近年來，為解決能源危機問題，風機之相關研究正蓬勃發展。本研究使用FLUENT套裝軟體模擬直立葉片式垂直軸風機（Straight-Bladed Vertical Axis Wind Turbine, VAWT）流場，探討其氣動力、噪音之現象。利用SIMPLEC/QUICK之數值方法、紊流模型與分離渦流模擬法（Detached Eddy Simulation, DES）在四邊形/三角形網格上求解非穩態不可壓縮納維史托克方程式（Navier-Stokes Equation），並採用聲場模型（Ffowcs Williams and Hawkings Equation, FW-H）計算流場中之噪音分貝值。首先進行葉片翼型為NACA0012之風機流場模擬，以了解網格建構與軟體內部參數設定之影響。接著計算葉片翼型為NACA0015之風機流場，將所得之效率值與實驗值比較以評估本數值模擬。為了解紊流模型與DES特性，對葉片翼型為NACA0018之風機流場進行模擬並與相關之數值解與實驗值比較。在音場模擬方面，首先計算自由流通過圓柱之噪音分貝值。接著進行葉片翼型為NACA0018之風機流場與聲場模擬，探討分貝值隨風機半徑倍數距離變化關係。藉由本文之研究可了解在操作FLUENT時，其網格、流場、邊界條件與參數之設定，並利用上述之模擬結果以探討風機氣動效率、噪音源與改善方法。

In recent years, research of Vertical Axis Wind Turbine(VAWT) is booming in order to solve the energy crisis. Software package（FLUENT）is used in this thesis to simulate flow field of Straight-Bladed VAWT for studying the aerodynamic efficiency and noise. SIMPLEC / QUICK numerical methods, turbulence model and Detached-Eddy-Simulation model are used to solve unsteady incompressible Navier-Stokes Equation on the quadrilateral / triangular grid and then calculated decibel value of acoustic field with FW-H equation. Three different blade profile types are under inspect respectively: (1)NACA0012 for mesh construction and parameter setting; (2)NACA0015 for estimating the simulation with experimental/numerical efficiency; (3)NACA0018 for observing the characteristic difference between DES and turbulent model. For further investigate the decibel value of noise, we simulate acoustic field of a cylinder with FW-H equation. Finally, numerical simulations of flow field and acoustic field are carried out with NACA0018 to research the relation between dB value and radius of wind turbine. In the end, we summarized above argument to provide high reliability of operation setting about grid, flow field, boundary conditions and parameters for wind turbine simulation, in addition discussed improvement in aerodynamic efficiency and noise source.

參考文獻
[1] A. Laneville, and P. Vittecoq, “Dynamic Stall: The Case of the Vertical Axis Wind Turbine.” ASME, Vol. 108,1986.
[2] Akiyoshi Iida, and Akisato Mizuno, “Numerical Simulation of Aerodynamic Noise Radiated form Vertical Axis Wind Turbines.” Proceedings of the 18 International Congress on Acoustics, 2004, CD-ROM.
[3] Ouahiba Guerri, and Anas Sakout, “Simulations of the Fluid Flow around a rotating Vertical Axis Wind Turbine.” Wind Engineering, Vol 31, 2007, pp. 149-163.
[4] Akiyoshi Iida, and Keiichi Kato, “Numerical Simulation of Unsteady Flow and Aerodynamic Performance of Vertical Axis Wind Turbines with LES.” 16th Australasian Fluid Mechanics Conference
Crown Plaza, Gold Coast, Australia.2-7 December 2007.
[5] Carlos Simao Ferreira, and Gerard van Bussel, “2D CFD simulation of dynamic stall on a vertical axis wind turbine: verification and validation with PIV measurements.” AIAA, 2007.
[6] Mazharul Islam, and David S-K. Ting, “Desirable Airfoil Features for Smaller-Capacity Straight-Bladed VAWT.” Wind Engineering, Vol.31, 2007, pp. 165-196.
[7] Mazharul Islam, and David S-K. Ting, “Design of a Special-purpose Airfoil for Smaller-Capacity Straight-Bladed VAWT.” Wind Engineering, Vol.31, 2007, pp. 401-424.
[8] Mazharul Islam, and David S-K. Ting, “Aerodynamic models for Darrieus-type straight-bladed vertical axis wind turbines. ”Renewable and Sustainable Energy Reviews, 2008.
[9] Mazharul Islam, and Amir Fartaj, “Analysis of the Design Parameters related to a Fixed-pitch Straight-Bladed Vertical Axis Wind Turbine.” Wind Engineering, Vol.32, 2008, pp. 491-507.
[10] Sylvain Antheaume, and Thierry Maître, “Hydraulic Darrieus turbines efficiency for free fluid flow conditions versus power farms conditions.” Renewable Energy, Vol.33, 2008, pp. 2186-2198.
[11] Amet E., and Maître T., “2D Numerical Simulations of Blade-Vortex Interaction in a Darrieus Turbine.” ASME, Vol.131, 2009.
[12] Manabu TAKAO, and Hideki KUMA, “A Straight-bladed Vertical Axis Wind Turbine with a Directed Guide Vane Row Effect of Guide Vane Geometry on the Performance.” Journal of Thermal Science, Vol.18, 2009, pp. 54-57.
[13] Stefan Oerlemans, and Murray Fisher, “Reduction of Wind Turbine Noise Using Optimized Airfoils and Trailing-Edge Serrations.” AIAA, Vol.47, 2009.
[14] Hongbo Lu., and Yonglin Li., “Parameter Optimization and Numerical Simulation of Vertical-Axis Tidal Turbine.” IEEE, 2010.
[15] Shengmao Li., and Yan Li., “Numerical study on the performance effect of solidity on the straight-bladed vertical axis wind turbine.” IEEE, 2010.
[16] Robert Howell., and Ning Qin., “Wind tunnel and numerical study of a small vertical axis wind turbine.” Renewable Energy, Vol.35, 2010, pp. 412-422.
[17] Yan Li., and Kotaro Tagawa, “Performance effects of attachment on blade on a straight-bladed vertical axis wind turbine.” Current Applied Physics, 2010, pp. 335-338.
[18] Yan Li., and Kotaro Tagawa, “Computer Simulation on the Icing Accretions on a Static Straight Blade Used for the Vertical Axis Wind Turbine.” IEEE, Vol.4, 2010.
[19] S.J. Kooiman, and S.W. Tullis, “Response of a Vertical Axis Wind Turbine to Time Varying Wind Conditions found within the Urban Environment.” Wind Engineering, Vol.34, 2010, pp. 389-401.
[20] In Seong Hwang, and Seung Yong Min, “Efficiency Improvement of a New Vertical Axis Wind Turbine by Individual Active Control of Blade Motion.” Smart Structures and Materials, Vol.6173, 2006, pp. 316-323.
[21] R. Gupta, and A. Biswas, “Comparative study of a three-bucket Savonius rotor with a combined three-bucket Savonius–three-bladed Darrieus rotor.” Renewable Energy, 2008, pp. 1974-1981.
[22] Agnimitra Biswas, and Rajat Gupta, “Comparative Study Of A Two-Bladed Airfoil Shaped H-Darrieus Rotor With A Two Straight Bladed H-Darrieus Rotor.” World Renewable Energy Congress, 2008.
[23] RAJAT GUPTA, and BIPLAB KUMAR DEBNATH, “CFD Analysis of Two-Bucket Savonius Rotor Using FLUENT Package.” European Wind Energy, 2009.
[24] Biplab Kumar Debnath, and Agnimitra Biswas, “Computational fluid dynamics analysis of a combined three-bucket Savonius and three-bladed Darrieus rotor at various overlap conditions.” Renewable And Sustainable Energy, 2009.
[25] Rajat Gupta, and Sukanta Roy, “Computational fluid dynamics analysis of a twisted airfoil shaped two-bladed H-Darrieus rotor made from fiberglass reinforced plastic (FRP).” Energy And Environment, Vol.1, 2009, pp. 953-968.
[26] R. Gupta, and B. Agnimitra, “Computational fluid dynamics analysis of a twisted three-bladed H-Darrieus rotor.” Energy And Environment, 2010.
[27] M.H. Mohamed, and G. Janiga, “Optimization of Savonius turbines using an obstacle shielding the returning blade.” Renewable Energy, 2010, pp. 2618-2626.
[28] 謝承翰,“垂直軸風力機扭力與功率的檢測與模擬.”成功大學碩士論
文, 2009.
[29] 王皇仁,“分歧管內氣流之數值研究.”成功大學碩士論文, 2010.
[30] FLUENT 6.3 User's Guide.2006.
[31] 陳廷彰,“風扇噪音分析與有孔平板受風扇噪音激振的聲場分析.”中央大學碩士論文, 2008.
[32] Fluent 6.1 Tutorial Guide., “Aero-Noise Prediction of Flow Across a Circular Cylinder.” Fluent Inc., 2002.
[33] Environment Protection Administration Executive Yuan, R.O.C.
(Taiwan). http://ivy1.epa.gov.tw/noise/BB/B-04-01.htm
[34] World Wind Energy Association, “World Wind Energy Report.” WWEA, 2010.