Zhi (George) Lin
Department of Mathematics
University of North Carolina at Chapel Hill, 2007
Thesis: Scalar Intermittency in Random Flows: Modelling and Simulation
Advisors: Richard M. McLaughlin, Roberto Camassa
B.S., Applied Mathematics and Applied Software,
South China University of Technology, Guangzhou, China, 2002
Research Interests:Fluid Dynamics, Mixing and Transport, Asymptotic Theory, Stochastic Differential Equations, Mathematical Biology, Numerical Simulations
Recent Articles:ZL, D. Xiao, F. Fang, C.Pain and I.M. Navon, Non-intrusive reduced order modelling with least squares fitting on a sparse grid, Inter. J. Num. Methods Fluids, Submitted.
D. Xiao, ZL, F. Fang, C.Pain, I.M. Navon, P. Salinas and A. Muggeridge, Non-intrusive reduced order modeling for multiphase porous media flows using Smolyak sparse grids, Inter. J. Num. Methods Fluids, Submitted.
ZL, Y. Zhang, Stirring by multiple cylinders in potential flow, J. Fluid Mech., 794: 552--564
R. Camassa, ZL, R.M. McLaughlin, K. Mertens, C. Tzou, J. Walsh, B. White, Optimal mixing of buoyant jets and plumes in stratified fluids: theory and experiments, J. Fluid Mech., 790: 71--103
E. Lunasin, ZL, A. Novikov, A. Mazzucato, and C. R. Doering, Optimal mixing and optimal stirring for fixed energy, fixed power or fixed palenstrophy flows, J. Math. Phys., 53(11): 115611 (2012).
Research Highlights (Poster PDF)
My research revolves around and evolves from the fundamental problem of mixing and transport in fluids. Using a variety of mathematical tools that include partial differential equations, perturbation theory, asymptotic methods, variational calculus, numerical analysis, optimization and statistics, I focus on the understanding and exploitation of various mixing and transport phenomena that arise in geophysical, biological and mechanical systems. These phenomena are often characterized by the behavior of fluctuations fields of submerged physical observables, many of which can be modeled as passive scalars, such as temperature, moisture, chemical concentrations. These quantities not only are the subject matters in environmental control, combustion, and biochemical reactions but also serve as proxies for the study of turbulence.
During my Ph.D. study at the University of North Carolina, I was a Research Assistant supported by the NSF award "Collaborations in Mathematical Geosciences (CMG)". My thesis on passive scalar intermittency under the guidance of Professor Richard McLaughlin and Professor Roberto Camassa focused on identifying the physics responsible for the non-Gaussian statistics observed for many physical quantities in experimental and natural turbulence. I also worked in the UNC Fluids Lab and analyzed data on underwater turbulent plumes and jets whose behavior may have great environmental impacts.
After my graduation, I started my postdoctoral research at the University of Michigan funded through the NSF award "Studies in Mathematical Physics (PHY)". With the help of my faculty mentor, Professor Charles Doering, I integrated my expertise in asymptotic, variational and stochastic methods and reconciled previously conflicting results on flow-enhanced scalar diffusion by addressing the different physical mechanisms and mathematical challenges. Since I became a Postdoctoral Fellow for the IMA Thematic Year on Complex Fluids and Complex Flows, I have extended my work seeking to optimize industrial and microfluidic mixing. Additionally, I started to explore the biological applications of my knowledge with research projects in biogenic mixing. Furthermore, I have been consistently inspired by interacting with physicists, environmental scientists and engineers through various conferences and workshops, including the notable Geophysical Fluid Dynamics Summer Program at the Woods Hole Oceanographic Institution that has beening going on for more than half a century now.