Linear stability theory and bypass transition in shear flows

This paper gives a brief introduction and review of linear stability theory with emphasis on nonmodal effects. The temporal and spatial framework is d iscussed and the response to periodic and stochastic forcing is addressed. An extension to nonautonomous evolution problems is presented. Bypass trans ition due to the secondary instability of streaks is used as an example to illustrate the role of a nonmodal linear mechanism in the breakdown to turb ulence. (C) 2000 American Institute of Physics. [S1070-664X(00)97105-2].