Instability of Unidirectional Flows for the 2D Navier–Stokes Equations and Related $$\alpha $$-Models

Stability criteria for the 2D α-Euler equations

“…This topic is quite classical and well-studied, and we refer to [3,4,13,14,15,16,36]. The setup as in (1.18) was also used in many papers [9,11,12,30,33,42], but the closest to the current work is [9]. We mention also [32] regarding connections to the Birman-Schwinger operators.…”