Computational Fluid Dynamics Modeling of GMT

摘要

A detailed Computational Fluid Dynamics (CFD) model for the Giant Magellan Telescope (GMT) telescope has been developed and used to simulated and analyze the aero-optical environment around the observatory. The developed model accounts for the major observatory components such as the primary (M1) and secondary (M2) mirrors, the M2 supporting truss, other subcomponents of the telescope mount, and enclosure building along with the auxiliary and site support buildings on the summit. A large topographical area around the installation site is included. This study evaluates three different lower enclosure designs; a closed soffit, an open soffit and a perforated ring-wall (partially closed soffit). Time-varying CFD simulations provide detailed flow and temperature fields along the optical path, which are subsequently used to compute optical parameters such as Optical Path Difference (OPD) maps and Point Source Sensitivity normalized (PSSn), the GMT Image Quality (IQ) metric. Results show that enclosure-induced turbulent flow patterns and refractive index variations have a greater influence on optical performance compared to flow and thermal behavior external to the enclosure. Instantaneous and mean PSSn values obtained for the three soffit configurations show minor differences, indicating that the lower enclosure design has minimal impact on observatory optical performance for the simulated operating conditions.