Description

This project simulates airflow and natural ventilation in an octagonal windcatcher using ANSYS Fluent. Windcatchers are tall rooftop towers that capture ambient wind to flush out warm, polluted indoor air and drive fresh air into the building. Their internal walls and channels trap and guide the flow downward from upper intake panels into the occupied space below. The windcatcher sits in a large open-domain environment with a horizontal wind of 10 m/s at atmospheric pressure.

The geometry is created in ANSYS DesignModeler and meshed in ANSYS Meshing with an unstructured grid of 2,332,185 cells.

Method

This is a fluid-only analysis (no heat transfer). The internal layout above the windcatcher includes barrier surfaces so that some upper inlets face the wind directly while others are shielded. This arrangement establishes a pressure differential: windward openings promote inflow/traction, while leeward sides promote suction, driving circulation through the windcatcher shaft and the room beneath.

Results

Post-processing provides velocity and pressure contours, plus velocity vectors and pathlines. The windward side of the windcatcher shows higher pressure than the leeward side. Flow visualizations confirm that air enters via the top panels, is guided and trapped by interior walls, then descends and discharges through lower panels into the interior—indicating the windcatcher operates as intended.