Abstract
An increasing number of engineering applications require accurate predictions of the flow around buildings to guarantee performance and safety. This paper investigates the effects of variations in the turbulent inflow, as predicted in different numerical simulations, on the flow pattern prediction around buildings, compared to wind tunnel tests. Turbulence characteristics were assessed at several locations around a model square high-rise building, namely, above the roof region, at the pedestrian level, and in the wake. Both Reynolds-averaged Navier–Stokes (RANS, where turbulence is fully modelled) equations and large-eddy simulation (LES, where turbulence is partially resolved) were used to model an experimental setup providing validation for the roof region. The performances of both techniques were compared in ability to predict the flow features. It was found that RANS provides reliable results in regions of the flow heavily influenced by the building model, and it is unreliable where the flow is influenced by ambient conditions. In contrast, LES is generally reliable, provided that a suitable turbulent inflow is included in the simulation. RANS also benefits when a turbulent inflow is provided in simulations. In general, LES should be the methodology of choice if engineering applications are involved with the highly separated and turbulent flow features around the building, and RANS provides reliable information when regions of high wind speed and low turbulence are investigated.
Highlights
The prediction of the flow field in a built environment is a rather challenging task
Results show the flow patterns predicted by Reynolds-averaged Navier–Stokes (RANS) and largedynamics eddy simulation (LES), focusing on the different behaviors under smooth and turbulent inflow
Previous experimental tests provided the validation test-case for the roof region [35,45], while at other locations the flow was not measured in experiments; it is reasonable to consider it to be as accurate as is shown by the roof region due to the similar features and high quality of the mesh adopted
Summary
The prediction of the flow field in a built environment is a rather challenging task. This is mostly due to the turbulent structures that occur within the urban environment. Three scales of the signature turbulence may be recognized, which occur due to the separated flow and wake of buildings [1,2]. The importance of correctly estimating and understanding the wind patterns around buildings is evident for many engineering applications in the urban environment.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
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 call