EXPERIMENTAL STUDIES OF THE LOCALIZED DISTURBANCES AND THEIR SECONDARY HIGH-FREQUENCY INSTABILITY IN THE FLAT PLATE, UNSWEPT AND SWEPT WING BOUNDARY LAYER (REVIEW)

Read more Results of experimental studies of the streaky structures instability at nonlinear stage of this process in the shear flows are shown in this work. Flow patterns of the streaky structures with secondary high-frequency disturbances generated on them during its spatial evolution are discussed. Different scenarios of the coherent vortical structures occurrence and downstream evolution in the flat plate, unswept and swept wing boundary layer are considered. Features of the sinusoidal and varicose instability of the longitudinal stationary streaky structure at nonlinear stage of its downstream development are shown. To these features concern: modulation of streaky structure in transverse and streamwise direction by frequency of secondary disturbances, occurrence of new streaky structures downstream and occurrence and development of the nonstationary localized vortices such as Λ-structures in both cases. Development of a nonlinear stage of flow instability is considered both in the region of the adverse and zero pressure gradient

Keywords:
nonlinear flow instability, streaky structures, secondary instability, flat plate, unswept and swept wing, Λ-structures.
УДК 532.526.3

EXPERIMENTAL STUDIES OF THE LOCALIZED DISTURBANCES AND THEIR SECONDARY HIGH-FREQUENCY INSTABILITY IN THE FLAT PLATE, UNSWEPT AND SWEPT WING BOUNDARY LAYER (REVIEW)