# Graduate Student / Postdoc Seminar

#### High-Order Boundary Integral Algorithms for Soft Particles in Stokesian Flow

**Speaker:**
Abtin Rahimian

**Location:**
Warren Weaver Hall 1302

**Date:**
Friday, April 17, 2015, 1 p.m.

**Synopsis:**

I will present fast schemes for the simulation of suspensions of deformable particles in Newtonian fluids at vanishing Reynolds number. Soft particles are modeled as vesicles, which are locally-inextensible membranes that resist bending. Vesicles are used as basic models of cell membranes, intracellular organelles, and viral particles. The vesicles' shapes are evolved as a result of interplay between bending and tensile interfacial forces, hydrodynamic interaction between vesicles, as well as the fluid flow, which is governed by Stokes equation.

Simulations of such flows require algorithms for highly stiff, nonlocal, and nonlinear interfacial forces. Semi-implicit time stepping schemes coupled with spectral representation of the surface, reparametrization scheme to avoid extreme mesh distortion, and anti-aliasing techniques enables us to overcome numerical instabilities. We will review these computational components that are essential for simulating large number of particles in dense suspensions.

This is joint work with Bryan Quaife (ICES, University of Texas), Libin Lu (CIMS), Shravan K. Veerapaneni (University of Michigan), George Biros (ICES, University of Texas), and Denis Zorin (CIMS)