[AvaShahrokhi]

Hi everybody

I am doing wind farm assessment of the atmospheric boundary layer in an urban area with building and trees and I am going to use LES.


I am trying to find a paper that gives me an idea about the grid scales that I need to use in the first grid adjacent to the ground and the suitable y+ for my case and I have not find anything in the literature up to now.

The thing is that the area of the site that I am doing the simulation is about one kilometre so I need to use as course mesh as possible.


Could anybody give me some idea about this?

Thank you,
Ava.

[FMDenaro]

have you tried searchig for in Google?
For example
https://www.google.it/#q=les+atmospheric+boundary+layer

there are many papers about LES of atmospheric/oceanic flows ..

[AvaShahrokhi]

Hi Filippo

thank you for your response. I did searched but did not find satisfying explanations. The vertical grid resolutions in the papers range from few meters to 1-2 kilometres.

Ava.

[FMDenaro]

Originally Posted by AvaShahrokhi

Hi Filippo

thank you for your response. I did searched but did not find satisfying explanations. The vertical grid resolutions in the papers range from few meters to 1-2 kilometres.

Ava.

yes, the mesh size is from orde of the meter to some tenth, it depends on the problem and (of course) on the computational power. Sometime, proper BC must be specified for unresolved BL, as well as some more sophisticated LES model are useful. I suggest a reading to these papers
http://www.me.jhu.edu/meneveau/pubs-fieldLES.html

[AvaShahrokhi]

Long list! thank you so much though. I had a quick look at some in the past.
So it seems that it is not very straightforward and depends on many other things in the numerical modelling.

Ava.

[FMDenaro]

Originally Posted by AvaShahrokhi

Long list! thank you so much though. I had a quick look at some in the past.
So it seems that it is not very straightforward and depends on many other things in the numerical modelling.

Ava.

yes, many issues can be relevant in such problems, wind shear, natural convection, Coriolis...you need to include the relevant effects of your problem and consider if you need to resolve the BL or to use some model...
you can find useful information also in papers describing LES of marine flows