This talk will start by introducing diverse fluid-mechanics research conducted in the Multiphysics and Multiscale Fluid Dynamics Lab at Nebraska, including complex fluids, rheology, electrokinetics, laminar-turbulent transition, and turbulence. I will then focus on two projects at very different flow regimes. The modeling, analysis, and computation will be presented for both projects, along with their engineering applications. The first project is dedicated to Stokes flow or microhydrodynamics, where dynamics and rheology of concentrated suspensions of conductive microparticles driven by an electric field are investigated. Notably, the negative particle pressure is found to arise at high concentrations, which could be considered a first-of-its-kind in such particle systems. I will provide applications exploiting this negative pressure, such as for flow battery slurries and desalination. The second project is dedicated to a turbulent flow, where three flow-control methods are investigated to elucidate their underlying drag-reduction mechanisms. These methods include adding long-chain polymers, utilizing hydrophobic surfaces, and imposing an external body force. A temporal analysis based on intermittent high-drag and low-drag periods is employed and shows that the polymer and hydrophobic methods exhibit a similar mechanism, while the body force method is very distinct. I will conclude by providing an implication of these different mechanisms as smart flow control.
About the Speaker
Dr. Jae Sung Park is an Assistant Professor and a director of the Multiphysics and Multiscale Fluid Dynamics Lab in the Department of Mechanical and Materials Engineering at the University of Nebraska-Lincoln (UNL). He was awarded the NSF CAREER Award in 2021 and the UNL College of Engineering New Faculty Teaching Award in 2020. His research centers around fluid flow problems in energy science, advanced manufacturing, environmental engineering, and nano/micro/biotechnology, encompassing a wide range of scales from low to high Reynolds number flows. His research projects have been supported by the National Science Foundation, the Department of Energy, and NASA Nebraska, among other sources. He received his B.S. (2006) from Hanyang University in S. Korea and his M.S. (2008) and Ph.D. (2012) from the University of Illinois at Urbana-Champaign. All degrees are in Mechanical Engineering. Prior to joining UNL in January 2017, Dr. Park was a postdoctoral researcher in the Department of Chemical and Biological Engineering at the University of Wisconsin-Madison.
Host: Professor Leonardo Chamorro