The Wind Field Analysis And Simulation Regulation Of Large Radio Telescope Site

With the development of human history and the progress of science and technology,the development of radio telescope observation technology has greatly promoted the development of astronomy and become one of the main driving forces for its development.The reflecting surface area of the telescope structure is one of the important performance indexes of the radio telescope.The large-diameter radio telescope can observe more and farther objects.At present,the largest aperture fully steerable radio telescope in the world is the green shore radio telescope(GBT,aperture 100 × 110m)built in 2000 in the United States.At present,China's largest aperture full steerable radio telescope is the 65 m aperture radio telescope of Shanghai Observatory,and it is planned to build the 110 m aperture full steerable radio telescope(QTT)in Qi Tai,Xinjiang.QTT has a large reflecting surface area,a large amount of its own weight,and a variety of actual working conditions and must meet high accuracy requirements to achieve good observation performance.However,the role of wind load in the natural environment will cause changes in the shape of the reflecting surface of the telescope,reduce the fitting accuracy of the shape of the reflecting surface,cause deflection and pointing errors,and reduce telescope's errors Its sensitivity and resolution seriously affect its performance.Therefore,it is necessary and urgent to reduce the influence of wind disturbance on the antenna.The main works are as follows:(1)In view of the problem that the working performance of large radio telescopes is affected by environmental factors,this thesis summarizes the main factors that affect the environment of large radio telescopes.From the point of view of the anti-wind disturbance design of large radio telescopes,summarizes the research methods and current research status of large radio telescopes affected by wind disturbance so far.And then combs them from the point of view of atmospheric boundary layer wind environment research.The main research methods of wind environment in atmospheric boundary layer are summarized,and the current research status of wind environment in different topographic landforms at home and abroad is summarized;(2)In the face of the high-precision design requirements for the 110 m aperture fully movable radio telescope QTT to be built in Qitai County,Xinjiang,this thesis analyzes the characteristics of the topography and the wind field distribution of the QTT site,a wind field distribution regulate technology of the QTT site with actively to reduce wind speed of the wind field in the area where the antenna is located is proposed,further,an equivalent wind field test for the miniature model of the wind field distribution regulate technology of the QTT site was built,by analyzing the test data,the range of low wind speed area in the model and the reduction of wind speed in the area by about 75% are given.The feasibility of the overall scheme of wind field analysis and simulation regulation is determined,and the technical basis for the subsequent application of computer numerical simulation in the wind field distribution regulation of the station site is provided;(3)In order to achieve more effective computer numerical simulation of the telescope site,using the technology of automatic generation of terrain surface,using GIS software to extract the point cloud coordinate file from the digital elevation model of the site,write and run Java program to convert it into command control file,and finally import gambit to generate the site terrain entity model and carry out the corresponding pre-processing operation,thus realizing qtt The transformation of station location from digital elevation model to terrain entity model results in qtt station location terrain entity model with high fitting degree,which solves the problem of complexity,low efficiency and low fitting degree caused by manual terrain entity model,and greatly improves the effectiveness of computer numerical simulation results;(4)According to the basic theory and method of computer numerical simulation,using the Fluent module built in ANSYS software,and the wind field distribution at the location of the telescope under different environmental wind speed,then combined with the wind field numerical calculation results of QTT site As well as the local natural geographical environment,the site wind field control measures are proposed,and the QTT site with the control measures are further simulated.It is found that the wind field distribution control measures can be used at the low altitude of the telescope A large low wind speed area is formed in the area,which reduces the wind speed in the low altitude area by 60% ? 20%,which proves the effectiveness of the overall scheme and control measures of wind field regulation,and shows that the application of this method in engineering practice will have significant application value.