# Modeling and Simulation Group Meeting Old

#### Brownian Dynamics with Constraints

**Speaker:**
Brennan Sprinkle

**Location:**
Warren Weaver Hall 1314

**Date:**
Thursday, February 4, 2021, 12:30 p.m.

**Synopsis:**

At the scale of a few micrometers, objects suspended in a fluid are subject to random kicks from collisions with the solvent molecules. This leads to a random motion of the suspended objects, which must be reconciled with any geometric or mechanical constraints like rigidity or inextensibility. After discussing numerical methods to simulate the Brownian dynamics of rigid bodies, I will primarily focus on simulation methods for inextensible filaments. Filaments at the cellular scale can take the form of beating flagella that propel sperm cells and bacteria; or they can tangle into the vast, interconnected networks that make up the cellular cytoskeleton. I’ll introduce a method where fibers are treated as a chain of beads and use it to interrogate experimental observations on magnetic filaments which can be made to swim using an applied field. Motivated by this study, I’ll present ongoing work concerning a method more suited to fiber networks in which inextensible fiber motions are parametrized as curves on the unit sphere.