A first test with pressure measurements on the primary mirror was performed at the LASEN boundary layer tunnel as part of the program for wind loading on the VLT telescope in a retractable enclosure (cf. section 4.1.4). The 1/80 model of the telescope was surrounded by a low platform as it was at the time alternatively envisaged for an open air arrangement of the VLT (fig.).
Figure: Distribution of pressure taps and sectors on the 1/80 models of the primary mirror
Because of its sharp edges the mirror model was considered to be Reynolds independent. Two types of measurements were done: