Numerical analysis of wind load on ground-based telescope

Pan Nian; Ma Wenli; Huang Jinlong

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.

1. Institute of Optics and Electronics,Chinese Academy of Sciences,Chengdu 610209,China;

2. University of Chinese Academy of Sciences,Beijing 100049,China

Received Date: 2014-05-05

Rev Recd Date: 2014-06-15

Publish Date: 2015-01-25

Key words:

telescope /
wind load /
CFD /
surface accuracy

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.

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Reference (29)

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Numerical analysis of wind load on ground-based telescope

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