Analysis of SPL Reduction Possibilities Inside the WFI ATHENA Filterwheel Assembly

Ariane 5 rocket produces very high sound pressure levels during launch, what can influence structures located inside the fairing. In Wide Field Imager (WFI) project, the main part of the filterwheel assembly (FWA) is an extremely thin ( 240 nm) filter of large area (170 × 170 mm), very sensitive to noise and vibrations. The aim of this study was to minimize the sound pressure affecting filter surface. Several modifications of the filterwheel assembly including e.g. different filterwheel angular position or height were analysed using finite element method (FEM) simulations. The possible modification options were greatly limited by nonacoustical design factors. The results from computer simulations were compared with measurements of the prototype FWA. The results will be used in further design process of WFI filterwheel assembly.