Smart Acoustic Lining for UHBR Technologies Engine: from the design of an electroacoustic metasurface to experimental characterization under flow

The SALUTE project aims at evaluating performance of electroacoustic metasurface, employing a surface array of controlled electroacoustic actuators, for smart acoustic lining under grazing turbulent flow to be used in UHBR Technologies Engines. Theoretical and numerical investigations have been carried out for designing innovative concepts for complex aero-acoustic characterization in an engine mock-up. A specific focus was placed in the realization of prototypes for evaluating the metacomposite liner performances in 3D liners close to real engine implementation, its process complexity and robustness. This project provides new tools for designing smart acoustic liners; while acoustical experimental tests demonstrate efficiency and robustness of such technology for controlling UHBR noise emission. This paper presents the concept development from theory to technological realization and characterization by produced numerical tools. The experimental results obtained with the liners in acoustic flow duct facilities (FDF) have been realized in the PHARE facilities of Ecole Centrale de Lyon. Different configurations of liners have been tested using similar flow conditions as in target engine: 1 passive liner used as reference and a 3D active liner based on an array of electroacoustic absorbers. The final tests campaign comprises acoustics and aerodynamics measurements to characterize the aeroacoustics flow conditions, the membrane behavior, the achieved synthetic acoustic impedance and the resulting insertion loss.