Combined wind tunnel and CFD analysis for indoor airflow prediction of wind-driven cross ventilation

Abstract

This study presents a method for predicting wind-induced cross ventilation using wind tunnel testing coupled with Computational Fluid Dynamics (CFD). First, in a boundary layer wind tunnel, facade pressures near openings of a test house were recorded for multiple incident wind angles using a 1:25 scale building model. The wind tunnel pressure data was then converted into appropriate boundary conditions for an indoor CFD airflow model of the test house. Both steady state and transient CFD simulations were conducted to capture averaged flow and instantaneous flow rates of the cross ventilation flow. The CFD simulation result was compared to the full scale experimental data from a previous study. The steady state result shows that it is possible for this combined wind tunnel-CFD method to predict the averaged cross ventilation through small openings adequately. Similarly, the transient result shows the fluctuation of the flow at the openings could be predicted at a frequency as high as 0.1 Hz. As many buildings design processes now include wind tunnel testing as a part of structural analysis, this proposed method could utilize the wind tunnel pressure data for assessments of a building's cross ventilation potential.