2006 Condensed Matter and Applied Physics Colloquium Condensed Matter and Applied Physics Colloquium Division of Engineering and Applied Sciences Harvard University "Diffusing, Growing, Swimming: Multiscale Simulations using Particles" Petros Koumoutsakos ICOS - Institute of Computational Science ETH Zurich 4:00 p.m, Friday, December 8, 2006 Pierce Hall, Room 209 Abstract: What can we learn about a cell's endoplasmic reticulum from astrophysics simulations? How can we harness 100,000 processors for the study of cancer? How can we harvest energy from an eel? We will address these questions as we explore the dynamics of complex physical systems that emerge in the fields of biology, fluid mechanics, nanotechnology and their interfaces. Our computational investigations rely on novel, multiscale, particle methods that address common computational challenges across diverse physical problems. Particle methods involve computational elements with time dependent properties and entail a broad class of computational schemes ranging from molecular dynamics to vortex methods. We present enhancements to the classical method in order : to accurately simulate processes with complex, deforming geometries (as in diffusion in the endoplasmic reticulum, tumor growth and eel swimming), to resolve systems requiring computational adaptivity and multiresolution interface capturing in astrophysics and two phase flows) and to couple stochastic and deterministic models of multiscale systems (spatial modeling of biological networks and nanotubes in dense fluids). We will discuss insights that have been gained by our computational investigations, including the role of geometry in estimates of diffusion constants in cell organelles and the link between swimming modes and energetics of anguiliform swimmers. website: www.icos.ethz.ch/cse/people/koumoutsakos _______________________________________________ iic-seminars mailing list iic-seminars(a)calists.harvard.edu http://calists.harvard.edu/mailman/listinfo/iic-seminars