Internal Airflow in an Atrium

Description

This project models the external airflow around a building atrium using ANSYS Fluent. Atriums—rooted in Roman architecture and now often multi-story with glazed roofs—rely on the greenhouse and chimney effects for daylight and natural ventilation, and analyzing the wind around them is the first step in designing them well. Here, an 8 m/s horizontal wind flows across the atrium walls, generating high-pressure, separation, recirculation, and acceleration zones typical of bluff-body flow.

Methodology

The 3D external-flow domain (3.35 m × 2.21 m × 3.9 m) is built around the structure in Design Modeler. Meshing produces an unstructured grid of ~1,950,000 elements, locally refined near the building walls to resolve the boundary layer. A pressure-based, steady-state solver is used with the RNG k-ε model and standard wall functions; boundary conditions are an 8 m/s velocity inlet, a 0 Pa gauge-pressure outlet, and stationary walls, with SIMPLE coupling and second-order pressure and momentum discretization.

Conclusion

The simulation examines pressure and velocity distributions and the overall airflow behavior around the atrium. Outputs include 2D/3D contours of pressure and velocity, pathlines, and velocity vectors on the XY plane, along with the pressure distribution over the wall surfaces—enabling identification of stagnation, separation, and recirculation zones relevant to façade design, wind comfort, and structural wind loading.