Introduction

The focus of the present book is instability phenomena in subsonic jets which are of much interest both from fundamental and practical viewpoints. Mean velocity profiles of the jet shear layers are inflectional ones resulting in the Kelvin–Helmholtz vortices. The initial stage of their evolution is well predicted by the linear stability theory. The following nonlinear events at the laminar jet breakdown are characterized by saturation of the vortices and their amalgamation.