Presenter: Colm-cille Patrick Caulfield, Professor, DAMTP, University of Cambridge
Description: Statically stable density stratification is ubiquitous in geophysical flows, with the atmosphere, lakes and oceans all typically having an average density distribution that decreases upwards in a gravitational field. Due to the associated stabilising effect of the buoyancy force, it would seem intuitive that such statically stable density distributions should suppress vertical motions, relative to horizontal motions. Such inevitable anisotropy complicates even further developing an understanding of turbulence in density-stratified fluids. Stratified turbulence is not just a fascinating (and inherently complicated) research challenge in classical physics, but also a key component of the global climate system, as stratified turbulence has a leading order effect on the transport of heat and other scalars such as carbon dioxide, pollutants etc in the world’s oceans and atmosphere. Indeed, how stratified turbulence can actually be `born’ and then `survive’ for a significant period, hence irreversibly mixing significant scalar quantities, are open questions, associated with ongoing controversy in the global research community. In this talk, I will review some recent studies by my collaborators that have advanced our understanding of various key properties of stratified turbulence and mixing, while also demonstrating that there is still much more to learn about this fascinating and vitally important class of fluid flows.
Bio: Colm-cille P. Caulfield is Professor of Environmental and Industrial Fluid Dynamics in the Department of Applied Mathematics and Theoretical Physics (DAMTP) at the University of Cambridge, and a faculty member of the Institute for Energy and Environmental Flows (IEEF). He is also a Professorial Fellow in Mathematics at Churchill College, Cambridge, and the Co-Director (Science) of the University’s Institute of Computing for Climate Science (ICCS), which studies and supports the role of software engineering, computer science, AI and data science within climate science. Prof. Caulfield’s personal research interests include instability, turbulence transition and turbulent mixing processes in stratified flows, with particular focus on understanding and improving the modelling of heat transport in the world’s oceans. His undergraduate studies were at the University of Ulster at Coleraine, graduating with a BSc in Mathematics in 1987. He then studied for his Masters and PhD in Fluid Mechanics at DAMTP under the supervision of Prof Paul Linden FRS, defending his thesis on stratified shear instabilities in 1991. Following postdoctoral training in the Department of Physics at the University of Toronto and the Department of Engineering Science at Hokkaido University, he was a lecturer in the School of Mathematics at the University of Bristol from January 1995 to June 1999. Prof. Caulfield subsequently joined the faculty of the Department of Mechanical and Aerospace Engineering at the University of California, San Diego for the period July 1999 to June 2005. Following tenure at UCSD, Prof. Caulfield joined the BP Institute (now IEEF) and DAMTP in July 2005. Prof. Caulfield is the Editor-in-Chief of the Journal of Fluid Mechanics, the Chair of the European Mechanics Society (Euromech) Turbulence Conference Committee, and served as the Head (ie Dept Chair) of DAMTP January 2020-September 2025. He was elected a Fellow of the American Physical Society (Division of Fluid Dynamics) in 2014.
Hosted by: Professor Julie Simons
