Abstract

The Extremely Large Telescope (ELT) is a 40m-class optical and infrared telescope being built in Chile. The ELT has a complex geometry, with a rotating structure and a dome that must be protected from wind effects to ensure accurate observations. To study the wind flow within the dome, a computational fluid dynamics (CFD) model was created. The model used a porous media approach to represent the windscreen, a crucial component that shields the telescope from wind. The CFD model was validated against wind tunnel test data and showed good agreement. The model was then used to study the performance of the windscreen in various load cases, including different angles of attack and elevation configurations.

The results showed that the windscreen is effective in shielding the telescope from wind, with velocities near the mirrors remaining relatively low. The study also demonstrated the importance of using porous media to represent complex structures, such as the lattice truss structures within the dome. The porous media approach allowed for a significant reduction in computational resources while maintaining accuracy.

The CFD model will be used in future studies to analyse convective heat exchanges within the dome and to assess the thermal deflections of the main structure during observational periods. Overall, the study demonstrates the effectiveness of CFD modelling in understanding the complex wind flow within the ELT dome and in optimizing the design of the windscreen and other components.