Characterization of the Structure and Dynamics of Shock-Wave/Transitional Boundary-Layer Interactions
Abstract
Shock-wave/boundary-layer interactions (SWBLI) are a fundamental unsteady flow phenomenon ubiquitous on high-speed vehicles and have thus been a focus of active research for many years.Even the most basic configurations generate SWBLI which, uncontrolled, can lead to high thermal and acoustic loads, and potentially vehicle failure.1 SWBLI in laminar and turbulent boundary layers have been studied extensively over the past several decades, with many review articles published.2-10 However, investigations of SWBLI in transitional boundary layers (XSWBLI) have been sparse in the existing literature.11-15 Understanding the dynamic behavior of such interactions is critically important for the development of high-speed weapons and projectiles since for such smaller bodies it is anticipated that a much higher percentage of the vehicle boundary layer will be in a transitionalstate compared to larger vehicles.To address this gap in the aerothermodynamic knowledge base, a comprehensive three-year experimental and computational initiative to begin a systematic characterization of the structure, dynamic behavior, and scaling parameters of such interactions was undertaken by a team led bythe University of Tennessee under ONR support.16-24 Following this initial characterization of the unsteadiness and structure of transitional interactions, much remains to be learned about the complex dynamics of this critical phenomenon. While the initial effort was successful in characterizing the scaling and dynamics of cylinder-generated XSWBLI over a range of freestreamconditions, significant work remains to fully understand the differences between transitional and turbulent interactions and the role of the incoming boundary layer. Therefore, a renewal effort is proposed to examine these issues through a thorough investigation of the dynamic behavior and scaling of XSWBLI generated by an axisymmetric hollow-cylinder-flare. A focal point of this study will be an analysis of the unsteady shock motion that will determine if the narrow-bandunsteadiness previously observed for cylinder-generated XSWBLI is present for a broader class of shock generators. The investigating team also hopes to identify the dominant instability mechanism driving XSWBLI unsteadiness and locate the physical source of the upstream influence shock that has been observed for XSWBLI. Experimental measurements of surfaceheating rates arising from XSWBLI will similarly be a priority, as shock-generated heating is a primary concern in the development of future hypersonic systems. As in the preceding effort, the team is proposing an integrated experimental and computational investigation of the fundamental behavior of SWBLIs generated within transitional and turbulent boundary layers, but with the intent to probe deeper into the relationship between the incomingboundary layer state and interaction characteristics. The interaction produced by the more general hollow-cylinder-flare shock generator will be investigated at a higher Mach number (Mach 4) and greater model physical scale than in earlier experiments. As in the original investigation, the investigating team plans to work closely with NASA Langley researchers and conduct complementary experiments in the Langley Mach 6 and 10 facilities under the recently introducedNASA facility use policy that enables academic access to NASA facilities.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 25, 2019
- Source ID
- N000141912242
Entities
People
- John D. Schmisseur
Organizations
- Office of Naval Research
- United States Navy
- University of Tennessee