Turbulence Statistics and Shock Attenuation by Traveling Waves in Compressible Turbulent Channel Flow

Surface traveling waves are known to reduce separation and turbulence in incompressible flows, but their effect in compressible regimes remains largely unexplored. Large eddy simulations are performed using a curvilinear immersed boundary LES method to study turbulent channel flow over traveling-wave walls at Mach numbers M=0.5 & M=1.5. Stationary wavy walls exhibit persistent separation and, in the supersonic case, strong shock patterns. Introducing traveling waves removes separation in both regimes and increases near-wall streamwise momentum. In the supersonic case, waves traveling with the flow weaken shocks, while upstream-traveling waves intensify them. Based on flow reattachment behavior, it is hypothesized that turbulence intensities are elevated near the wall in traveling wave cases but decay more rapidly away from the surface, while stationary walls may sustain turbulence farther from the wall. These results suggest that traveling waves may serve as a promising passive control strategy for separation and shock mitigation in high-speed flows.