Spatio-temporal characteristics of secondary instabilities in swept wing boundary layers

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Stationary waves approximately aligned with the flow direction develop in the laminar boundary layer of swept wings in low freestream turbulence conditions. These, so-called Crossflow vortices, undergo spatial amplification and amplitude saturation and deeply modify the boundary layer causing the destabilization of secondary high frequency instabilities. The rigorous amplification of these secondary modes has been identified as the cause of turbulent breakdown by recent investigations encompassing experimental, numerical and theoretical studies. In this paper experiments are conducted towards the identification and measurement of secondary crossflow instabilities. Detailed hotwire experiments are performed on a swept wing model at the location of primary instability saturation. In order to deterministically capture the spatio-temporal evolution of the secondary structures, measurements were phase conditioned using concurrent forcing of relevant frequencies by means of a DBD plasma actuator mounted upstream of the measured domain. The actuator effect was to enhance the amplitude of the forced modes. Additionally, the deterministic locking of the instability phase to the phase of the actuation allowed phase averaged reconstruction of the spatio-temporal evolution of these structures.

Original languageEnglish
Title of host publication46th AIAA Fluid Dynamics Conference
PublisherAmerican Institute of Aeronautics and Astronautics Inc. (AIAA)
Number of pages14
ISBN (Print)9781624104367
Publication statusPublished - 2016
Event46th AIAA Fluid Dynamics Conference, 2016 - Washington, United States
Duration: 13 Jun 201617 Jun 2016
Conference number: 46


Conference46th AIAA Fluid Dynamics Conference, 2016
CountryUnited States
Internet address

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