Assessment of the aerodynamic performance of unconventional building shapes using 3D steady RANS with SST k-ω turbulence model

As more high-rise buildings are being built with unconventional shapes for improved aerodynamic performance and architectural appeal, Computational Fluid Dynamics (CFD) offers a potential means for aerodynamic investigation of these buildings. Most practitioners in the structural engineering industry do not have sufficient computational resources for the transient analyses (e.g. with Large-Eddy Simulation) of wind flow around structures. For this reason, Reynolds-Averaged Navier-Stokes (RANS) approaches have the potential to be widely used in the industry. Although steady RANS provides no information on the peak pressures, it has, in recent years, attracted a renewed interest as an affordable tool to complement other hybrid or surrogate models for computationally tedious objectives such as aerodynamic shape optimization. Using a consistent set of CFD settings based on the evolving RANS guidelines, the present study aims to assess steady RANS for its capability in reproducing mean wind loads on a set of 7 unconventional building shapes across 10 angles of wind incidence (α). The simulations show that RANS tends to overestimate the windward pressure (by ∼ 0.12) and underestimate the magnitude of leeward pressure (by ∼ 0.25), but predicts mean moment coefficients comparable to wind tunnel measurements (within ∼ 0.09) for most of the building geometries.