Transonic Buffet Characteristics Under Conditions of Free and Forced Transition

Transonic buffet is commonly associated with self-sustained flow unsteadiness involving shock-wave/boundary-layer interaction over airfoils and wings. The phenomenon has been classified as either laminar or turbulent based on the state of boundary layer immediately upstream shock foot, distinct mechanisms for two types have suggested. case known to be a global linear instability. Herein, large-eddy simulations are used first time make direct comparisons by examining free- forced-transition conditions. Corresponding Reynolds-averaged Navier–Stokes equations also performed comparison scale-resolving approach linking findings existing literature. Coherent features scrutinized using both data-based spectral proper orthogonal decomposition time-marched results operator-based stability resolvent analyses within framework. It demonstrated that essential dynamic remain same (and levels aerodynamic modeling hierarchy), suggesting arise due fundamental mechanism.