The Origin and Scaling of Low-Frequency Unsteadiness in Shock-Separated Boundary layers using DNS, LES and Input/Output Analyses
Abstract
The dynamics of shock-boundary layer interactions are important as the shockwave often exhibits strong, low-frequency motion. This motion can lead to large, unsteady loading and increased heat transfer that can be detrimental to flight vehicles. The study of mechanisms behind this unsteadiness has garnered great interest, with evidence obtained for both upstream and downstream influences potentially dependent on some measure ofinteraction strength and Reynolds number. The physical mechanism involved in the low-frequency unsteadiness of shockwave and turbulent boundary layers (STBLI) has been a point for debate for several decades.Recent work has shown evidence that the low-frequency unsteadiness STBLIs is in fact driven by the dynamics of certain inviscid vortical structures (IVS) that are aligned with the streamwise direction and mix the inviscid high momentum fluid with the near wall separated flow. The origin of these large-scale inviscid vortical structures is yet unknown. They might originate from the elevated streamline curvature at the separation point and extend downstream with the vortex cores oriented in the streamwise direction.Alternatively, these large vortical structures might be a product of the three-dimensional structure of the separated flow. It is also possible that both streamline curvature and dynamics of the separated flow are at play, one being more or less dominant in the range of weak to strong interactions.The proposed work will provide explanations and supporting evidence via simulation data for: (A) The origin and receptivity of the IVS that are found in SBLIs for various interaction strengths, (B) the effect of Reynolds number on such structures, (C) the effect of IVS strength on the separation length, and (D) a robust separation scaling across the flow conditions.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 06, 2021
- Source ID
- N000142112305
Entities
People
- M. Pino Martı́n
Organizations
- Office of Naval Research
- United States Navy
- University of Maryland