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.

A scaffolding system model at one side of the exterior surfaces of a square building was set in the wind tunnel to measure the wind forces on the system in various oncoming-flow directions. The scaffolding system with additional clad sheets at three porosity ratios was tested to examine its wind load effect. Moreover, numerical computations were performed to examine the wind flow in the region between the building surface and the impermeable clad sheet. Results show that a decrease of screen porosity generally promotes varies wind force with the oncoming-flow direction variation. As the scaffolding system is at the windward side of the building, a maximum total push-in force occurs. When the system is parallel to the oncoming-flow direction, the total pull-out force becomes maximum. The cross-sectional maximum and minimum net pressure values mostly occur near the edge or the corner of the scaffolding system. Among all oncoming-flow directions, finally, cross-sectional large wind speeds usually occur at the upstream upper corner in the scaffolding system. The most critical situation that endangers the safety of construction workers due to the occurrence of local gust wind can happen when the oncoming-flow direction angle is within the range of 60 to 90 degrees.

The interference effect is one of the difficult topics in wind engineering research themes. Enormous publications have been made to understand its whole picture qualitatively and quantitatively in the past several decades. However, rare results focused on the interference effects of the neighboring building located downstream. This study intends to investigate several mentioned downstream interference effects based on the high-frequency-force-balance tests. Four different cross-sections are selected to understand how the adjacent building’s appearance interferes with the square principal building. Results show that the interference effects induced by the downstream neighboring buildings can be categorized into two locations – the oblique-downwind location and the downwind location. The oblique-downwind interference effect generates two different motion shapes of the principal building, including the inclined hollow elliptical motion from the two-directional resonant vibration and the standing elliptical motion from one-directional resonance. The downwind interference effect generates a similar one-directional resonance. Several force spectrum examples are given in this study to illustrate how the oblique-downwind interference effect mechanism forms at a specific distance and reduced velocity. In addition, the results from the augmented experiment with more combinations of two buildings suggest more efforts are necessary for inspiring the phenomenon of an inclined hollow elliptical motion.