Erosion of limestone building surfaces caused by wind-driven rain: 2. Numerical modeling

Wind-driven rain and its effect on surface stone deterioration have been studied at the Cathedral of Learning, a tall limestone building on the University of Pittsburgh campus. In this second paper of the series, a numerical method based on computational fluid dynamics techniques is used to predict wind-driven rain on the Cathedral. Three steps are involved: computing the airflow field around the building, determining raindrop trajectories, and estimating total rain impingement based on meteorological data. Results are expressed in terms of the Catch Ratio, the flux of rain on the building walls divided by the flux of rain on the ground. The method is applied to 94 rain events during the measurement period. Results show good agreement with field data, indicating that the method can provide reasonable predictions of wind-driven rain.