Published on: January 13, 2025
AAE Research Seminar: Michael Wadas - 1/23
AAE Research Seminar: Michael Wadas - 1/23
Event Date: | January 23, 2025 |
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Time: | 10:30 AM - 11:45 AM |
Location: | ARMS 1103 or Webex |
Priority: | No |
College Calendar: | Show |
Vortex Dynamics in Inertial Fusion and Astrophysics
MICHAEL WADAS Faculty Candidate - AAE Open Search
ABSTRACT
The mixing induced by a shock wave passing through a fluid interface can stimulate the ejection of high-velocity projectiles of one fluid into the other. Such projectiles severely disrupt implosion symmetry in inertial confinement fusion and transport stellar core elements during supernovae. Recent improvements in experimental diagnostics and numerical simulations reveal that the projectiles share key characteristics with classical fluid vortex rings, thus enabling a path to understand their dynamics. In the first part of the talk, we examine the ejection of vortex rings from shocked interfaces and determine their scaling through numerical simulations and first-ever physical experiments isolating the formation of high-energy-density vortex rings. Next, we examine related vortex dynamics which may have played a critical role in shaping the circumstellar environment surrounding the famous Supernova 1987A, which consists of evenly spaced gaseous clumps comprising an equatorial ring. Prior to the supernova, the ring may have formed a vortex pair unstable to the Crow instability, well known in aeronautics for dissipating airplane wakes, after acquiring vorticity from the progenitor wind. Our analysis of this instability yields a dominant wavenumber remarkably consistent with the number of observed clumps. Recent observations by the James Webb Space Telescope further confirm the plausibility that the Crow instability induced clump formation. We conclude with a discussion of ongoing work to examine this instability mechanism in protoplanetary disks, where it may be responsible for seeding the formation of planets.
BIOGRAPHY
Michael Wadas is the Cecil and Sally Drinkward Postdoctoral Scholar in the Mechanical & Civil Engineering Department at Caltech, where he is advised by Tim Colonius and Joseph Shepherd. His research combines theory, simulations, and experiments for the study of both high-energy-density and classical fluid flows and has led to techniques for strengthening laser-driven shock waves, an experimental platform for generating vortex rings from shocked interfaces, a novel interpretation of clumping in circumstellar environments, and an enhanced understanding of instability mechanisms in accelerated interfacial flows. Michael received a B.S. in Mechanical Engineering from Purdue University in 2017 and a Ph.D. in Mechanical Engineering from the University of Michigan in 2023.