The things that keep me up at night

Questions about my work? Email me at gregory.leclaire.wagner@gmail.com. See my github for real-time updates on my software projects.

Turbulent surface boundary layers

I am working on developing models for turbulence in the ocean’s surface boundary layer with ‘optimized’ and uncertainty-quantified parameters. This work is part of the CliMa project.

Squeeze dispersion

Squeeze dispersion is a phenomenon by which the dispersion of tracers is enhanced in the presence of fluctuating strain. This process is important in systems where mixing is inherently diffusive — for example, oceanic mixing across density surfaces. This work shows that averages of diffusivity tend to underestimate the ‘true’ diffusivity that is obtained by ‘correctly’ averaging and normalizing tracer flux estimates in the presence of strain.

Internal waves and currents

Subsurface internal waves modify the physics of quasi-geostrophic eddies and turbulence on scales from 10 to 100 km — the ocean’s version of storms and cyclones — that play a crucial role in transporting heat and carbon from equator to pole and determining the ocean’s density structure. The precise nature and importance of these interactions in the Earth’s ocean, and the role that waves play in transporting oceanic tracers, is poorly understood.

[Oceananigans.jl]

[Oceananigans.jl] is a fast and friendly solver for the direct and large eddy simulation of ocean-relevant fluids problems in julia and using the MITgcm algorithm. I contribute to the development of [Oceananigans.jl] as part of the CliMa project.

dedaLES

dedaLES is python software that uses the dedalus framework to provide solvers for Large Eddy Simulation of turbulence systems on both laptops and supercomputers. dedaLES is modular, so that fluid models (compressible turbulence, stratified turbulence, etc) and turbulence closures can be easily mixed and matched. My goal is to use dedaLES to model turbulence mixing in the oceanic surface boundary layer. I am developing dedaLES with Keaton Burns.

FourierFlows.jl

FourierFlows.jl is julia software that solves ‘small’ 2D fluid dynamics problems on CPUs and GPUs. I am developing FourierFlows.jl with Navid Constantinou.