A first principles study of convection cells to shear flow instability in 2D Yukawa liquids driven by Reynolds stress.

The stability of kinetic-level convection cells (wherein the magnitude of macroscopic and microscopic velocities are of same order) is studied in a two-dimensional Yukawa liquid under the effect of microscopic velocity perturbations. Our numerical experiments demonstrate that for a given system aspect ratio β viz., the ratio of system length [Formula: see text] to its height [Formula: see text] and number of convective rolls initiated [Formula: see text], the fate of the convective cells is decided by [Formula: see text]. For [Formula: see text], Reynolds stress is found to be self-consistently generated and sustained, which results in tilting of convection cells, eventually leading to shear flow generation, whereas for [Formula: see text], parallel shear flow is found to be untenable. An unambiguous quantitative connection between Reynolds stress and the onset of shear flow using particle-level data is established without free parameters. The growth rate of the instability, the role of frictional forces, generalization of our findings and the possibility of realizing the same in experiments are also discussed.