On the impact of the orifice geometrical features on the performance of an acoustic liner

Abstract

This computational study investigates the impact of manufacturing inaccuracies of face sheet orifice geometries on acoustic liners’ impedance and flow dynamics. Normal Impedance Tube (NIT) lattice-Boltzmann very-large eddy simulations at 130 and 145 dB and 800, 1400, and 2000 Hz reveal that sharp-edged geometries present increased acoustic resistance and absorption than geometries with smoother edges. Rounded and double-chamfered edge shapes, mimicking real-world imperfections, reduce the resistance component of impedance by up to 28%, thus reducing the absorption coefficient. The inspection of the velocity field shows the flow features that cause these differences. Results demonstrate that minor edge imperfections, potentially due to manufacturing, may alter liner performance. This underscores the need to account for geometric imperfections in industrial design and quality control.