Abstract: | The results of experimentally investigating the initial stage of development of shear instability of the interface between two immiscible fluids relatively oscillating during the parametric excitation of standing internal waves are presented. Three stages of distortion of the sinusoidal wave profile are distinguished: the formation of short secondary waves, their breaking, and transition to large-scale vortex formations. It is shown that in the nodal zones of a standing wave quasi-stationary wave perturbations start to develop at wave steepnesses Γ ~ 0.08–0.13 and critical Reynolds numbers of the laminar boundary layer R ~ 90–300. The experimental data are compared with the classical Kelvin-Helmholtz theory. |