Adaptive Drainage Slots for Acoustic Noise Attenuation

Cornerstone Research Group, Inc. (CRG) demonstrated feasibility in the reduction of noise attributed to drainage slots in jet engine acoustic liners. This was accomplished through the development of design rules for optimum slot design and concept development of the implementation of adaptive material technologies to control slot dimensions. CRG brought thistechnology to a technology readiness level (TRL) 2 after the Phase 1 effort and will bring a TRL 4 after the Phase 2 effort. The Phase 1 effort provided simulated data for the acoustic designer to start to understand and develop preliminary models on the effects of drainage slots to the liner's acoustic impedance characteristics. This data has provided justification to pursue adaptive solutions that will counteract the adverse effects of drainage slots through adaptive means. In Phase 2, CRG will refine the design, scale up fabrication, demonstrate a full-scale operationally relevant aircraft part, and analyze manufacturing costs as part of a comprehensive Technology Insertion Plan.