基于NURBS和梯度法的飞艇形状优化
Airship shape optimization with NURBS and gradient based algorithms
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摘要: 采用非一致有理样条曲线(NURBS)作为飞艇外形参数化方法、基于梯度的优化方法、飞艇体积作为约束条件、飞艇的阻力系数作为目标函数的优化流程对平流层流动条件下的飞艇外形进行了优化.阻力系数通过求解二维黏性不可压缩流场获得,阻力不但包含了形状阻力也包括了黏性阻力.优化过程以LOTTE飞艇的形状为初始形状,优化的结果表明优化后飞艇的气动性能明显改善,阻力系数有了比较明显的降低.优化的结果也同时证明了该方法适用于飞艇的优化命题.
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关键词:
- 平流层飞艇 /
- 优化 /
- 非一致有理样条曲线(NURBS) /
- 梯度法 /
- computational fluid dynamics模拟
Abstract: The present work attempts to conduct shape optimization of stratospheric airships with a method based on a combination of NURBS (non-uniform rational B-spline) and a gradient-based optimization algorithm.Drag coefficient was chosen as the objective function and airship volume as the constraint.NURBS based geometric parameterization was used because of its more efficient representation of the discrete geometric data than other methods (e .g. B?zier curve).Drag coefficient was obtained during the optimization iteration by solving two dimensional incompressible viscous flow field.Both form and viscous drags were considered when drag coefficient was calculated.Using LOTTE airship shape as initial shape,an improved shape with the above algorithm was obtained.Airship with the new shape obviously had better aerodynamic performance.It is eventually proved that the optimization method above can be effectively applied to airship optimization. -
[1] Khoury G A,Gillett J D.Airship technology[M].Cambridge:Cambridge University Press,1999. [2] Funk P,Lutz T,Wagner S.Experimental investigations on hull-fin interferences of the LOTTE airship[J].Aerospace Science and Technology,2003,7(8):603-610. [3] 张丹,郭雪岩.平流层双轴椭球体飞艇绕流场的数值分析 [J].力学季刊,2008,29(4):556-564. ZHANG Dan,GUO Xueyan.Numerical analyses on ambient flow of a double-axis ellipsoidal stratospheric airship[J].Chinese Quarterly of Mechanics,2008,29(4):556-564.(in Chinese) [4] 林瑞坤,郭雪岩.带螺旋桨平流层飞艇气动性能的数值模拟 [J].力学季刊,2010,31(3):355-362. LIN Ruikun,GUO Xueyan.Numerical analysis of aerodynamic performance for stratospheric airship with a propeller[J].Chinese Quarterly of Mechanics,2010,31(3):355-362.(in Chinese) [5] Emre A,Lyle N L.Separated turbulent flow simulations using a reynolds stress model and unstructured meshes[R].AIAA Paper 2005-1094,2005. [6] 刘建闽,薛雷平,鲁传敬.平流层飞艇绕流场与柔性变形的数值模拟[J].力学季刊,2006,27(3):440-448. LIU Jianmin,XUE Leiping,LU Chuanjing.Coupling computation of ambient flow and deformation of elastic membrane body[J].Chinese Quarterly of Mechanics,2006,27(3):440-448.(in Chinese) [7] Lutz T,Wagner S.Numerical shape optimization of natural laminar flow bodies[R].AIAA Paper 98-31525,1998. [8] Lépine J,Guibault F,Trepaniér J Y.Optimized nonuniform rational B-spline geometrical representation for aerodynamics design of wings[J].AIAA Journal,2001,39(11):2033-2041. [9] Driver J,Zingg D W.Optimized natural-laminar-flow airfoils[R].AIAA Paper 2006-247,2006. [10] Painchaud-Ouellet S,Tribes C,Trépanier J Y,et.al Airfoil shape optimization using a nonuniform rational B-splines parameterization under thickness constraint[J].AIAA Journal,2001,40(10):2170-2178. [11] 琚亚平,张楚华.基于人工神经网络与遗传算法的风力机翼优化设计方法[J].中国电机工程学报,2009,29(20):106-111. JU Yaping,ZHANG Chuhua.Optimal design method for wind turbine airfoil based on artificial neural network model and genetic algorithm[J].Proceedings of the CSEE,2009,29(20):106-111.(in Chinese) [12] 王锐,祁大同,王学军.离心压缩机弯道回流器子午型线的改进研究[J].中国电机工程学报,2010,30(2):109-114. WANG Rui,QI Datong,WANG Xuejun.Improvement of meridian plane profile for return channel of a centrifugal compressor[J].Proceedings of the CSEE,2010,30(2):109-114.(in Chinese) [13] 吴子牛,王兵,周睿,等.空气动力学(下册)[M].北京:清华大学出版社,2007. [14] Rogers D F.An introduction to nurbs with historical perspective[M]. London: Academic Press,2001. [15] Spellucci P.DONLP2 short user guide[R].Darmstadt:Technical University at Darmstadt,1999. [16] Nocedal J,Wright S J.Numerical optimization[M].NewYork:Springer,1999.
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