本研究利用風洞實驗來探討一個矩形建築物位於邊界層流中周遭風場流況，研究的目的在於探討建築物風場之影響區域與建築物寬度及高度對風場之影響。實驗是在中央大學的大型邊界層風洞中進行，並使用熱線測速儀配合裂膜探針來量測風場速度，以探討迴流區之流況。實驗結果顯示：（1）?隨建築物寬度增加，建築物前方且Z/H = 0 ~ 1 內之水平風速的減速現象亦增加，一倍柱體高以內建築物上方的加速趨勢也隨之增加，後方流場在寬高比W/H = 1與2之兩組在X/H = 0.5 ~ 4 ，Z/H = 0 ~ 1 之間為低風速區，寬高比W/H = 4與28之兩組建築物後方風速影響範圍在X/H > 5；?寬度改變對風速變化範圍向下游延伸，但高度改變卻不明顯；（2）由建築物前緣邊角發展出之分離剪力層有最大雷諾剪應力與最大紊流動能；（3）建築物後方並無明顯之渦流逸散，無法觀測出逸散頻率；（4）紊流動能消散率隨建築物加寬或加高，影響範圍逐漸變大。 The flow field around surface-mounted obstacles were experimentally investigated in this study. The experiments were conducted in large-scale wind tunnel. The turbulent velocity, kinetic energy, dissipation rate and vorticity distribution were measured by a split-film thermal anemometer and an automatic transversing system. The influence of the aspect ratio of obstacle was systematically studied in this research. The experimental results reveal that the separated shear layer on the top of the obstacle grows stronger as the width and height ratio increases. Also, the wake flow of the obstacle does not have periodic vortex shedding like that of cylindrical wake.
