Asymptotic theory of perturbations inducing a pressure gradient in a transonic flat-plate boundary layer

The role of asymptotic approaches to the study of viscous-inviscid interaction mechanisms in transonic outer flows is discussed. It is noted that there are several versions of multideck asymptotic constructions describing the self-induced pressure effect in transonic boundary layers. The asymptotic theory is used to uncover the internal structure of fluctuation fields, to treat instability-generating processes, and to analyze the behavioral features of linear and nonlinear wave fluctuations. Additionally, the properties of the eigenspectrum are described.