The Formation of Secondary Structures and Random Perturbations in the Development of Periodic Lambda-Structures in a Laminar Boundary Layer
The evolution of periodic Λ-structures at the nonlinear stage of laminar-turbulent transition in a 2D boundary-layer has been investigated experimentally. Particular attention has been payed to the formation of secondary structures flanking the main disturbance structure and to the development of random perturbations within the periodically excited transition process. The nonlinear development of the time-harmonic instability waves excited by means of a slit source leads to a formation of the Klebanoff-regime (K-regime) of boundary-layer transition.
The main object of the present investigation is to improve the understanding of the nonlinear disturbance development, i.e. the process of formation of Λ-structures and their breakdown. Following the idea of the similarity between transitional and turbulent structures in boundary-layers this might lead to a better understanding of the mechanism responsible for the production of turbulence and its possible control.
KeywordsRandom Perturbation Fundamental Wave Transitional Flow Nonlinear Stage Disturbance Source
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