基于数值模拟的大口径高精度射电望远镜台址风障优化设计研究

随着射电望远镜口径增大、观测频率提高, 对其指向精度的要求也越来越高. 然而, 望远镜服役于野外台站, 台址风扰对天线指向精度的影响在高频段观测时已不能忽略. 由于风扰的时变性, 现有的抗风方法无法保障大口径高指向精度望远镜在高频段的有效观测时长. 因此, 提出了一种基于风障精确布置改善台址风环境的方法. 通过数值模拟构建了风障仿真模型, 并将仿真结果与风洞实测数据比较, 两种孔隙率风障的平均误差分别为3.7%和6.1%, 保证了风障模型的可靠性. 以新疆奇台射电望远镜(QiTai radio Telescope, QTT)台址为例, 基于QTT台址斜坡地形构建了计算域模型, 开展单风障不同高度、不同孔隙率的系列风场仿真试验, 得到了风障参量与下游挡风效果的关系. 基于单风障合理高度和最优孔隙率设置南北风障, 仿真结果表明在确定高度下最优孔隙率可以组合, 孔隙率0.1-0.1组合的风障挡风效果最优, 南方向来风在天线区域可以有效降低75%以上的风速.

Optimal Design of the Wind Barrier for Large-aperture and High-precision Radio Telescope Site Based on Numerical Simulation

With the increase in aperture and observation frequency of radio telescopes, there is a growing demand for enhanced pointing accuracy. However, telescope is operated at the field station, and the influence of wind disturbances on telescope pointing accuracy cannot be ignored in high frequency observation. Due to the time-varying characteristics of wind disturbances, the existing wind resistance methods cannot guarantee the effective observation time of large aperture and high pointing accuracy telescope in high frequency. Therefore, a method to improve the wind environment of the site based on the precise arrangement of wind barriers is proposed. The wind barrier simulation model is built, and the average error of the two porosity wind barriers is 3.7% and 6.1% respectively by comparing the simulation results with the measured data of the wind tunnel, which ensures the reliability of the wind barrier model. The QiTai radio Telescope (QTT) site in Xinjiang is taken as an example. The computational domain model is developed based on the slope terrain of the QTT site, and a series of wind field simulation tests are conducted to investigate the impact of different heights and porosities of a single wind barrier on downstream wind protection effectiveness. The parameters for simulating the north-south wind barrier are determined based on an appropriate height and optimal porosity. The results indicate that combining the determined height with a porosity of 0.1-0.1 yields the most effective wind reduction in the antenna area, with south winds experiencing a decrease in speed by over 75%.