Abstract
Wind flow in urban areas is strongly affected by the urban geometry. In the last decades most of the geometries used to reproduce urban areas, both in wind-tunnel (WT) tests and Computational Fluid Dynamics (CFD) simulations, were simplified compared to reality in order to limit experimental effort and computational costs. However, it is unclear to which extent these geometrical simplifications can affect the reliability of the numerical and experimental results. The goal of this paper is to quantify the deviations caused by geometrical simplifications. The case under study is the district of Livorno city (Italy), called “Quartiere La Venezia”. The 3D steady Reynolds-averaged Navier-Stokes (RANS) simulations are solved, first for a single block of the district, then for the whole district. The CFD simulations are validated with WT tests at scale 1:300. Comparisons are made of mean wind velocity profiles between WT tests and CFD simulations, and the agreement is quantified using four validation metrics (FB, NMSE, R and FAC1.3). The results show that the most detailed geometry provides improved performance, especially for wind direction α = 240° (22% difference in terms of FAC1.3).
Highlights
The complex morphology of cities renders the analytical description of wind flow in urban areas very difficult
Many researchers have investigated different aspects of urban flows, but at present the urban boundary layer (UBL) is not yet completely understood WT tests and Computational Fluid Dynamics (CFD) simulations are frequently used in urban physics and wind engineering to gain increased understanding
The 3D steady-state Reynolds-averaged Navier-Stokes (RANS) approach with the realizable k-ε turbulence model was applied to simulate mean wind-velocity patterns in a single block of Quartiere La Venezia and in the whole urban district reproduced at reduced scale (1:300)
Summary
The complex morphology of cities renders the analytical description of wind flow in urban areas very difficult. Wind flow in urban environments is governed by a variety of complex factors, such as the heterogeneous geometry of buildings, flow impingement, separation and recirculation and local thermal effects. The region above the buildings, usually defined as the urban boundary layer (UBL), is influenced by continuously changing surface roughness, so that the wind flow never reaches a homogeneous equilibrium condition. The situation is even more complex within the urban canopy layer (UCL), where streets give rise to complex canyoning effects that are strongly dependent on the canyon orientation with respect to the incoming wind. Carpentieri and Robins (2015) analyzed the impact of morphological parameters on wind flow in the UCL Their results show how the building height variability, the angles between street canyon orientations and incoming wind and other local geometrical features can strongly influence the characteristics of the urban flow
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of Wind Engineering and Industrial Aerodynamics
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
