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標題: Study on the Shelter Effects of Two-Section Windbreak Fences
作者: 歐陽志岳
Chih-Yueh, Ou-Yang
關鍵字: Various intervals;間距配置
出版社: 水土保持學系所
引用: 參考文獻 1. 胡金印,2000,恆春地區農業活動對落山風的調適。國立台灣師範大學地理學系博士論文,第1-2頁。 2. 梁大慶,1999,傾角式防風柵之防風效果研究。國立中興大學水土保持學系博士論文,第3-4、55-58頁。 3. 防災科技研究通訊,九卷2期,1991-04。 4. 黃隆明,1989,防風網形式對防風功效之研究。國立中興大學水土保持研究所碩士論文。第42-43頁。 5. 汪群從、黃榮鑑,1983,大氣邊界層風洞之規劃與設計研究。行政院國家科學委員會研究計劃研究報告,NSC-72-0414-P-001-01,AEWT001。 6. 谷 信輝,1952,防風牆の機能に關する研究,模型防風牆の風洞實驗(との1)。日本農業氣象,7(2):15-17。 7. 谷 信輝,1952,防風牆の機能に關する研究,模型防風牆の風洞實驗(との2)。日本農業氣象,7(2):56-58。 8. 三原義秋、谷 信輝 ,1952,防風牆の機能に關する研究。日本農業氣象,7(2):7-8。 9. Biggs, J. M., 1954, “Wind Load on Truss Bridges,” J. Structural Engg ASCE, Vol. 119, pp.49-71. 10. Cermak, J. E. and Peterka, J. A., 1974, “Simulation of Atmospheric Flows in Short Wind Tunnel Test Sections,” Center for Building Technology, IAT, National Bureau of Standard Was Hington, D. C., June. 11. Counihan , J., 1975 , “Adiabatic Atmospheric Boundary Layers: A Review and Analysis of Data from the Period 1880-1972,” Atmospheric Environment, Vol. 9, pp.871~905. 12. Counihan, J., 1970, “Atmospheric Environment,” Atmospheric Environment, Vol. 4, pp.159~275. 13. Counihan, J., 1973, “Simulation of an Adiabatic Urban Boundary Layer in a Wind Tunnel,” Atmospheric Environment, Vol. 7, pp.673~689. 14. Courant-Friedrichs-Lewy, 1967. 15. Fang, Fuh-Min , 1997, “ On the Flow Around a Vertical Porous Fence, ” J. Wind Engg. And Ind.Aerod.,Vol.67and 68, pp.415-424. 16. Fang, Fuh-Min , Jong,W.D. J.J., 1997, ” Unsteady Turbulent Flow Past Solid Fence, “ J.Hydraulic Engg. , ASCE,,Vol.123, pp.560-565. 17. Kolmogorov, A.N., 1941, “The Local Structure of Turbulence in Incompressible Viscous Fluid for Very Large Reynolds Number,” Doklady An. SSSR, Vol. 30, No. 4, pp.299~303. 18. MacCormack, R.W. , 1969, ” The Effect of Viscosity in Hyper-Velocity Impact Cratering ,” AIAA PAPER, NO.69-354. 19. Nakamura Y. and Ozono , S ., 1984, “ The effect of turbulence on a separated and reattaching flow. “J. Fluid Mech.178,477-490. 20. Prandtl, L., 1925, “Uber die Ausgebildete Turbulenz,” ZAMM 5,pp.136-139. 21. Simiu, E. and R.H. Scanlan, 1986, “Wind Effects on Structure,” John Wiley & Sons, Inc. New York, pp. 39~52. 22. Standen, N. M., 1972 “A Spire Array for Generating Thick Turbulent Shear Layers for Nature Wind Simulation in Wind Tunnels,” Rep. LTRLA-94, National Aeronautical Esblisment, Ottawa, Canada. 23. Smagorinsky, J., 1963, “ General Circulation Experiments with the Primitive Equations ,” Month Weather Review , Vol.93, No.99, pp.99-164. 24. Van, E. J. Karschon, R. Razumova, L. A. and Roberts, G. W., 1964, “Windbreaks and Shelterbelts,” W. M. O. Technical note 59, pp.5-21.
The purpose of this study is to numerically investigate how the various intervals of the two-section windbreak fences will affect the flow of wind around it and set a simulation mode. In order to ensure the accuracy of the numerical simulation, this study employed 2 scaled models for wind tunnel experiments. The fences had a height (H) of 9cm and sectionalized into 2 sections with 4.5cm of height. In addition, the wind tunnel experiment is to use a method of testing and verifying the differences in numerical simulation. In each test, 30% of the windbreak fences will allow ventilation, and we have simulated the test with the Reynolds number (7.2104 ), the thickness of the boundary layer ( 5.33H ), and the n index of the Power Law (0.157).After handling and analyzing the data of the test with the software, we then proved the mode is applicable by confirming and verifying the results. Moreover, seven sets of research cases were chosen to test the numerical simulation to study the impact of flow variation on windbreak effect.
The conclusions of this study are:
1. The difference between two-section type of windbreak and the tradition vertical type depends on the shape variation. The air flow through the upper half grid will be further raised by the air flow through the lower half grid. That will consequently widen the range of low wind speed area, thus will achieve the windbreak effect.
2. The windbreak effect of various intervals of the two-section windbreak fence: In case of the interval of two-section type of windbreak increases, the low wind speed zone in lee side becomes longer, which will increase the protection distance and the windbreak effect near the earth surface. In this study, when the interval equals to 2H, the protection distance reaches its maximum value, which is 1.48 times longer than that of the single windbreak grid. As the interval decrease to H/3, the more the rising air flowing through the lower half grid, the less the air passing through the construction, the reflux area of down-stream is the largest with the best windbreak effect, while the protection index (P.I.) is 1.18 times than that of the single wind-break grid.

1. 兩截式防風柵與傳統直立柵減風差異,主要受外形導流之影響,將越過上半截柵之氣流,進一步受到越過下半截柵氣流的抬升作用,使背風面低風速區的範圍增大,因而提升防風功效。
2. 不同間距配置之防風柵構造物其防風效果:兩截式防風柵之間距加大,背風面之低風速區域愈趨扁長,對於鄰近地表處有愈佳之減風效果,其保護距離越長,本研究中當間距配置為2H時,有最長的保護距離,其值為單道防風柵的1.48倍;在本研究中,當間距為1H時,經下半截防風柵抬昇之氣流愈多,而越過上半截構造物之氣流愈少,使其下游面迴流區形狀最大,防風效果最好,其保護指數(P.I.)為單道防風柵的1.18倍。
其他識別: U0005-2208200614423700
Appears in Collections:水土保持學系

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