Turbulence and Thermal Structure in the Upper Ocean: LES Studies

Sutanu Sarkar, Professor, Mechanical and Aerospace Engineering, University of California San Diego

Abstract: The upper layer of the ocean participates directly in the exchange of momentum, heat and moisture with the atmosphere. We consider three examples of upper-ocean flow and heat transfer in the present contribution.  These examples illustrate wind-driven entrainment in a stratified fluid, stratified shear flow turbulence and its response to surface forcing, and the lateral circulation in a frontal jet between two water masses of different density that develops into a gravity current. Our tool is large eddy simulation (LES) which is increasingly being used to examine turbulent transport and mixing in the ocean. We discuss how buoyancy and rotation affects the spatial structure and temporal evolution of turbulent fluxes, and thereby the distribution of momentum and heat in the upper ocean.

About the Speaker: Sutanu Sarkar received his B. Tech from IIT Bombay, M. S. from Ohio State University and Ph. D. from Cornell University. After 4 years as a staff scientist at ICASE, NASA Langley Research Center, he joined UCSD where he is currently the Blasker Professor of Engineering in the department of Mechanical & Aerospace Engineering (MAE) and an affiliate professor at the Scripps Institute of Oceanography. He was Chair of MAE from 2009-2014. He has broad interests in turbulence simulation and modeling and has worked in problems concerning the environment, energy, aerospace and propulsion. His current research interests are turbulence and mixing in the ocean, wakes and boundary layers of engineered structures in the natural environment, and renewable energy. He has received a NASA group achievement award (1994), the Bessel Award from the Humboldt Foundation (2001), and was elected Fellow, American Physical Society (2006), Associate Fellow, AIAA (2009) and Fellow, ASME (2010).