Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/33288
標題: Study on the Effect of Wind Reduction by the Successive Windbreak Fence
連續式防風柵之防風功效研究
作者: 張書豪
HAO, CHANG SHU
關鍵字: 防風柵
出版社: 水土保持學系
摘要: 
本研究的目的在以數值方法,模擬連續式防風柵之鄰近流場,以探討防風柵之防風功效。研究中並從事風洞實驗,俾與數值模式參數進行驗證、比較、探討與分析。為了要獲取連續式防風柵初步設計的參考資料,研究中系統化地配置不同防風柵列數及間距,以從事流場特性與防風面積的比較。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。
研究結果發現,於一道式構造物的情況中,孔隙率為30%的防風柵比防風牆有較佳的防風功效;於兩道式防風柵時,在間距區內,防風功效以間距16H至18H最佳(H為防風柵高),但在第二道防風柵下游區,以本研究個案而言,則以間距配置為22H最佳;於三道式防風柵時,在間距區內,以前間距16H、後間距12H前長後短之配置最具防風功效,但在第三道防風柵下游區,則間距配置以前短後長者為佳。最後,在本研究個案中,三道式防風柵採用等間距14H及16H之配置,其防風功效最差。

The purpose of this study is to investigate numerically the flows around successive windbreak fences so as to explore general flow behavior and the effect of wind reduction. Moreover, verifications and analyses of the results of wind tunnel experiments were performed to compare with the predictions and to guide the numerical parameters. By varying the number of the fence series and the distances among them, flow simulations were carried out on a systematic basis to obtain general design guidelines of the successive windbreak fence. The results were then analyzed to compare the flow characteristics and wind reduction area.
In the numerical computations, a weakly compressible method, based on a finite volume approach, were adopted. To reflect the turbulence nature of the flow, a large eddy simulation with a subgrid-scale turbulence model were applied.
The conclusions are drawn as follows:
1. Based on the sheltered area as defined, the windbreak fence with a porosity of 30% leads to a better wind reduction effect than that of a solid wall.
2. In the case of two-series windbreak fences, a better wind reduction effect between the fences is obtained when the distance between the fences is within 16 to 18 times of the fence height. Moreover, in the studied cases, the best effect in the area behind the second fence is obtained when the fence distance is set as 22 times of the fence height.
3. For three-series windbreak fences, the best combinations is that the distances among the fences are set respectively as 16 and 12 times of the fence height. As the area behind the third fence is of concern, the best result is obtained when the gaps of the fences are set as a short-long type. On the other hand, among the studied cases, the worst wind reduction effect appears when the gap distances are the same (14H or 16H, H being the fence height).
URI: http://hdl.handle.net/11455/33288
Appears in Collections:水土保持學系

Show full item record
 

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.