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Search took 0.00 seconds. Search: Posts Made By: romant
Forum: OpenFOAM March 13, 2015, 09:20
Replies: 63
Views: 24,119
Posted By romant
It is true that in the log region, linearity...

It is true that in the log region, linearity cannot be used, however, you don't have any other values. Please take a look at Pope, Turbulent Flow, 2000, pp. 443, where the method on how to obtain...
Forum: OpenFOAM March 13, 2015, 03:49
Replies: 63
Views: 24,119
Posted By romant
When you take a look at the link that is posted...

When you take a look at the link that is posted with this explanation, you can see that the linear interpolation (which is the only one available in a CFD code) is used to insert the logarithmic form...
Forum: OpenFOAM August 15, 2013, 05:20
Replies: 63
Views: 24,119
Posted By romant
I think I made a mistake in the answer of this...

I think I made a mistake in the answer of this question, however, I can't change the answer anymore. So I looked into this again. nut is defined on the wall and not in the first grid point, is...
Forum: OpenFOAM March 6, 2013, 07:49
Replies: 63
Views: 24,119
Posted By romant
Sorry, I don't think I can help you there, I...

Sorry, I don't think I can help you there, I haven't really looked into that wall function. Maybe somebody else knows what to do there.
Forum: OpenFOAM March 6, 2013, 06:19
Replies: 63
Views: 24,119
Posted By romant
There is special wall functions for rough walls,...

There is special wall functions for rough walls, therefore this is not a problem.
Forum: OpenFOAM March 6, 2013, 05:53
Replies: 63
Views: 24,119
Posted By romant
Hej, I didn't write the article, but only...

Hej,

I didn't write the article, but only modified a mistake in the article. However, I think your conclusion is right. Many time, you assume smooth walls in CFD, and this way the grain size...
Forum: OpenFOAM July 23, 2012, 10:13
Replies: 63
Views: 24,119
Posted By romant
The reason comes from the way OpenFOAM is...

The reason comes from the way OpenFOAM is programmed. Every boundary condition needs to have a value specified, due to the fact that all boundaries inherit a certain basic functionality from a basic...
Forum: OpenFOAM December 21, 2011, 02:38
Replies: 63
Views: 24,119
Posted By romant
you could create your own kEpsilon model, where...

you could create your own kEpsilon model, where you basically copy this whole thing and edit the part where sigmaK is missing, just follow the code and you should be fine.
Forum: OpenFOAM December 16, 2011, 03:27
Replies: 63
Views: 24,119
Posted By romant
In the case y+<11 it is usually adopted to the...

In the case y+<11 it is usually adopted to the refine the mesh so that y+<1 since then the mesh is fine enough to resolve most of the phenomena in the boundary layer (Pope, Turbulent Flow, 2000)....
Forum: OpenFOAM December 16, 2011, 03:24
Replies: 63
Views: 24,119
Posted By romant
Tutorials are there to give an idea of how...

Tutorials are there to give an idea of how everything should be set up, they are not real life cases and results are not validated against experimental data.

There are different considerations...
Forum: OpenFOAM December 1, 2011, 04:32
Replies: 63
Views: 24,119
Posted By romant
You can use the yPlusRAS utility to check your y+...

You can use the yPlusRAS utility to check your y+ in your simulation. In order to use wall functions, it should be between 30 and 150. if you have less at certain points, make the cells bigger and if...
Forum: OpenFOAM November 28, 2011, 05:50
Replies: 63
Views: 24,119
Posted By romant
I changed it on the wiki page, it should be OK now

I changed it on the wiki page, it should be OK now
Forum: OpenFOAM November 28, 2011, 04:36
Replies: 63
Views: 24,119
Posted By romant
log law in compact version

Hej,

I just found how this is derived and calculated it myself, http://www.cfd-online.com/Wiki/Two_equation_turbulence_models#Standard_wall_functions

if you see how the rho is eliminated,...
Forum: OpenFOAM November 28, 2011, 03:25
Replies: 63
Views: 24,119
Posted By romant
In 2.0 more nutWallFunction boundary conditions...

In 2.0 more nutWallFunction boundary conditions were introduced, one of them nutUWallFunction, where basically the way of how yPlus is calculated is changed.
Forum: OpenFOAM November 28, 2011, 03:20
Replies: 63
Views: 24,119
Posted By romant
the boundary condition nutkWallFunction sets the...

the boundary condition nutkWallFunction sets the turbulent viscosity in the first node point based on the logarithmic law of the wall http://en.wikipedia.org/wiki/Law_of_the_wall . the difference...
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