Hi,

I was wondering if anyone knows if there are any books, articles, papers, handbooks,experiments, etc. about flow through/in big cities?

Regards, Maria Gaardsted

what do you mean by flow through/in big cities!!! please

External airflow, of course!!! Instead of having, for example, microscopic dimensions as in a room or a box, I am searching for any kind of materials involving macroscopic flow in large cities, i.e. airflow distribution in streets due to the placements of buildings. As far as I am concerned very little research has been made so far in this area, why it is difficult to find materials about it. I would like to see earlier examples of cfd modelling concerning this subject, that´s all.

Please check out www.fluidyn.com. We have been modelling atmospheric dispersion of pollution for several years now. This involves the CFD computation of the wind field on domains, going from a street level(several hundred meters) to a region level (several hundred kilometers). Our references include several French, as well as UK, cities.

Hope this helps,

Amita

I think that most cfd software vendors can't show you example of such flow.

I know that at least two companies sells dedicated software or add on for atmospheric flows : CFDRC and ARIA technologie.

The main difficulties in this kind of flow is geometry /meshing of topological datas and turbulence behavior of the flow due to the large scale.

You can also have a look at the web site of the "Ecole Centrale de Nantes" (a french engineer scool). They have done many macro scale simulation of external flow.

Best regards

Alain

On the contrary I think this is becoming more and more topical and most major CFD players do this type of job, looking at flows around a whole district to determine level of pollution or the effect of a new building on wind flows etc. major architecture companies and builder require this...

Sorry I made a typing mistake and I just said the contrary of that I had in thought :

Instead of "...most vendors can't..." you should read "...most vendors can"

Alain

Have a look at www.cfdrc.com/datab/applications/uds/uds.html, they have a specialist cfd development to model dispersion on a street block level sounds like this might be what you are looking for.

This web page has been pulled down. Does anyone have another reference for this type of modeling?

We are presently developing a specialized CFD-based module for a well known and widely used dispersion modeling tool called HPAC. This "Urban Dispersion Simulator" (UDS) is based upon many components of our product line, CFD-ACE+. As noted in some of the discussion, the most difficult part of modeling cityscapes is the actual model generation. We are advancing many technologies developed in other industries (such as semiconductor device modeling and MEMS simulations), and adapting them to the Urban dispersion modeling area. This allows us to use common GIS data, CAD data and others, such as SEDRIS Transmittal Format and STL, and quickly generate accurate models of the city. Our physical models include many standard turbulence models, Eulerian/Lagrangian particle transport, Eulerian transport of gas-phase dispersants, solar radiation modeling using surface-to-surface radiation models and others. Presently, we are focusing on RANS modeling, but are capable (and have demonstrated) using LES for the dispersant modeling. The UDS runs locally and/or remotely upon distributed clusters of workstations running Linux, MS 2000/NT and many other platforms.

We are presently updating our web site. If you visit:

http://www.cfdrc.com

and then click on "Environmental, CBW Protection", you can get an idea of what we are developing. If you all are interested, I'll be glad to notify you when we are finished updating our site.

So... To make a long story short: Yes! CFD in big cities is not only possible, but we've been doing it for a while, and it works great!

If you want more info, please email me directly...

Good luck.