CFD Study of Cross-Ventilation in an Elongated Building with a Convex Sawtooth Roof: Single-Span vs. Double-Span

摘要

The ventilation flow in an elongated low-rise building with three convex roof geometries is analyzed for a normal wind direction. The three geometries consist of one single-span geometry (E2) and two double-span geometries: E2x2_OR1 and E2x2_OR 0.5, with similar and lower inlet-outlet opening ratio (OR) than E2, respectively. 3D steady Reynolds-averaged Navier-Stokes Computational Fluid Dynamics (CFD) simulations are employed. The computational model is based on a grid-sensitivity analysis and validation with Particle Image Velocimetry measurements from literature. The double-span geometry E2x2_OR1 results in a 12% lower volume flow rate than single-span geometry E2. However, geometry E2x2_OR 0.5 (same roof geometry; larger outlet opening area) results in a 22.5% higher flow rate than for single-span geometry E2. The opening ratio and the internal roof geometry near the outlet opening appear to play an important role in the ventilation of the building, as indicated by the differences between E2x2_OR0.5 and E2x2_OR1.