Physics-Informed Acoustic Liner Optimization: Balancing Drag and Noise

Pore-resolved direct numerical simulations (DNS) of turbulent flows grazing over acoustic liners with aerodynamically and/or acoustically optimized orifice configurations are presented. The DNS explore a large parameter space, studying various families of orifice geometries, including the influence of orifice shape, orientation, and the number of orifices. All flow cases show an increase in drag compared to the smooth wall. However, the added drag can be reduced by as much as approximately 55% as compared to conventional acoustic liners by simply altering the shape of the orifice or its orientation, in the case of a noncircular orifice. Complementary acoustic simulations demonstrate that this reduced drag may be achieved while maintaining the same noise reduction properties over a wide range of frequencies.