半圓柱形溫室風壓係數之實驗研究

Experimental Study of Pressure Distribution on Semi-Circular Greenhouses

朱佳仁(Chia-Ren Chu) ； 林坦誼(Tan-Yi Lin) ； 楊智凱(Chih-Kai Yang) ； 劉明怡(Ming-I Liu)

《農業工程學報》 62卷3期 (2016/09) Pp. 63-73

https://doi.org/10.29974/JTAE.201609_62(3).0006

摘要

本研究使用風洞實驗研究半圓柱形隧道式溫室的風力負載，實驗入流流況為紊流邊界層流，在不同風向角下，利用高頻率的壓力掃描計量測單棟、二連棟與三連棟半圓柱溫室表面風壓的分佈及瞬間變化，再用甘保機率分佈計算極值風壓，並探討室外紊流強度與陣風因子的關係，以計算建築物的最大風載。研究結果發現：最大負壓皆發生在溫室頂部，風向角22.5°的最大負壓大於風向角0°時的最大負壓，且實驗量測得之溫室外牆的時間平均風壓係數符合「建築物耐風設計規範及解說」(2015)所建議的風壓係數，但耐風設計規範(2015)所建議之陣風因子偏小，無法承受瞬間發生的極值風壓，建議增大陣風因子。本研究之成果可提供半圓柱形溫室的耐風結構設計之用，亦有助於吾人對圓形物體上風壓分佈、分離點及極值風壓的瞭解。

關鍵字

溫室 ； 半圓柱形屋頂 ； 風壓係數 ； 風力負載 ； 風洞實驗

並列摘要

This study uses wind tunnel experiments to investigate the pressure distribution and wind load of semi-circular greenhouses. The instantaneous pressures on the surface of the greenhouse are measured by a multi-channel pressure scanner under different wind directions and arrangements. The experimental results showed that when the time-averaged pressure coefficient of oblique wind (wind direction 22.5°) is larger than that of wind direction normal to the ridge line (wind direction 0°). In addition, the peak pressure is several times larger than the time-average pressure, and the gust effect factor suggested by the Wind Resistance Design Code of Taiwan is not sufficient to protect the semi-circular greenhouses against the peak pressure caused by the turbulent wind. The results of this study not only facilitate a better understanding of the peak pressure around circular-bodies, but also to provide the needed information for the structural design of the arch-roof greenhouses.

並列關鍵字

Greenhouse ； Arch roof ； Pressure coefficient ； Wind load ； Wind tunnel experiment