Stabilization of hypersonic shockwave/boundary-layer interactions with phononic metamaterials

Hypersonic flight can revolutionize commercial transport, defense, and space exploration. However, hypersonic vehicles face severe flow disturbances that can degrade their structural integrity by generating high temperatures and acoustic loads. In this work, we investigate phononic metamaterials (PMs) as a novel approach for stabilizing these disturbances. PMs are engineered materials that exhibit frequency ranges, known as band gaps, where wave propagation is significantly inhibited. Our findings show that these band gaps effectively mitigate unsteadiness in hypersonic shockwave/boundary-layer interactions (SWBLIs). Specifically, we analyze a bilayer PM subsurface exposed to a Mach 7.2 cylinder-induced SWBLI, comparing its performance to a rigid wall control. Spectral analysis reveals that the PM selectively attenuates disturbances and significantly stabilizes flow structures away from the fluid-PM interface. These results highlight PMs as a transformative technology for enhancing hypersonic vehicle resilience and enabling reusable hypersonic systems, paving the way for safer, more efficient hypersonic flight.