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Dynamics of swept shock-wave/turbulent-boundary-layer interactions

Event Type: 
Date and Time: 
Friday, November 1, 2019 - 16:30
Location: 
CTR Conference Room 103
Event Sponsor: 
Parviz Moin, Director of Center for Turbulence Research
Speaker(s): 
Dr. Michael Adler

Swept shock-wave/turbulent-boundary-layer interactions (STBLIs) exhibit key dynamical differences from their spanwise-homogeneous counterparts, including the suppression of a dominant mechanism of low-frequency unsteadiness. An extensive database of wall-resolved simulations is constructed to examine the differences between the properties of spanwise-homogeneous, swept, and compound swept interaction classes. A novel method for calculating the dynamic linear response of these unsteady flows is also presented, which allows for the identification and characterization of absolute instabilities in the time-resolved turbulent flow, and the ramifications for STBLI dynamics are discussed. The spanwise homogeneous interaction exhibits an absolute instability that is well-correlated with the prominent band of low-frequency unsteadiness, whereas an absolute instability is not present in the simple swept interaction, which exhibits a muted low-frequency band. Further, a relationship between interaction symmetry, separation topology, and low-frequency unsteadiness is described, in which the prominent low-frequency unsteadiness is spatially associated with surface-flow singular points that function to topologically close the separation. For swept interactions, the ramifications of quasi-conical interaction symmetry on the frequency scaling of the shear layer bands are also discussed. In essence, the shear layers of the swept interactions exhibit a mix between classical and conical free-interaction scaling in both mean flow and frequency content.

Bio: 
Dr. Michael Adler received his PhD in Aeronautical and Astronautical Engineering from The Ohio State University in 2019, where his research examined many aspects of shock-wave/turbulent-boundary-layer interactions with Prof. Datta Gaitonde. He has recently joined CTR as a postdoctoral fellow and works with Prof. Sanjiva Lele on numerical methods for shock/material-interface interactions and elastic-plastic flow phenomena, including the Richtmyer-Meshkov and other instabilities of elastic-plastic flows.