In this presentation, we will examine how the wake generated by micro-vortex generators or the presence of an upstream sweep affects the physics of a canonical Shock–Boundary Layer Interactions (SBLI) using high-fidelity numerical simulations and advanced post-processing techniques to better understand the underlying flow dynamics.

We will then explore how, in many compressible flows, different types of waves—aerodynamic, acoustic, and entropic—interact and couple, sometimes generating strong oscillations and pronounced tonal noise at specific frequencies. These waves have distinct characteristic velocities and typically interact at flow singularities, such as walls, corners, or shocks.
Several configurations will be discussed, including non-ideally expanded jets issuing from pipe nozzles and TIC nozzles, as well as supersonic air intakes. All of these systems exhibit significant flow oscillations driven by wave coupling.

Finally, we will look at the low-Mach-number regime (M < 0.1), where most feedback mechanisms disappear. Interestingly, the aeroacoustic feedback loop responsible for airfoil tonal noise remains active.

Why does this mechanism persist when others vanish?