Numerical simulation of flows around broad-leaf trees

A numerical model was established to predict flow past discrete broad-leaf trees so as to provide a handy tool for pedestrian wind analysis during the preliminary design stage for local wind environments. In the study, a tree factor was proposed to reflect the effect due to the existence of the trees. Besides the applications of numerical computations in flow analysis, wind tunnel measurements were also performed to guide and confirm the numerical simulations. Results showed that the calibrated tree factor generally increased with increases of the volume ratio and horizontal thickness of the tree body. Based on the calibrated relationship of the tree factor, finally, additional numerical computations were performed to simulate flow past an isolated tree and dual trees in a tandem and a side-by-side arrangement. The predicted downstream wind velocity profiles appeared in good agreements with the measurement results.