“…where for (x, y) ∈ T × R and T = R/Z, u is the velocity vector, ̺ is the density, P is the pressure, ϑ is the temperature, γ is the ratio of specific heats, and M is the Mach number of the reference state. The question of stability of Couette flows has a long history, see [1], [2], [6], [7], [8], [11], [12], [13], [15] for the compressible fluids and see [3], [4], [5], [9], [10], [14], [16] for the incompressible fluids. The Couette flow,…”