Radome-enclosed antennaʹs temperature and velocity fields

Thermal distortion is a critical design consideration for the Haystack Ultrawide-band Satellite Imaging Radar (HUSIR) with respect to its performance at W-band. This design consideration is needed due to the thermal distortion effects on the surface accuracy of a parabolic reflector. For example, a tight surface tolerance of ∼100 microns root-mean-squared is required to obtain 85 percent antenna performance efficiency for the 37 m (120 foot) diameter reflector. An understanding of the temperature and velocity fields aids compensation of these losses. Computational fluid dynamics models (CFD) are too computationally expensive to implement in a control algorithm. This work develops a simplified analytical model to predict the surface temperature of a metal antenna based on external diurnal temperature variations. This work also applies proper orthogonal decomposition (POD) to simulated CFD data and creates a reduced order model of the fluid system that characterizes the dominant features of both the temperature and velocity fields.