Summary: Atmospheric flows on rotating planets are prone to form jets that are surprisingly stable in time. This behaviour can be predicted by simulating the planet's atmosphere numerically. In certain parameter regimes, the underlying dynamical system has multiple locally stable solutions, corresponding to atmosphere configurations with different numbers of jets. Similarly, the onset of turbulence in a pipe happens in a drastically different manner than other phase transitions: Large scale turbulent areas, so-called puffs, are excited and then very long lived, and the transition to turbulence manifests in these puffs spontaneously splitting into a cascade of daugther-puffs. This project explores the mechanisms by which random fluctuations in turbulent flow drive the system to transition between these fixed points, effectively creating or destroying atmospheric jets or turbulent flows in a pipe in the process.
Relevant publications
-
A. Frishman, and T. Grafke, "Dynamical landscape of transitional pipe flow", Phys Rev E 105 (2022), 045108 (link)
-
A. Frishman, and T. Grafke, "Mechanism for turbulence proliferation in subcritical flows", Proc. R. Soc. A 478 (2022), 2265 (link)
-
J. E. Sprittles, J. Liu, D. A. Lockerby, T. Grafke, "Rogue nanowaves: A route to film rupture", Phys. Rev. Fluids 8 (2023), L092001 (link)
-
J. Liu, J. E. Sprittles, T. Grafke, "Mean First Passage Times and Eyring-Kramers formula for Fluctuating Hydrodynamics", J. Stat. Mech. 2024 (2024), 103206 (link)
-
Paolo Bernuzzi, Tobias Grafke, "Large Deviation Minimisers for Stochastic Partial Differential Equations with Degenerate Noise", ArXiv (2024) (link)