10.4122/1.1000001018
Blocken, Bert
Bert
Blocken
b.j.e.blocken@tue.nl
Persoon, Jan
Jan
Persoon
Van Hooff, Twan
Twan
Van Hooff
Carmeliet, Jan
Jan
Carmeliet
De Wit, Martin
Martin
De Wit
Persoon, Jan
Jan
Persoon
Spectators’ comfort in sports stadia: impact of roof geometry on wind-driven rain shelter
8th Symposium on Building Physics in the Nordic Countries
2008
2008
Apart from sports purposes, stadia are also increasingly being used for concerts and
other events with large spectator attendance. The main aspect for spectator comfort
in open stadia is protection from wind and rain. In the design of many existing
stadia however, rain shelter has insufficiently been taken into account because most
roofs have been designed with vertical rainfall in mind, while no consideration has
been given to the possibility of rain being blown onto the stands and spectators by
wind (wind-driven rain). Adequate rain shelter should be addressed during the design
stage of new sports and football stadia. Currently however, almost no information or
guidelines on this matter are available. This paper presents an investigation of the
impact of roof geometry on rain shelter. 2D Computational Fluid Dynamics (CFD)
simulations and Lagrangian particle tracking are performed to analyse the wind flow
pattern and rainfall distribution in seven generic stadium configurations and to
assess the performance of each roof type. Although most existing stadium roofs are
built with a light to medium upward slope towards the field, the analysis indicates
that roofs with a downward slope of 13° provide significantly better rain shelter.
This paper will demonstrate that the reason is not only the well-known trigonometric
shielding effect. This effect refers to the rain shelter that can theoretically be
obtained by assuming that raindrop trajectories are straight lines. This study will
show that, in addition to the trigonometric shielding effect, downward sloping roofs
restrict the extent of the primary vortex in the stadium and generate a sufficiently
strong counter-rotating secondary vortex below the roof that sweeps the rain away
from the stands. This specific feature appears to occur only for roofs with a
sufficiently large downward slope. As a result, downward sloping roofs are clearly
superior in terms of rain shelter compared to traditional roof types with an upward
slope towards the field.