Numerical analysis of wind load on ground-based telescope
-
摘要: 风载是影响地基望远镜性能的主要因素之一,为了研究风载荷的作用以及对望远镜性能的影响程度,首先建立了望远镜、圆顶和流场的几何模型。然后利用CFD(Computational Fluid Dynamics)分析了在外界风速为10 m/s 的情况下,3 种不同高角(30、60、120)流场中截面空气速度、压力、湍流动能以及主镜面的静压力的瞬态分布,最后通过有限元方法获得了主镜去除刚体位移后的面形。仿真结果表明,望远镜以不同高角观测时主镜面静压力功率谱密度与Gemini 望远镜的实测结果接近,真实模拟了风载荷的作用。由风载引起的镜面变形RMS 值分别为3.74E-1 nm,2.5E-2 nm,1.71E-1 nm,满足面形精度要求。Abstract: Wind load is one of the main factors that affects the performance of ground-based telescopes, in order to investigate the function of wind load and the influence degree on the telescope, firstly, the telescope, dome, and exterior flow field geometry were established. Secondly, Computational Fluid Dynamics (CFD) was used to analyze the instantaneous distribution of the air's velocity, pressure and static pressure on primary mirror, at three different altitude angular(30, 60, 120), when the wind at the speed of 10 m/s. Finally, the primary mirror surface accuracy was gotten after removed the rigid body displacement through the finite element method. The simulation results show that static pressure power spectral density of the primary mirror is close to the measured data of Gemini telescope, better simulate the practical effect of the wind load. The RMS values of the mirror surface deformation caused by wind load are 3.74E-1 nm, 2.5E-2 nm, 1.71E-1 nm meet the surface accuracy requirement.
-
Key words:
- telescope /
- wind load /
- CFD /
- surface accuracy
-
[1] Pierre Y B. The Design and Construction of Large Optical Telescopes[M]. New York: Springer, 2003. [2] [3] Neill D R, Sebag J, Warner M, et al. Wind induced image degradation of the LSST telescope [C]//SPIE, 2005, 5877: 1-11. [4] [5] [6] Ando H. Some airflow properties of telescope enclosures estimated from water-tunnel tests [J]. Publications of the Astronomical Society of the Pacific, 1991, 103: 597-605. [7] [8] Kiceniuk T, Potter K. Internal air flow patterns for the Keck 10 meter telescope observatory dome [R]. US: Keck Observatory Report #166, 1986. [9] [10] Quattri M, Koch F, Noethe L, et al. OWL wind loading characterization: a preliminary study [C]//SPIE, 2003, 4840: 459-470. [11] [12] Chylek T, Timothy C C, Shutt D J, et al. A numerical investigation of three dimensional turbulent air flow around WFCAM at the UK infrared telescope[C]//SPIE, 2004,5497: 161-173. [13] Quattri M R, Haase R M, Barreto C M, et al. Wind turbulence structure inside telescopes enclosures [C]//SPIE, 2008,7017: 1-13. [14] [15] [16] Young D S. Numerical simulations of airflow in telescope enclosures[J]. Astron J, 1996, 112: 2896-2908. [17] [18] Yang Dehua, Xu Lingzhe, Xu Xinqi. Wind disturbance study on large astronomical telescopes [J]. Optical Technique, 2009, 35(3): 342-346. (in Chinese) 杨德华, 徐灵哲, 徐欣圻. 大型光学天文望远镜风载作用分析[J]. 光学技术, 2009, 35(3): 342-346. [19] [20] Zhou Chao, Yang Hongbo, Wu Xiaoxia, et al. Influence of wind loading on the 1.2m telescope [J]. Infrared and Laser Engineering, 2011, 40(5): 889-893. (in Chinese) 周超, 杨洪波, 吴小霞, 等. 1.2 m 望远镜风载作用分析[J]. 红外与激光工程, 2011, 40(5): 889-893. [21] Cheng Jingquan. Principle and Design of Astronomical Telescope [M]. Beijing: China Science Technology Press, 2003. (in Chinese) 程景全. 天文望远镜原理和设计[M]. 北京: 中国科学技术出版社, 2003. [22] [23] [24] Xie Longhan, Zhao Xinyu, Zhang Jiongming. ANSYS CFX Fluid Analysis and Simulation [M]. Beijing: Electronic Industry Press, 2012. (in Chinese) 谢龙汉, 赵新宇, 张炯明. ANSYS CFX 流体分析及仿真[M]. 北京: 电子工业出版社, 2012. [25] Wang Fujun. Computational Fluid Dynamics Analysis-CFD Software Principles and Applications [M]. Beijing: Tsinghua University Press, 2004. (in Chinese) 王福军. 计算流体动力学分析-CFD 软件原理与应用[M]. 北京: 清华大学出版社, 2004. [26] [27] Cho M K, Warner M, Lee J P. Wind buffeting effects on the Gemini 8m primary mirrors[C]//SPIE, 2001, 4444: 302-314. [28] [29] Douglas G, Mac Mynowski, Konstantinos Vogiatzis. Wind loads on ground-based telescopes [J]. Applied Optics, 2006, 45(30): 7912-7923. -
点击查看大图
计量
- 文章访问数: 268
- HTML全文浏览量: 46
- PDF下载量: 253
- 被引次数: 0
下载:
