Near-Field Dynamics, Mixing, and Sediment Transport in Freshwater Plumes
A Warren Distinguished Lecture with
Cristián Escauriaza
Hydraulic and Environmental Engineering
Pontificia Universidad Católica de Chile
Pontificia Universidad Católica de Chile
ABSTRACT
Freshwater plumes from small rivers play a central role in coastal mixing and entrainment by introducing buoyant, turbulent flows into a stratified ocean. In glacial systems such as those in Patagonia, strong salinity stratification and energetic near-field dynamics give rise to sharp density interfaces and coherent flow structures that regulate how plumes spread, mix, and exchange mass with the ambient fluid for a wide range of spatial and temporal scales.
Cristián Escauriaza presents results from an ongoing project that uses direct numerical simulations (DNS) to examine the near-field dynamics of freshwater plumes under subcritical and supercritical conditions. The simulations resolve the 3D structure of stratified turbulence and reveal transitions between shear-driven instability regimes that control entrainment and mixing efficiency. Escauriaza focuses on how coherent vortical structures and interfacial instabilities organize vertical exchange in these flows, and briefly discusses how the inclusion of suspended sediment modifies plume dynamics and feeds back on turbulent mixing. Together, these results provide a view of near-field plume dynamics and help connect idealized turbulence studies with the behavior of glacial river plumes in natural coastal environments.
SPEAKER
Cristián Escauriaza is Associate Professor of Hydraulic and Environmental Engineering at the Pontificia Universidad Católica de Chile. He received his PhD from the University of Minnesota and a MSc from the Georgia Institute of Technology. Cristián’s research focuses on the study of complex flows in nature for a wide range of scales, and on the characterization of transport processes in engineering and earth sciences, including sediment transport and morphodynamics, via numerical simulations, nonlinear dynamics, and statistical analyses. He is an associate researcher of the Center for Integrated Disaster Risk Management (CIGIDEN) and scientific leader of the marine energy center MERIC. He serves as associate editor of the Journal of Geophysical Research-Earth Surface and the ASCE Journal of Hydraulic Engineering. In 2023-2024 he was the Shimizu Visiting Professor in the Department of Civil & Environmental Engineering at Stanford University.
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