Application of CFD simulations of wind-driven rain (WDR) on the new roof extension for San Mames new football stadium

The new San Mames Stadium, recently awarded in the World Architecture Festival as the best Sports building completed in 2015, is the new home of football team Athletic Club of Bilbao. After the new stadium was finished, IDOM was commissioned by the Club to assess potential upgrades in the roof with the aim of improving the spectators’ comfort on rainy days. The selected solution, the erection of a cable-roof extension which increases the roof spans by 13–23m, was eventually carried out during the summer break of 2016. This paper describes the assessment process carried out by IDOM, focusing on the 3D Computational Fluid Dynamics (CFD) simulations of wind flow and Wind-Driven Rain (WDR) for the original stadium roof and for different roof alternatives. The performance of each potential alternative is evaluated and compared under different rain events. The wind-flow patterns are determined by steady-state RANS simulations, whereas the WDR trajectories are estimated by means of Lagrangian particle tracking. Field measurements of wind velocities and wetting patterns on the stands were also taken during the whole assessment process in order to correlate the results obtained from the CFD analyses. Furthermore, some wind tunnel testing were also performed in parallel in order to assess, in a qualitative way, the effects of each potential alternative on the wind-flow patterns and compare them with the CFD results.