Seminar
Blow Up Chemical Reaction Networks
A vorticity-based mixed formulation for the unsteady Brinkman-Forchheimer equations
In this work we propose and analyze an augmented mixed formulation for the time-dependent Brinkman-Forchheimer equations written in terms of vorticity, velocity and pressure.
The weak formulation is based on the introduction of suitable least squares terms arising from the incompressibility condition and the constitutive equation relating the vorticity and velocity. We establish existence and uniqueness of a solution to
Why general relativity does not admit enough observables
One of the biggest open problems in mathematical physics has been the problem of formulating a complete and consistent theory of quantum gravity. Some of the core technical and epistemological difficulties come from the fact that General Relativity is fundamentally a geometric theory and, as such, it ought to be invariant under change of coordinates by the arbitrary element of the diffeomorphism group Diff(M) of the ambient manifold M.
Why I love Monovariants: From Zombies and Conway's Soldiers to Fibonacci Games
Xiaodan Zhou - Characterization of horizontal quasiconvexity in the Heisenberg group and applications
Viazovska’s work on sphere packings
Leo Rebholz - New results for the NSE in EMAC form
We discuss several recent results for Navier-Stokes equation in EMAC form, including longer time accuracy through an improved Gronwall estimate, a lower bound on error for forms that do not conserve momentum and angular momentum, exact local discrete balances of momentum and angular momentum with EMAC, and lastly the importance of consistency in ROMs for NSE using EMAC.
Javier Cueto - Helmholtz decomposition for (one-point) gradients of fractional order over bounded domains
Optimization and Reduced Order Models for Digital Twins
This talk begins by discussing the role of PDE-constrained optimization in the development of digital twins. In particular, applications to identify weaknesses in structures and aneurysms are considered. Next, we analyze a data-driven optimization problem constrained by Darcy’s law to design a permeability that achieves uniform flow properties despite having nonuniform geometries. We establish well-posedness of the problem, as well as differentiability, which enables the use of rapidly converging, derivative-based optimization methods.