This project is conducted in order to investigate the possibilities of analysing wind conditions at pedestrian level by use of Computational Fluid Dynamics (CFD). The purpose is to establish an operational procedure for evaluating wind conditions by coupling CFD, wind statistics, and evaluation criteria.

The project consists of three parts:

Part I deals with the problem of formulating evaluation criteria based on mean wind speed and turbulence. Based on the literature criteria are established for comfort and danger, along with limits of how often the criteria should be allowed to be exceeded.

Part II presents the mathematical model used to evaluate the flow field. This includes treatment of the wind statistics, modelling boundary conditions, selection of turbulence model, and comparison of the CFD model with field measurement in order to evaluate the proposed model.

It is showed that the SST k-ω model by Menter (1994) with parameters suggested by Yang et al. (2009) is best for modelling the turbulence. A method for transformation of wind statistics from meteorological sites to the location of interest is applied based on the work of Verkaik et al. (2005) and Wieringa (1986).

The overall procedure of evaluating wind conditions is presented, and in Part III two case studies are conducted. One from Høje Brygge, Nørresundby, where also the field measurements are conducted. Here the residents suffer under severe wind conditions. The other case study, from Viborgvej/Bredskiftevej in Århus, is for a proposed group of high-rise buildings.

In both cases the comfort and danger are evaluated and a number of solutions are suggested in order to reduce the wind speed at ground level. The directional discretisation is investigated and considerations on how to choose an adequate discretisation is presented.