The 2021 Lewis Fry Richardson Medal is awarded to Bérengère Dubrulle for outstanding contributions to the field of geophysical and astrophysical turbulence, and for a unique approach to the study of experimental turbulent flows using statistical mechanics.
Bérengère Dubrulle bridges theoretical physics and geophysical and astrophysical systems in a fluid-dynamical turbulence framework, with a broad range of applications: astrophysical disks, atmospheric boundary layers, generation of magnetic fields in the universe, and atmospheric circulation patterns, as well as climate variability. Dubrulle has been at the forefront of turbulence research, studying for example local, extreme energy-dissipation events in such flows as emblematic of a possible route to finite-time singularity in the Navier-Stokes equations. This central question in classical physics has potentially significant implications for the modern practices of computational simulations of Earth’s and astrophysical circulation systems.
Dubrulle’s universe-in-vitro experiments led to the formulation of a new solar system formation scenario. Her idea was that the dissipation observed in a laboratory Taylor-Couette flow, properly rescaled, was sufficient to describe the dissipation observed in proto-planetary disks. Dubrulle has also shown that the structure of the atmospheric planetary boundary layer can be obtained as a natural generalization of these results to the Boussinesq equations.
Another of Dubrulle’s groundbreaking contributions concerns the modelling of turbulent flows by means of statistical mechanics. This work predicted theoretically and confirmed experimentally a rich variety of turbulent states in von Kàrmàn swirling flows, novel phase transitions between them being reminiscent of the critical transitions observed in systems at equilibrium, like para-ferromagnetic transitions with rich dynamics of oscillatory or chaotic regimes. Beyond turbulence, her work has been successfully applied in the climate sciences by uncovering relations between blocked atmospheric flows and unstable fixed points in atmospheric dynamics.
Dubrulle also has exemplary activity in the education of younger scientists and takes a very active role in the dissemination of science. She has authored a children’s book on science, she has given numerous talks in classrooms, and she has also participated in book festivals.