Local Stability Theory of High-Speed Boundary Layers over Compliant Panels

Boundary layer stability mechanisms have been extensively studied for various flow configurations in order to predict transition to turbulence. The underlying assumptions of a rigid structural domain, however, restrict the application of numerical results away from more realistic flight conditions. In order to capture the potential influence of structural compliance in the presence of a grazing flow, we analyze the canonical problem of a flat plate laminar boundary layer over a mechanically compliant wall. Local linear stability theory - both in temporal and spatial framework - in combination with the thin plate theory suggests a distinct region of fluid-structural coupling in the non-dimensional structural parameter plane. Non-dimensional fluid parameters, namely Reynolds, Mach number, and perturbation frequency, have only a minor impact on the boundary of this region, which allows for quantification of the impact boundaries to predict fluid-structure interaction of a given system.