Optics and Precision Engineering, Volume. 30, Issue 4, 442(2022)
Wind disturbance simulation and optical performance prediction for large ground-based optical telescopes based on two-dimensional stochastic fields
As the aperture of large ground-based optical telescopes increases, wind disturbance has become one of the most significant dynamic factors degrading the performance of telescopes. To investigate the influence and interaction principles of wind disturbance on the performance of telescopes, a time-history simulation of the wind disturbance response and performance prediction for telescopes were performed in the time domain. First, the structural parts of the telescope were simply introduced, and a dynamic model of the telescope was established using the finite element method. Using modal transformation, the dynamic model, expressed in nodal coordinates, was transformed into modal coordinates, thus greatly decreasing the model dimension and greatly improving the computational efficiency. Second, a time-history simulation method for wind speed was presented based on two-dimensional stochastic fields. The wind speed field in the doom was expressed as a two-dimensional stochastic field that varied according to the temporal and spatial frequencies. The numerical instability occurring in the Cholesky decomposition of the cross-power spectrum matrix in the spectral method was avoided by introducing the wave-number spectrum. The simulation efficiency was further improved by applying the fast Fourier transform (FFT) technique. Finally, using a ground-based telescope with a 2 m aperture as a case study, a time-history simulation of the wind speed, wind disturbance response, and system performance prediction for the telescope was performed. The simulation results showed that wind disturbances with a mean speed of 10 and 15 m/s would result in a maximum surface root mean square error of the primary mirror of approximately 45 and 70 nm, respectively. In addition, the wind disturbance acting on the secondary mirror and truss would mainly cause optical axis angle and position errors.
Get Citation
Copy Citation Text
Yuyan CAO, Jianli WANG, Zhichen WANG, Hongwen Li, Yan ZHANG, Hongliang CHU, Yuxia LI. Wind disturbance simulation and optical performance prediction for large ground-based optical telescopes based on two-dimensional stochastic fields[J]. Optics and Precision Engineering, 2022, 30(4): 442
Category: Micro/Nano Technology and Fine Mechanics
Received: Jun. 22, 2021
Accepted: --
Published Online: Mar. 4, 2022
The Author Email: CAO Yuyan (yuyan_cao@126.com)