Dynamic Passive Control of Turbulent Drag via Subsurface Resonant Phononic Material

This work presents a passive turbulence-control strategy based on a resonant phononic material (RPM) embedded beneath the surface of a turbulent channel flow. The RPM is modeled as a mass–spring–damper chain tuned to a defect-induced resonance that interacts with near-wall turbulence. Using a weakly coupled fluid–metamaterial framework, we show that both the wall-pressure forcing and the RPM response collapse onto a narrow frequency band dictated by the designed resonance, and that within a moderate actuation-amplitude range the system produces measurable transient drag-reduction effects. Direct numerical simulations (DNS) further reveal a well-defined stable interval of RPM damping coefficients, with a sharp transition between underdamped (growing) and overdamped (bounded) response regimes. To enable rapid exploration of RPM configurations, we also develop a reduced-order weakly coupled model in which a linear wall-pressure approximation replaces the full pressure-Poisson solution; this simplified model accurately reproduces the key bifurcation behavior observed in DNS. Overall, the study clarifies the mechanisms governing RPM–flow coupling and informs the design of passive, energy-efficient compliant surfaces for aerodynamic applications.