Shelter Effect of Pedestrian Wind behind Row Trees in a Line Arrangement

Flow past a single-line arrangement of evenly-spaced row trees, in an open territory, was numerically simulated under the action of a boundary-layer type of oncoming flow, with a strength of “strong breeze”, based on the Beaufort scale. By selecting Koelreuteria henryi as the demonstrated tree species, the spatial wind speed variations behind row trees at the pedestrian level, at various tree heights and tree spaces, were analyzed to investigate the corresponding downstream shelter effects from a systematic basis. Based on the results of the analyses, the tendency of stream-wise wind speed variations behind the row trees was presented so as to provide additional insights into row-tree planning for protection against ground wind. Moreover, in other cases of row trees with similar crown shapes and properties, resulting flow fields for various tree heights and tree spaces can provide referable quantitative information, which can be readily used to conduct tentative shelter effect assessments and pedestrian comfort evaluations in a preliminary planning stage.