Fluid Mechanics Seminar: Eliot Fried

Suspensions of micron-size particles in Newtonian fluids are present in a broad spectrum of biological and engineering applications and understanding their rheological properties is a crucial task. Computational studies of such systems are challenging, but important simplifications occur when the Reynolds number is sufficiently small. In this context, the flow equations become linear and Stokesian dynamics simulations offer a feasible pathway for numerical investigations. We will show how it is possible to apply a box-deformation scheme developed by Andersen, Parrinello, and Rahman in the context of molecular dynamics simulations to the Stokesian dynamics of hard spheres suspended in a Newtonian fluid with fixed background flows. Combining that scheme with the box-reinitialization strategy of Kraynik and Reinelt, a perpetual extensional flow can be simulated. We find that in extensional flows simulations, quantities of rheological interest, such as the effective viscosity of the suspension, are robust against computationally-induced ordering. Such ordering, a well-known spurious effect encountered in shear-flow simulations, is easily suppressed in an extensional background flow simply due to the steric interaction of the hard spheres.

Bio: Eliot Fried obtained his Ph.D. in Applied Mechanics from the California Institute of Technology in 1991. Professor Fried heads the new Mathematical Soft Matter Unit at the Okinawa Institute of Science and Technology. Previously Professor Fried was at the University of Washington, where he was a Professor of Mechanical Engineering and before that he was Professor of Mechanical Engineering, Professor of Mathematics and Statistics and the Tier 1 Canada Research Chair in Interfacial and Defect Mechanics at McGill University. His research is in soft matter, which is the study of materials made of many atomic or molecular parts, which do not act in a way predicted by any one element within the substance. Understanding these materials, which range from blood and tissue to fuel additives and adhesives, and how to manipulate them, can lead to advances in nearly every field of science and engineering.

Please also join us for coffee and cookies before the talk in the PIMS Lounge (ESB 4133)