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On the convectively unstable nature of optimal streaks in boundary layers. (English) Zbl 1055.76019
The main results of the present paper may be summarized as follows: the instability of saturated optimal streaks in the flat-plate boundary layer is clearly convective. It is even more convective than in the Blasius boundary layer in the absence of streaks. The instability of optimal streaks is found to be unambiguously convective for all streak amplitudes and streamwise stations. Note that the investigations in this paper are motivated by the need to understand the physics of bypass transition in boundary layers with high levels of free-stream turbulence.

76E15 Absolute and convective instability and stability in hydrodynamic stability
76D10 Boundary-layer theory, separation and reattachment, higher-order effects
76F06 Transition to turbulence
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