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Forum: OpenFOAM Running, Solving & CFD January 24, 2009, 11:52
Replies: 57
Views: 25,154
Posted By ngj
Hi Ivan As I have said abov

Hi Ivan

As I have said above, I do not have much experience with smooth walls, and the few trials I have carried out lead to error.

Thus I cannot help you much more, but I you have not read...
Forum: OpenFOAM Running, Solving & CFD January 23, 2009, 14:57
Replies: 57
Views: 25,154
Posted By ngj
Hi Ivan Please bear with me

Hi Ivan

Please bear with me, if I have underestimated you, but I believe you are confused about a couple of thing:

1. k_plus is the roughness height given in wall coordinates, and has...
Forum: OpenFOAM Running, Solving & CFD January 23, 2009, 11:13
Replies: 57
Views: 25,154
Posted By ngj
@(@1): That said, it should no

@(@1): That said, it should not be hard to take the 1.5 version of kOmegaSST and merge it with my kOmegaSSTRough from 1.4.1.

Good luck,

Niels
Forum: OpenFOAM Running, Solving & CFD January 23, 2009, 11:01
Replies: 57
Views: 25,154
Posted By ngj
Hi Ivan Well, that is a lot

Hi Ivan

Well, that is a lot of questions, thus I will try to answer them the best I can.

@1: I have not tried compiling it om 1.5, but one of my colleagues tried and as I recall was...
Forum: OpenFOAM Running, Solving & CFD September 23, 2008, 11:09
Replies: 57
Views: 25,154
Posted By ngj
Hi Louis The forcing of zer

Hi Louis

The forcing of zeroGradient is basically removed by deleting the files in the kOmegaSST, which makes that exact inquiry.

It is done in my own implementation above, if that could be...
Forum: OpenFOAM Running, Solving & CFD September 23, 2008, 07:18
Replies: 57
Views: 25,154
Posted By ngj
Hi Fabian If the patch is a

Hi Fabian

If the patch is a wall, it is correct that further computations are done.

E.g. "vectorField uGrad" means that the velocity gradient normal to the wall is computed in _every_ face...
Forum: OpenFOAM Running, Solving & CFD September 23, 2008, 05:00
Replies: 57
Views: 25,154
Posted By ngj
Even though a proof would be s

Even though a proof would be significantly better than intuitionhttp://www.cfd-online.com/OpenFOAM_Discus/clipart/happy.gif
Forum: OpenFOAM Running, Solving & CFD September 23, 2008, 04:59
Replies: 57
Views: 25,154
Posted By ngj
Hi Fabian If you consider e

Hi Fabian

If you consider e.g. omegaWilcox.H, then I loop over all boundaries. Those which are wall-type are further investigated.

In either I work with fields, thus I calculate the...
Forum: OpenFOAM Running, Solving & CFD June 26, 2008, 08:18
Replies: 57
Views: 25,154
Posted By ngj
BTW: forgot to mention that th

BTW: forgot to mention that this procedure is highly y+ dependent, i.e. U_f deltaY_wall / nu should be around 1 (at least).

/ Niels
Forum: OpenFOAM Running, Solving & CFD June 26, 2008, 07:38
Replies: 57
Views: 25,154
Posted By ngj
Hi Jean-Luc This is my work

Hi Jean-Luc

This is my working version, but haven't started the tested yet. I have implemented two versions of a omega-BC. The first is the one given in Wilcox (2006) and the second is a version...
Forum: OpenFOAM Running, Solving & CFD June 26, 2008, 04:05
Replies: 57
Views: 25,154
Posted By ngj
Hi Jean-Luc > Do you plan t

Hi Jean-Luc

> Do you plan to implement a roughness model?
I have already modified kOmegaSST -> kOmegaSSTRough, i.e. removed all functionality with regard to the wall functions and implemented...
Forum: OpenFOAM Running, Solving & CFD June 23, 2008, 09:46
Replies: 57
Views: 25,154
Posted By ngj
Thanks Jean-Luc I have made

Thanks Jean-Luc

I have made an implementation without the wall functions, i.e. in the way we discussed above, as I was not fond of the results with the standard implementation. I have begun...
Forum: OpenFOAM Running, Solving & CFD June 18, 2008, 05:33
Replies: 57
Views: 25,154
Posted By ngj
Hi Jean-Luc and Bart I know

Hi Jean-Luc and Bart

I know that you both have been working with kOmegaSST, and I have just begun reading the source for the turbulence module, and something is quite strange.

Basicly it...
Forum: OpenFOAM Running, Solving & CFD May 22, 2008, 06:02
Replies: 57
Views: 25,154
Posted By ngj
Hi Bart I am sorry to say,

Hi Bart

I am sorry to say, that I am not using any of the RANS-models in OpenFOAM. My knowledge is based on a study I did for my master thesis where I used an in-house numerical code and needed...
Forum: OpenFOAM Running, Solving & CFD March 5, 2008, 07:12
Replies: 57
Views: 25,154
Posted By ngj
Hi Jean-Luc I have had simi

Hi Jean-Luc

I have had similar problems with convergence, and I found that when using the correct tuning, something called PID-control actually yielded good results. It is a routine, which...
Forum: OpenFOAM Running, Solving & CFD March 4, 2008, 10:48
Replies: 57
Views: 25,154
Posted By ngj
Hi Jean-Luc First of all, I

Hi Jean-Luc

First of all, I would go for (ii). I seems to be the cheapest of the two.
I do not know how channelOodles is working, but the straight forward way would be to add an internal body...
Forum: OpenFOAM Running, Solving & CFD February 22, 2008, 05:16
Replies: 57
Views: 25,154
Posted By ngj
Hi Jean-Luc Well, that's ho

Hi Jean-Luc

Well, that's how it goes, but it is good to hear that the results are as expected. Did you implement the omega condition?

I have read the Hellsten article, and it is short....
Forum: OpenFOAM Running, Solving & CFD February 18, 2008, 08:18
Replies: 57
Views: 25,154
Posted By ngj
BTW, if you do not have Wilcox

BTW, if you do not have Wilcox (2006) the BC on omega is

omega = 40000 nu_wall / ks^2

where nu_wall is the kinematic viscosity of the fluid and ks is the DIMENSIONED roughness height. Make...
Forum: OpenFOAM Running, Solving & CFD February 15, 2008, 09:22
Replies: 57
Views: 25,154
Posted By ngj
Hi It should be said that

Hi

It should be said that I have never worked with smooth surfaces (main interest: sediment transporthttp://www.cfd-online.com/OpenFOAM_Discus/clipart/happy.gif), but I have found the following...
Forum: OpenFOAM Running, Solving & CFD February 15, 2008, 04:17
Replies: 57
Views: 25,154
Posted By ngj
Hi Jean-Luc The 30% is not

Hi Jean-Luc

The 30% is not surprising, if it comes from the k-epsilon model. It has been reported in [1] for channel flows that the k-epsilon model deviates up to 30% from the Moody diagrams at...
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