Aerodynamic optimisation of sports stadiums towards wind comfort

The aim of this work was to investigate the aerodynamic performance of sports stadiums located in the built environment and conduct a design optimisation study to
improve the wind comfort conditions for both players and spectators. A 1:300 scale semi-open stadium model was assessed with combined Atmospheric Boundary Layer (ABL) wind tunnel experimentation and Computational Fluid Dynamics (CFD) techniques against pressure and velocity distribution patterns in both interior and exterior areas of the stadium bowl. The validation of the numeric analysis was performed with the experimental results of pressure coefficients.
The aerodynamic performance analysis compared two impinging wind angles (0o and 90o) and two building envelope porosities, defined by the existence of an
elevated and non-elevated roof configuration. The results indicated that the wind direction caused small differentiations on the developed wind distribution patterns, with the wind angle of 90o generating smaller negative pressures in both interior and exterior stadium surfaces. Further analysis of the air velocity distribution results indicated that the provision of a horizontal ventilation opening between the roof and
the upper spectator tiers substantially improves the airflow distribution for the benefit of spectators, but induces up to 25 % higher velocities at the centre of the
pitch level.
Parametric studies were performed to evaluate the impact of the roof geometry changes on the developed wind comfort conditions for the players and the spectators.
By employing coupled CFD-Response Surface Methodology (RSM) techniques, it was found that the wind speeds and the flow homogeneity at the stadium bowl are more susceptible to firstly the roof height and secondly the roof radius. Finally, the generated response surfaces formed the basis for the conduction of a multi-objective
optimisation study, which revealed that a drastic reduction of the roof height and the roof radius by 96.9 % and 50 % respectively may reduce the wind speeds and the flow heterogeneity up to 37 % and 49.6 % in the occupied areas.