Streaks in high-speed boundary layers: Assessment via the full nonlinear boundary-region equations

Adrian Sescu, Mohammed Afsar, Yuji Hattori

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Streamwise vortices and the associated streaks evolve in boundary layers over flat or concave surfaces as a result of various disturbances initiated in the upstream or from the wall surface. Following the transient growth phase, the fully-developed vortex structures become susceptible to inviscid secondary instabilities resulting in early transition to turbulence via bursting processes. In the incompressible regime, a vast body of work has been devoted to understand the initiation and development of these streaks, as well as the conditions under which they undergo secondary instabilities. For high-speed boundary layers, on the other hand, additional complications due to the compressibility and thermal effects arise, the level of contribution of which scales with the Mach number. In this paper, we study streaks in high-speed boundary layers via the numerical solution to the full nonlinear boundary region equations, which is the high Reynolds number asymptotic form of the Navier-Stokes equations, under the assumption that the streamwise wavenumber of the disturbances is much smaller than the wavenumbers associated with the crossflow directions, commensurate with long streamwise wavelength of the primary vortex disturbance. The effect of the spanwise separation of the vortices and the Mach number, which is varied between high-subsonic (M = 0.8) to low-hypersonic (M = 6) regimes, is quantified and discussed.

Original languageEnglish
Title of host publicationAIAA Scitech 2020 Forum
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624105951
Publication statusPublished - 2020
EventAIAA Scitech Forum, 2020 - Orlando, United States
Duration: 2020 Jan 62020 Jan 10

Publication series

NameAIAA Scitech 2020 Forum
Volume1 PartF


ConferenceAIAA Scitech Forum, 2020
Country/TerritoryUnited States


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