Computational Models of Self-Propelled Microorganisms

Many interesting biological phenomena involve rigid or flexible thin filaments interacting with a fluid. Some examples are the motion of bacteria swimming through the actuation of flagella, the coordinated motion of cilia, the swimming of spermatozoa, and artificial self-propelled microswimmers. Of particular interest is the interaction of filaments with nearby surfaces or moving through regions in the fluid containing elastic polymers, since these environments are commonly found in nature.  I will present work on computational models of microscopic filaments moving in a fluid based on recent advances of the method of regularized Stokeslets. The method is based on fundamental solutions of linear partial differential equations, modified to remove the singularities. I will show results from simulations of flagellar motions with asymmetric beat patterns and the effect of swimming near a solid surface. Recent work on models of swimming through viscoelastic regions incorporate the effect of the elastic polymers immersed in the fluid using a network of cross-linked nodes where each link is modeled by a simple viscoelastic element. The presentation will be expository; no previous experience in computational fluid dynamics or biological flows is necessary.