Selecting LES turbulence model kOmegaSSTSAS
kOmegaSSTSASCoeffs
{
alphaK1 0.85034;
alphaK2 1;
alphaOmega1 0.5;
alphaOmega2 0.85616;
gamma1 0.5532;
gamma2 0.4403;
beta1 0.075;
beta2 0.0828;
betaStar 0.09;
a1 0.31;
c1 10;
Cs 0.262;
alphaPhi 0.666667;
zetaTilda2 1.755;
FSAS 1.25;
Cmu 0.09;
}

Courant Number mean: 0.003328494907 max: 0.04563852373

Starting time loop

Time = 0.1

Courant Number mean: 0.003328494907 max: 0.04563852373
deltaT = 0.1
smoothSolver: Solving for Ux, Initial residual = 1, Final residual = 0.0001447730244, No Iterations 1
smoothSolver: Solving for Uy, Initial residual = 1, Final residual = 0.004463225608, No Iterations 1
smoothSolver: Solving for Uz, Initial residual = 1, Final residual = 0.003346085113, No Iterations 1
GAMG: Solving for p, Initial residual = 1, Final residual = 0.04815958026, No Iterations 4
GAMG: Solving for p, Initial residual = 0.05136590869, Final residual = 0.001241589961, No Iterations 1
time step continuity errors : sum local = 7.87914026e-05, global = -9.572829191e-06, cumulative = -9.572829191e-06
GAMG: Solving for p, Initial residual = 0.007659904341, Final residual = 0.0001102955053, No Iterations 2
GAMG: Solving for p, Initial residual = 0.006646878643, Final residual = 3.869521047e-07, No Iterations 6
time step continuity errors : sum local = 2.623671733e-08, global = -3.116971313e-09, cumulative = -9.575946162e-06
smoothSolver: Solving for k, Initial residual = 0.9999999999, Final residual = 0.0009974693262, No Iterations 1


--> FOAM FATAL ERROR:

request for RASModel RASProperties from objectRegistry region0 failed
available objects of type RASModel are

0
(
)
podallaire is offline   Reply With Quote

Old   February 4, 2010, 16:15
Default SAS model
  #2
New Member
 
Kyungrock Kim
Join Date: Jun 2009
Posts: 20
Rep Power: 8
Kr_kim is on a distinguished road
Dear Dallaire

It's pretty weird. OF is asking RASModel type.
It might be worked in different machine. Anyway, it's a strange bug.

Best wishes

Kyungrock
Kr_kim is offline   Reply With Quote

Old   May 19, 2010, 12:36
Default
  #3
New Member
 
Jiang Lijun
Join Date: Mar 2009
Posts: 14
Rep Power: 8
L.J.Jiang is on a distinguished road
Hi, Dallaire

Did you solve this problem?
I encounter the same problem. ^_^

Lijun
L.J.Jiang is offline   Reply With Quote

Old   May 19, 2010, 13:03
Default
  #4
New Member
 
Jiang Lijun
Join Date: Mar 2009
Posts: 14
Rep Power: 8
L.J.Jiang is on a distinguished road
Hi, Dallaire

I think I found what's the problem.
Maybe you used the wrong wall treatment in omega as me, did you ues "omegaWallFunction"?
This BC isn't defined in LES models, I think.

Best wishes,
Lijun
L.J.Jiang is offline   Reply With Quote

Old   June 16, 2010, 15:52
Default
  #5
Member
 
Alex
Join Date: Apr 2010
Posts: 32
Rep Power: 7
aloeven is on a distinguished road
Yes, this is because you have used wall functions in 0/k and/or 0/omega
aloeven is offline   Reply With Quote

Old   August 17, 2011, 13:56
Default
  #6
New Member
 
Phil
Join Date: Mar 2011
Location: West Des Moines, Iowa, U.S.A.
Posts: 5
Rep Power: 6
peob is on a distinguished road
So which patchField type (wall treatment) are we supposed to use for omega?

It isn't obvious to me which patchField types to use.
I checked the tutorials (OF2.0.0 and OF1.7.1) and couldn't find anything involving kOmegaSSTSAS.

I'm using "kqRWallFunction" for the "k" patchField type, and the solver (OF2.0.0 pimpleFoam and pisoFoam) successfully runs through the k-equation, but "bombs" on the omega-equation (as noted above by Pierre-Olivier Dallaire)

Thanks.
Phil
peob is offline   Reply With Quote

Old   January 4, 2012, 15:44
Default
  #7
egp
Senior Member
 
egp's Avatar
 
Eric Paterson
Join Date: Mar 2009
Location: Blacksburg, VA
Posts: 197
Blog Entries: 1
Rep Power: 9
egp is on a distinguished road
Hi Phil,

Did you ever resolve this problem? I am looking at it now because one of the students in our group is using this model and came to me with a question on this. I would recommend two possible solutions,

1. use fixedValue for k and omega and make sure that the mesh is sublayer resolved so that you can use classical values near wall values.

2. hack the code and adapt the RAS b.c. for omegaWallFunction to your kOmegaSSTSAS model.

Eric
egp is offline   Reply With Quote

Old   February 29, 2012, 06:41
Default
  #8
New Member
 
Join Date: Mar 2009
Posts: 26
Rep Power: 8
ayoros is on a distinguished road
Hi everybody,

Did anyone tried, as Eric suggested, to adapt the omegaWallFunction to the kOmegaSSTSAS turbulence model ?

As for now, I use a viscous-resolved grid and a fixedValue for omega, but it is quite tricky in some cases.

Cheers,
Fabien
ayoros is offline   Reply With Quote

Old   March 23, 2012, 03:36
Default omegaWallFunction for kOmegaSSTSAS
  #9
Member
 
Masashi Ohbuchi
Join Date: Oct 2009
Posts: 72
Rep Power: 7
Ohbuchi is on a distinguished road
Hi,
I've tried to implement LES-version omegaWallFunction
for kOmegaSSTSAS model as follows.

1. copy RAS/derivedFvPatchFields/wallFunctions/omegaWallFunctions/omegaWallFunction to LES/derivedFvPatchFields/wallFunction

2. replace "RASModel" to "LESModel" in source code of omegaWallFunction

3. modify LESModel.H
#include nearWallDist.H

protected:
nearWallDist y_;
public:
// Member functions
//- Return the near wall distances
const nearWallDist& y() const
{
return y_;
}
4. modify kOmegaSSTSAS.C

void kOmegaSSTSAS::correct(const tmp<volTensorField>& gradU)
{
volScalarField G("LESModel::G", nuSgs_*0.5*S2);

Am I correct?
Attached Files
File Type: gz LES.tar.gz (9.0 KB, 42 views)
Ohbuchi is offline   Reply With Quote

Old   March 23, 2012, 11:40
Default
  #10
Member
 
Timo K.
Join Date: Feb 2010
Location: University of Stuttgart
Posts: 66
Rep Power: 7
timo_IHS is on a distinguished road
Hallo Masashi,

I think your coding of the omegaWallFunction should be correct.

But how do you set your BC for omega in kOmegaSSTSAS.C (in fact, you don't)?

In the RAS-version this is done by:
omega_.boundaryField().updateCoeffs();
after G
and you set it to the matrix after the omega equation:
omegaEqn().boundaryManipulate(omega_.boundaryField ());

I am not sure if you can transfer the procedure from RAS-SST to SAS, because the arrangement of the omega and k-equation is not the same!
Has anybody an opinion about that?

Best,
Timo
timo_IHS is offline   Reply With Quote

Old   March 23, 2012, 12:13
Default
  #11
Member
 
Timo K.
Join Date: Feb 2010
Location: University of Stuttgart
Posts: 66
Rep Power: 7
timo_IHS is on a distinguished road
BTW: I think the G is also wrong in version 2.0 (correct me if I am wrong)
if
volScalarField S2(2.0*magSqr(symm(gradU())));
G should be like this:
volScalarField G = nuSgs_*S2;
and not divided by 2
G should be the same as in RAS!

Any opinions?

Best

PS: @Masashi and all SAS-users: have you validated the SAS model against a test case?
timo_IHS is offline   Reply With Quote

Old   March 23, 2012, 21:21
Default kOmegaSSTSAS
  #12
Member
 
Masashi Ohbuchi
Join Date: Oct 2009
Posts: 72
Rep Power: 7
Ohbuchi is on a distinguished road
Hi, Timo

Thank you for your reply.
I agree with you about the notation of G.
But I've modified these code without much thought.
And I've checked my implementation with attached example.

Best regards,
Masashi Obuchi.

Quote:
Originally Posted by timo_IHS View Post
BTW: I think the G is also wrong in version 2.0 (correct me if I am wrong)
if
volScalarField S2(2.0*magSqr(symm(gradU())));
G should be like this:
volScalarField G = nuSgs_*S2;
and not divided by 2
G should be the same as in RAS!

Any opinions?

Best

PS: @Masashi and all SAS-users: have you validated the SAS model against a test case?
Attached Files
File Type: gz SASsample.tar.gz (3.2 KB, 40 views)
Ohbuchi is offline   Reply With Quote

Old   April 12, 2012, 03:48
Default Strange behavior of k and omega
  #13
Member
 
Timo K.
Join Date: Feb 2010
Location: University of Stuttgart
Posts: 66
Rep Power: 7
timo_IHS is on a distinguished road
It's me again,

I've tested the kOmegaSSTSAS model on the channel flow Re_tau=395, initialized with a LES simulation.
I encountered a strange behavior of the turbulent fields k and omega, after ~10 iterations those fields do NOT change any more, they stay completely unchanged. Also nuSgs does not change a lot any more (as it should corresponding to the turbulent structure).

Any opinion on that?

Best,
Timo
timo_IHS is offline   Reply With Quote

Old   June 20, 2012, 09:33
Default
  #14
Senior Member
 
louisgag's Avatar
 
Louis Gagnon
Join Date: Mar 2009
Location: Québec, QC, Canada
Posts: 208
Rep Power: 9
louisgag is on a distinguished road
Send a message via ICQ to louisgag
Hello everyone,

thanks for all your inputs concerning the kOmegaSSTSAS model. If I understand correctly, the model is still not usable for grids with near wall resolutions of y+>30, at least not without implementing a modified wall function.. Is that right?

-Louis
louisgag is offline   Reply With Quote

Old   June 21, 2012, 04:01
Default
  #15
Member
 
Tibor Nyers
Join Date: Jul 2010
Location: Hungary
Posts: 91
Rep Power: 8
Toorop is on a distinguished road
Hi Louis,
I have reported the problem and I got a very detailed explanation about the issue.
bug report - kOmegaSSTSAS requests RASModel RASProperties
Toorop is offline   Reply With Quote

Old   June 21, 2012, 07:57
Default
  #16
Senior Member
 
louisgag's Avatar
 
Louis Gagnon
Join Date: Mar 2009
Location: Québec, QC, Canada
Posts: 208
Rep Power: 9
louisgag is on a distinguished road
Send a message via ICQ to louisgag
Hi Tibor,

Thank you. I had read your bug report, and it indeed pretty much confirms that there is no High Reynolds models available for KomegaSSTSAS as of now, right?


-Louis

Last edited by louisgag; June 21, 2012 at 09:18.
louisgag is offline   Reply With Quote

Old   June 21, 2012, 08:19
Default
  #17
Member
 
Tibor Nyers
Join Date: Jul 2010
Location: Hungary
Posts: 91
Rep Power: 8
Toorop is on a distinguished road
Yeah, that's my final conclusion as well.
Toorop is offline   Reply With Quote

Old   July 20, 2012, 06:01
Default
  #18
New Member
 
Jane L
Join Date: May 2012
Posts: 21
Rep Power: 5
Jane L is on a distinguished road
In that bug report mentioned above, it is stated, that this issue should be fixed in version 2.1.1. I'm still not able to use omegaWallFunction in LES. Did anyone of you check?

I'm still wondering why OpenFOAM doesn't complain about kqRWallFunction which isn't part of LES either.

Any ideas?

best regards!
Jane L is offline   Reply With Quote

Old   July 20, 2012, 10:31
Default
  #19
Senior Member
 
louisgag's Avatar
 
Louis Gagnon
Join Date: Mar 2009
Location: Québec, QC, Canada
Posts: 208
Rep Power: 9
louisgag is on a distinguished road
Send a message via ICQ to louisgag
I don't think near wall treatment for the kOmegaSSTSAS is yet available.
louisgag is offline   Reply With Quote

Old   March 21, 2014, 17:41
Default
  #20
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,097
Rep Power: 16
RodriguezFatz will become famous soon enough
Hi all, I hope some of you are still active in this forum.
The issue is still the same as I understand it. The SAS model indeed accepts the omega wall function nowadays (I think since 2.2) but doesn't evaluate it at all. This is really confusing.
But: The two models differ just by this one Fsas term, right? So wouldn't it be sufficient, if we just make a copy of the RAS model directory and add this one term? All wall function usage would be correct then, I guess.
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Reply

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
LES and SST together Roland R CFX 6 December 21, 2009 13:26
LES and combustion model Margherita Cadorin CFX 0 October 29, 2008 06:24
Differences between a laminar code and a les one ben Main CFD Forum 9 February 17, 2005 00:40
LES on two phase flow Li Yang Main CFD Forum 0 May 12, 2004 08:10
Some Questions about LES. Bin Li Main CFD Forum 2 February 20, 2004 10:58


All times are GMT -4. The time now is 23:17.