Mean and turbulent wind characteristics around a high-rise elevated building with curved cross-sections : wind tunnel experiments and numerical simulations

Abstract

Mean and turbulence wind characteristics of a C-shaped elevated building at various incident wind directions were investigated through a wind tunnel experiment and Computational Fluid Dynamics (CFD). The wind tunnel experiment measured the time-averaged velocity field and the turbulent statistics around the building, providing a reliable database for validation. The simulation employed both the Reynolds-averaged Navier-Stokes (RANS) equations, including the Realizable k−ε model (RLZ), and Renormalization group k−ε model (RNG), the k−ω shear stress transport (SST) model, as well as Large Eddy Simulation (LES) with Wall-Adapting Local Eddy-Viscosity model (WALE). These were compared against the measurement results obtained from the wind tunnel. A quantitative investigation compared the impact of an elevated section on pedestrian wind environments by studying a C-shaped elevated building and a non-elevated building. The RANS models reasonably predicted the low wind velocities in the upstream area but underpredicted the corner and downstream wind velocities while overpredicting the jet flow region through the elevated column. The LES model showed great agreement with the wind tunnel experiment results and successfully captured the areas with large turbulence kinetic energy (TKE) between the elevated columns, whereas the RANS model was unable to resolve these regions accurately. The use of a larger time step in LES may result in the underestimation of high TKE regions around the C-shaped building. The vortex shedding phenomenon around an elevated C-shaped building was more complex compared to that around a non-elevated building, as evidenced by the broader range of Strouhal numbers observed around the elevated structure.