摘 要 本研究以風洞實驗的方式來探討邊界層流中低矮建築物表面風壓的分佈情形，實驗條件包括三種不同屋頂角度（15度、20度、30度）的模型。壓力量測使用電子式壓力掃描器可同時量測多個位置的瞬時壓力，由實驗結果可進而計算建築物表面的平均、擾動和最大壓力分佈。實驗結果顯示迎風面牆與背風面牆的平均壓力會隨屋頂角度的增加而增加；迎風面屋頂會由15度的負壓轉變為30度的正壓，20度則同時受正、負壓的作用，此結果接近前人研究所得之臨界角度；背風面屋頂的壓力和擾動壓力隨屋頂的增加而減少。 本研究以卓勇志(2001)所建議之最大壓力的前10%之壓力係數Cp10作為設計風壓係數，Cp10可用平均壓力係數Cp，加上擾動壓力係數Cprms與尖峰因子g10的乘積表示。尖峰因子不受建築物幾何外型及量測位置的影響，g10約為1.23，此結果可有效降低工程設計成本和簡化設計難度。本研究並以統計的方法分析各點所得的擾動風壓，發現迎風面牆和屋頂的擾動風壓會接近高斯機率函數，然而背風面牆和屋頂的擾動風壓會偏離高斯函數。本研究之結果可作為相關研究之參考，並提供相關工程改善時的建議。 Abstract This study experimentally investigates the pressure distribution on the surface of low-rise buildings with different roof angle (15o,20o and 30o). The experiments were carried out in an atmospheric boundary layer wind tunnel. Instantaneous fluctuating wind pressures were measured by an electronic pressure scanner. Based on the pressure measurement, the distributions of mean, rms Cprms and peak pressure Cpp can be calculated. It was found that the mean pressure coefficient on the front roof surface change from negative to positive while the roof angle change from 15 o to 30o. The critical angle is close to 20o, which is in good agreement with previous studies. The pressure coefficient, Cp10, could be calculated by the formula, Cp10 = Cp + g10?Cprms, where the peak factor g10 = 1.23, which is independent of the building shape and position. Experimental results also revealed that the probability of pressure fluctuations on the front surface are closed to the Gaussian distribution. On the other hand, the leeward side was skewed and did not necessary follow Gaussian distribution.
