Title:

Modeling the influence of buoyancy: implications for mixing and transport in natural waters and the atmosphere

Abstract:

The dynamics of stratified fluids in Earth's waters and atmosphere play a key role in shaping our weather, climate and the quality of the air and water around us. Variations in flow buoyancy can drive a wide range of behaviors, with important consequences for how heat and particles move through natural systems. In this talk, I will use high-resolution numerical simulations to explore the physics behind these processes in several classes buoyancy-driven flows.

The first class of flows I consider are governed by a quadratic equation of state (EOS), where water of different temperatures but the same density can mix through a process called cabbeling. I'll show cabbeling affects heat transport in cool fluid systems and how it helps us to understand mixing within ice-covered freshwater lakes.

Next, I will consider a class of flows where thermal and mechanical forces are of similar strength - a regime known as turbulent mixed convection. Here, I'll discuss how turbulent structures influence the emission and dispersion of settling particles, and how those dynamics depend on both the flow and particles characteristics. Together, these results offer a glimpse into the small-scale mechanisms that control dust emission and dispersion in the atmospheric surface layer.

Bio:

Grace joined the Department of Applied Mathematics in 2025. He previously held concurrent NSERC and ND-ECI postdoctoral fellowships at the University of Notre Dame after completing his graduate work at the University of Waterloo. 

His research interests lie broadly in computational fluid mechanics. Grace is motivated by applications of turbulent and quasi-turbulent fluid flows, specifically relating to the transport of heat and other materials in natural systems.