CFD simulation of pedestrian-level wind conditions around buildings: Past achievements and prospects

Abstract

Context of Virtual Special IssueA Virtual Special Issue (VSI) is a Special Issue that consists of previously published papers in a given journal. The aim of a VSI is to identify and group a coherent set of such papers and to provide some post-publication perspectives. This VSI deals with papers on CFD simulation of pedestrian-level wind conditions around buildings, published in the Journal of Wind Engineering and Industrial Aerodynamics (JWEIA).Wind comfort and wind safety for pedestrians are important requirements for urban areas. In particular near high-rise buildings, high wind velocities are often introduced at pedestrian level that can be experienced as uncomfortable or even dangerous. Uncomfortable wind conditions have proven detrimental to the success of new buildings (Durgin and Chock 1982). Wise (1970) reports about shops that are left untenanted because of the windy environment that discouraged shoppers. Lawson and Penwarden (1975) report dangerous wind conditions to be responsible for the death of two old ladies after being blown over by sudden wind gusts near a high-rise building. Many urban authorities nowadays recognize the importance of pedestrian wind comfort and wind safety and require such studies before granting building permits for new buildings or new urban areas.Studies of wind comfort and wind safety involve combining statistical meteorological data with aerodynamic information and with wind comfort and wind safety criteria. The aerodynamic information is needed to transform the statistical meteorological data from the weather station (meteorological site) to the location of interest at the building site. At this location, the transformed statistical data are combined with the comfort and safety criteria to assess local wind comfort and safety. This procedure is schematically depicted in Figure 1. Wind statistics at the meteorological site can be expressed as potential wind speed (U pot ), i.e. corresponding to a terrain with aerodynamic roughness length z 0 = 0.03 m. The aerodynamic information usually consists of two parts: the terrain-related contribution and the design-related contribution. The terrain-related contribution represents the change in wind statistics from the meteorological site to a reference location near the building site, i.e. the transformation of U pot to U 0 . The design-related contribution represents the change in wind statistics due to the local urban design, i.e. the transformation of U 0 to the local wind speed U. Information on transformation procedures to determine terrain-related contributions can be found in e.g. Simiu and Scanlan (1986) and Verkaik (2006). The design-related contribution (i.e. the wind-flow conditions around the buildings at the building site) can be obtained by either wind-tunnel modelling or CFD. Wind comfort and safety criteria generally exist of a threshold value of the wind speed and an allowed exceedance probability of this threshold.

CFD simulation of train aerodynamics: Train-induced wind conditions at an underground railroad passenger platform

“…By far most of these studies focused on wind around buildings, as outlined in several review papers (Stathopoulos, 1997(Stathopoulos, , 2002(Stathopoulos, , 2006Baker, 2007;Mochida and Lun, 2008;Blocken et al, 2011Moonen et al, 2012;Blocken and Stathopoulos, 2013;Blocken, 2014). While early studies on pedestrian wind conditions around buildings were performed in atmospheric boundary layer wind tunnels, the past decade has seen a rapid increase in the use of CFD for this purpose (Blocken, 2014).…”

Large-eddy Simulation of flow and dispersion around an isolated building: Analysis of influencing factors

“…Computational Fluid Dynamics (CFD) is increasingly used to study flow and dispersion in built environments [1][2][3][4]. Most of these studies have been conducted using Reynolds-averaged Navier-Stokes (RANS) models [5][6][7][8][9].…”

Study on the influence of voids on high-rise building on the wind environment

“…Note that, beyond that there were a few studies to investigate the influences of modern building structures (such as buildings with platforms) on the relatively large area of low flow velocity at the leeward of the building. Blocken and Stathopoulos (2013) performed a comprehensive investigation in regard to CFD simulation on pedestrian-level wind condition utilizing a normalized mean wind speed (U/Ur) rather than speed ratio K because it could easily combine specific wind climates to determine wind speed statistics based on the magnitude and frequency of occurrence. This contributed to determine effectively the boundaries of low wind velocity region.…”