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 For calculating how the wind turbine blades interfere with the radar, we use radar cross section. Because the blades are irregular, we start from incident wave and scatter wave to derive a surface integral to evaluate RCS. In the case of a circular cylinder, we use curvilinear patches to decompose the cylinder surface. The different results between using the surface integral and using cylinder formula are close. Nevertheless, the surface integral method takes a lot of time.To accelerate the calculation, if is ignored, the surface integral can be simplified. Due to no twisting in the circular cylinder, this approach yields results very close to that by using the analytical formula.However, the wind turbine blade patches exhibit twisting. So cannot be ignored. We use the Boersma’s polynomial to expand the Fresnel function, and this results in 27 1D integrals. For these 1D integrals, the integration by part method is utilized to derive recurrence relations, which can efficiently evaluate these 1D integrals. Comparisons are made between results by the recurrence method and those by direct numerical integrations.Unfortunately, the recurrence approach sometimes gives rise to divergently erroneous results. Effort has been made to reduce the errors by setting parameter thresholds to determine what alternative to be used to improve the results. Although the errors are less, the resulting values still does not make any sense comparing with those accurate results. Because of this discrepancy, the proposed accelerating method fails to provide accurate RCS at this time. With recurrence formulae being correct, more tests should be conducted in order to find the real cause of numerical errors. Therefore we resort to the original surface integral in calculating RCS, which has been applied for the wind turbine blade. The obtained result is compared favorably with that by the commercial software, FEKO.Keywords: blades of wind turbines、RCS、PATRAN、quadratic curvilinear patches.
 目次摘 要 IAbstract II目次 III圖目次 IV表目錄 V第一章 序論 11.1 研究動機與目的 11.2 文獻回顧 11.3 章節概要 2第二章 風力發電機RCS計算 32.1 扇葉模型網格化 32.2 風力發電機扇葉RCS 112.3 Matlab程式驗證 132.4考慮 的計算方式 182.5 二維積分的計算方式 22第三章 結論 25參考文獻 27附錄1 28附錄2 30附錄3 33附錄4 34
 [1] H.S. Dabis and R.J. Chignell, “Wind Turbine Electromagnetic Scatter Modeling Using Physical Optics Techniques,” Renewable Energy 16, pp. 882-887, 1999[2] I Angulo, O. Grande, D. Jenn, D. Guerra and D. de la Vega, “Estimating Reflectivity Values From Wind Turbines For Analyzing The Potential Impact On Weather Radar Services,” Atmos. Meas. Tech., 8, 2183-2193, 2015[3] J. Pinto, J. C. G. Matthews and G. C. Sarno, “Stealth technology for wind turbines,” IET Radar, Sonar and Navigation, vol. 4, iss. 1, pp. 126-133, 2010[4] Spencer Stromberg,“Wind Turbine Blade,” http://grabcad.com/library /wind-turbine-blade,27 Nov.[5] A. M. Woods, K. D. Carmody and C. D. Sillence, “Efficient Radar Cross Section Calculations on Airframe Geometries at High Frequencies,” American Institute of Aeronautics and, Astronautics, AIAA Test and Evaluation International, Aerospace Forum, pp. 146-155, 1996.[6] G. T. Ruck, D. E. Barrick, W. D. Stuart and C. K. Krichbaum, Radar Cross Section Handbook, Volume1, Volume2, New York: Plenum Press, 1970.[7] J. Boersma, “Computation of Fresnel Integrals,” Math. Comp., vol.14, pp.380, 1960.
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