Transitional shock wave boundary layer interactions on a compression ramp at mach 4

James A.S. Threadgill, Jesse C Little, Stefan H. Wernz

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Strong laminar/transitional Shock Boundary Layer Interactions (SBLIs) have been investigated in the Mach 4 vacuum driven wind tunnel at the University of Arizona, with supporting CFD analysis. Such flows are extremely susceptible to large-scale separation which can limit control authority on high-speed vehicles. The research community has heavily focused on turbulent interactions, leaving little understanding on how laminar/transitional cases scale with varying external parameters. Four ramp angles of 15◦, 18◦, 22◦, and 28◦ have been tested on a flat plate (unit Reynolds number Re1 = 4.56 × 106 1/m) with a range of external length scales (Rex varies between 1.2 × 105 and 2.5 × 105 at the ramp corner). The low-Reynolds number test conditions provide an excellent opportunity for supporting DNS/LES studies. Separation length L/δ0 scales mildly with Reynolds numbers, increasing proportionally with Re1/4 δ0. Transitional reattachment behavior is found on strong SBLIs, located furthest downstream. Upon observation with high-speed schlieren, the separation shock demonstrates low-frequency unsteadiness at StL = 0.025, consistent with turbulent SBLIs. Further analysis of the data shows no upstream influence and that motion of the shear layer and reattachment shock precede motion of the separation shock foot. In addition, a slow moving density disturbance within the bubble is observed to propagate towards the shock foot and directly lead to shock motion. This configuration represents an excellent opportunity to study dynamic mechanisms within SBLIs, through elimination of upstream effects.

Original languageEnglish (US)
Title of host publicationAIAA Scitech 2019 Forum
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624105784
DOIs
StatePublished - Jan 1 2019
EventAIAA Scitech Forum, 2019 - San Diego, United States
Duration: Jan 7 2019Jan 11 2019

Publication series

NameAIAA Scitech 2019 Forum

Conference

ConferenceAIAA Scitech Forum, 2019
CountryUnited States
CitySan Diego
Period1/7/191/11/19

Fingerprint

Shock waves
Mach number
Boundary layers
Reynolds number
Wind tunnels
Computational fluid dynamics
Vacuum

ASJC Scopus subject areas

  • Aerospace Engineering

Cite this

Threadgill, J. A. S., Little, J. C., & Wernz, S. H. (2019). Transitional shock wave boundary layer interactions on a compression ramp at mach 4. In AIAA Scitech 2019 Forum (AIAA Scitech 2019 Forum). American Institute of Aeronautics and Astronautics Inc, AIAA. https://doi.org/10.2514/6.2019-0343

Transitional shock wave boundary layer interactions on a compression ramp at mach 4. / Threadgill, James A.S.; Little, Jesse C; Wernz, Stefan H.

AIAA Scitech 2019 Forum. American Institute of Aeronautics and Astronautics Inc, AIAA, 2019. (AIAA Scitech 2019 Forum).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Threadgill, JAS, Little, JC & Wernz, SH 2019, Transitional shock wave boundary layer interactions on a compression ramp at mach 4. in AIAA Scitech 2019 Forum. AIAA Scitech 2019 Forum, American Institute of Aeronautics and Astronautics Inc, AIAA, AIAA Scitech Forum, 2019, San Diego, United States, 1/7/19. https://doi.org/10.2514/6.2019-0343
Threadgill JAS, Little JC, Wernz SH. Transitional shock wave boundary layer interactions on a compression ramp at mach 4. In AIAA Scitech 2019 Forum. American Institute of Aeronautics and Astronautics Inc, AIAA. 2019. (AIAA Scitech 2019 Forum). https://doi.org/10.2514/6.2019-0343
Threadgill, James A.S. ; Little, Jesse C ; Wernz, Stefan H. / Transitional shock wave boundary layer interactions on a compression ramp at mach 4. AIAA Scitech 2019 Forum. American Institute of Aeronautics and Astronautics Inc, AIAA, 2019. (AIAA Scitech 2019 Forum).
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