Conference by Professor Howard Stone (Thursday October 20th, 3 pm )

Microhydrodynamic problems inspired by blood:(i) Representative subsampling during sedimentation and (ii) Motions near rough boundaries

Conference byProfessor Howard Stone

Princeton University (USA)

Visiting Professor of the KIM IBS

Abstract:The handling of blood, and similar particle-laden complex fluids, raises a variety of different problems in microhydrodynamics. In this talk, I discuss several problems we have studied in recent years. In the first part of this I talk, I describe work we did motivated by the many cases where a small amount of a suspension, such as blood,  is extracted from a larger sample of the same material for the purposes of diagnostics, testing or imaging. A practical challenge is that the cells in blood sediment noticeably on the time scale of a few minutes, making representative subsampling of the original sample challenging.

We developed a Kynch sedimentation model to discuss design considerations that ensure a representative subsampling of blood for the entire range of physiologically relevant hematocrit over a specified time of interest. In the rest of the talk I describe the hydrodynamic interactions between sedimenting spherical particles and nearby corrugated (or rough) surfaces, e.g., the corrugations can be tilted with respect to gravity. Our experiments show three-dimensional, helical particle trajectories with an overall drift along the corrugations, which agree quantitatively with our analytical perturbation theory. The extension to chemical dispersion in these kinds of roughness-induced flows is described also.

Professor Howard Stonereceived the B.S. degree in Chemical Engineering from UC Davis in 1982 and the PhD in Chemical Engineering from Caltech in 1988. Following a postdoctoral fellowship at the University of Cambridge, in 1989 Howard joined the faculty of the (now) School of Engineering and Applied Sciences at Harvard University, where he eventually became the Vicky Joseph Professor of Engineering and Applied Mathematics. In July 2009 Howard moved to Princeton University where he is Donald R. Dixon ’69 and Elizabeth W. Dixon Professor in Mechanical and Aerospace Engineering.

Professor Stone’s research interests are in fluid dynamics, especially as they arise in research and applications at the interface of engineering, chemistry, physics, and biology. He is a Fellow of the American Physical Society (APS), and is past Chair of the Division of Fluid Dynamics of the APS. Currently he is on the editorial or advisory boards of Physical Review Fluids, Langmuir, and Soft Matter, and is co-editor of the Soft Matter Book Series.  He is the first recipient of the G.K. Batchelor Prize in Fluid Dynamics (2008). He was elected to the National Academy of Engineering in 2009, the American Academy of Arts and Sciences in 2011, the National Academy of Sciences in 2014, the Royal Society of the UK (foreign member) in 2022, and the American Philosophical Society in 2022.