Natural upward cross-ventilation potential of a leeward sawtooth roof for a single zone building model

The ventilation potential of four leeward sawtooth roof shapes (B1, C1, D1 and E1) is evaluated under normal wind incidence angle (θ = 0°). 3D Reynolds-Averaged Navier-Stokes (RANS) Computational Fluid Dynamics (CFD) simulations are performed in combination with five turbulence models and the numerical model is validated with Particle Image Velocimetry (PIV) data from literature. The volume flow rate (m3/s) and the indoor air velocity (m/s) in the occupancy zone (between 0.60 m and 1.70 m height) are analysed. The results show and confirm the hypothesis that a leeward sawtooth roof shape has a considerable potential to improve the volume flow rate and the indoor air velocity. For a normal incidence angle (θ = 0°), the leeward sawtooth roof model D1 yields the highest increase in volume flow rate: 19.6% higher than obtained by the reference leeward sawtooth roof. However, other leeward sawtooth roof shapes and wind incidence angles should be evaluated for a better understanding of the cross-ventilation potential of leeward sawtooth roof buildings.