Experimental study on wind characteristics and prediction of mean wind profile over complex heterogeneous terrain

Abstract

This study investigates the impact of complex heterogeneous terrain on mean wind speed and turbulence intensity, highlighting the significance of terrain configuration in the wind loading on buildings and airflow over urban areas. Extensive wind tunnel tests were conducted for 60 different roughness configurations, obtained by processing aerial images across the United States. The study makes two main contributions. First, a model was proposed to predict mean wind profiles, using the morphological information of complex heterogeneous terrain. The Deaves and Harris model was utilized along with a novel algorithm for the automatic characterization of roughness transitions. The proposed model exhibited less than 2% average prediction error compared to the measured wind speed. Second, the study investigated the impact of terrain complexity on near-surface wind characteristics. By comparing the experimental results with those obtained from a homogeneous terrain with a similar roughness length, we quantified the potential errors that may arise when assuming a homogeneous terrain for wind speed assessment. It was observed that increasing variability in roughness length led to a decrease in mean wind speed and an increase in turbulence intensity. The influence of terrain complexity, however, was found to be secondary compared to roughness length. Consequently, the relationships between terrain complexity and wind characteristics were quantified, and a simplified model was proposed.