Events

Complex fluids—including polymer solutions/melts, emulsions, foams, and living cells—exhibit rich rheological behavior such as viscoelasticity, yielding, and aging. These behaviors play a central role in transport, mixing, and processing operations across industrial manufacturing, materials science, and bioengineering. However, predicting and controlling complex-fluid transport under realistic conditions remains challenging due to nonlinear constitutive response, evolving interfaces, and multiscale coupling between microscale structure and macroscopic flow.

In this seminar, I will present three case studies illustrating how theory, computation, and experiment are combined to address central challenges in processes involving complex fluids and biological transport. First, I will examine flows of polymer solutions through model porous media, showing how elasticity and shear-thinning generate flow asymmetries relevant to subsurface transport and filtration. Second, I will discuss polymer melt extrusion and resolve a long-standing puzzle regarding surface instabilities by linking extrudate distortions to intense polymer chain stretching and elastic recoil. Finally, I will leverage continuum modeling to describe centrosomal asters, revealing how cytoskeletal mechanics and intracellular transport interact to regulate eukaryotic cell division.

These examples illustrate how multiscale modeling uncovers principles that advance both fundamental understanding of physical and biological processes and their application to real-world challenges.

Stylianos (Stelios) Varchanis uses theory and computation to understand fundamental transport processes in complex fluids, soft matter, and living systems, with relevance to materials engineering, energy, and biotechnology applications such as advanced polymer manufacturing, enhanced oil recovery, and biomedical devices. His research integrates methodologies inspired by fluid and solid mechanics, rheology, soft matter physics, biophysics, dynamical systems, and computational mechanics, with a strong emphasis on multiscale modeling. As a result, his work is highly interdisciplinary, lying at the intersection of engineering, physics, biology, materials science, and applied mathematics.

He is currently a Flatiron Research Fellow at the Flatiron Institute (Simons Foundation), where he works on active matter and cellular mechanics. Previously, he was a postdoctoral scholar at the Okinawa Institute of Science and Technology in Japan, studying microscale flows of complex fluids. He received his Ph.D., M.Sc., and B.Sc. in Chemical Engineering from the University of Patras, Greece.