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MEAM Seminar: “Dynamical Systems Approach to Geophysical and Aerospace Flows”
September 10, 2019 at 10:30 AM - 12:00 PM
A dynamical systems approach is taken to explain the dynamics of two classes of ‘gap-leaping’ geophysical flow as well as the hypersonic second-mode instability. First, in the context of a loop current system, it is shown that multiple steady flow patterns with hysteresis exist and appear to satisfy a cusp catastrophe geometry of solutions. Which state the system assumes (looping or leaping or periodic eddy shedding) and when transitions between states occur, will be discussed in terms of fundamental vorticity advection and dissipation. Second, a global perspective of Gulf of Maine circulation leads to a new mechanism for Scotian Shelf Water crossover events. Finally, by considering an idealized system and an analogy with harmonic oscillators, a fundamental mechanism for the hypersonic second-mode instability is proposed.
Assistant Professor of Mechanical Engineering, University of Delaware
Joseph Kuehl is an Assistant Professor at the University of Delaware in the Mechanical Engineering Department. He holds Ph.D.s in Physical Oceanography and Mechanical Engineering from the Graduate school of Oceanography and University of Rhode (2009). His research interests include geophysical fluid dynamics (gap-leaping boundary currents, geophysical boundary layer dynamics and transport phenomena), hypersonic boundary-layer stability (numerical laminar-turbulent transition) and nonlinear vibrations (time series analysis, modal decomposition techniques and finite time invariant manifold analysis). He was the recipient of the AFOSR Young Investigator Award (2015) for his hypersonic boundary layer stability and transition research, participates in the NATO STO ET-190 hypersonic vehicle working group and was a member of the National Academy of Science Committee on Advancing Understanding of the Gulf of Mexico Loop Current Dynamics.