防风栅透风间隙配置对防风功效之研究Study on the - 水土保持学系.PDF

防風柵透風間隙配置對防風功效之研究 (1) (2) 黃隆明 楊清華 摘 要 本研究的目的在以數值方法，模擬防風柵透風間隙變化之鄰近流場，以探討防風柵之防風 功效。研究中以四組透風率為 30%之防風柵從事風洞實驗，進而對數值模式參數加以驗證、比 較、探討與分析。風場計算係採用微可壓縮流配合大渦模擬及有限體積法，以模擬防風柵之鄰 近紊流流場。綜合研究所得結果如下：1. 防風柵間隙均勻配置時，間隙大者較間隙小者更具防 風功效，其保護指數 (P.I.) 達24.83H2 。2. 防風柵間隙不均勻配置時，若間隙之配置從底部至頂部 逐漸加密，可獲得較佳之防風功效，保護指數達 27.13H2 。3. 防風柵間隙最佳化之配置，由底 部 0.5H 範圍內將透風率固定為 30% ，而頂部0.5H 範圍內透風率設定為零，保護指數高達 30.91 H2 ，其防風功效較間隙均勻配置提高約38% 。 關鍵詞( ：防風柵、透風間隙、大渦模擬) Study on the Effect of Wind Reduction by the Ventilation Interval of Windbreak Fence Long-Ming Huang Associate Professor, Department of Soil and Water Conservation, National Chung Hsing University, Taichung, Taiwan, R.O.C. Ching-hua YANG Graduate Student, Department of Soil and Water Conservation, National Chung Hsing University, Taichung, Taiwan, R.O.C. ABSTRACT The purpose of this study was to explore the effect of ventilation interval change by numerical method, which simulated the flow field around windbreak fence. The wind tunnel experiments by four windbreak fences with 30﹪penetration were performed to verify, compare and analyze the parameters of numerical model. Additionally, the computational code used is based on a weakly-compressible-flow method, together with a large-eddy-simulation and finite volume method technique is applied to account for the turbulence effect in the flow. The results of this study were as follows: 1. When the ventilation interval of the windbreak fence is distributed evenly, the larger interval leads to a bett