Seminar: Linear Stability and Receptivity in Shockwave / Boundary-layer Interaction

Abstract:

Shock wave / boundary layer interactions arising on aeronautical vehicles are prone to unsteadiness with a low frequency two orders of magnitude less than turbulence which can induce severe aerodynamic loads. This seminar aims to take a review of current knowledge in the field and give some ideas for future developments. The unsteady dynamics of an oblique shock wave / boundary layer interaction (SWTBLI) on a flat plate is investigated. A numerical tool based on CFD software where the stability and receptivity analyses are developed inside the code for the supersonic regime. Laminar and turbulent SWBLI simulations, linear stability analyzes are conducted for many configurations in Reynolds and Mach numbers. The results suggest, for transitional SWBLI, that the low-frequency dynamics is not related to a global mode of the flow for two-dimensional perturbations but under certain conditions the flow can develop a non-oscillating three-dimensional instability. Further analysis shows that the flow is essentially a selective noise amplifier and developing convective type instabilities. An analysis of receptivity shows that the flow is selective around a Strouhal number St = f.d*/Uoo ~ O(0.1) and characterized by shear instabilities. At low frequency, the disturbance is more and more localized in the shock and the selectivity is of the low-pass type. This result is valid whether the perturbation is 2-D or 3-D.

About Speaker:

Dr. Jean-Christophe Robinet received his PhD from University of Toulouse / ISAE in 1999 on the subject of shock wave stability.  He then performed post-doctoral research until 2001 at the University of Marseille (IUSTI), with J.-P. Dussauge on the stability and the receptivity of the compressible peeled flows.   Since then, he has been a professor at Arts et Métiers, in Paris, rising to the rank of Professor in 2011.  Since 2019, he has been the head of the Dynfluid Laboratory.  His main interests include stability analysis and transition for complex flows, separated flows,  flow around roughness and Shockwave / boundary layer interactions.