Berkeley Fluids Seminar

Horizontal shear instabilities at low Prandtl number

Monday, October 14, 2019

12:00-13:00, 3110 Etcheverry Hall

Prof. Pascale Garaud

(Applied Mathematics at the Baskin School of Engineering, UC Santa Cruz)

Abstract: Professor Garaud will be presenting some of her recent work on the dynamics of horizontal shear instabilities at low Prandtl number, which are particularly relevant in the context of stellar interiors. Using Direct Numerical simulations of body-forced shear flows, it is possible to study this problem ‘in silico’ at numerically achievable parameters, and extrapolate the results to stellar conditions. Professor Garaud will show that horizontal shear flows exhibit rich dynamics, and can cause substantial vertical mixing. Various regimes are found depending on the respective values of the Reynolds, Péclet, and stratification parameter. Professor Garaud will also present the various scaling laws she and her colleagues have been able to infer from the experimental data, and physical justifications for why these scalings are expected to emerge. The talk will conclude with a discussion of potential applications to stellar evolution.

This work was done in collaboration with Laura Cope and Colm-cille Caulfield from DAMTP, Cambridge.

Bio: Pascale Garaud is a Full Professor in the department of Applied Mathematics at the Baskin School of Engineering at UC Santa Cruz. Her research focuses on fluid dynamics and magnetohydrodynamics applied to astrophysics and occasionally geophysics. She specializes in understanding and quantifying mixing processes produced by large-scale fluid flows and magnetic fields, as well as small-scale turbulence. Her work involves a range of applied mathematical tools from numerical experimentation using high-performance computing to pen-and-paper analytical derivations. She is a member of the Fluid Dynamics Group of UCSC, and of the Theoretical Astrophysics at Santa Cruz (TASC) research unit. She recently joined the Editorial Board of Physical Review Fluids and became a Fellow of the American Physical Society in 2019.

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Acknowledgments

Prof. Eliot Quataert on behalf of The Theoretical Astrophysics Center and the Astronomy Department (UC Berkeley)

Prof. Philip S. Marcus on behalf of the Mechanical Engineering Department (UC Berkeley)

Prof. Michael Manga (Earth and Planetary Science, UC Berkeley)

Prof. Evan Variano (Civil and Environmental Engineering, UC Berkeley)