Simulation of Flexible Fibers in Stokes Flow

When elastic fibers are immersed in a Newtonian fluid, the behavior of the system, or the “fiber suspension” becomes non-Newtonian. Understanding the dynamics of such systems is of particular interest in a wide variety of fields, including locomotion of microorganisms, paper and pulp industry, microfluidics etc. When these fibers are immersed in the fluid at low Reynolds number, the elastic equation for the fibers couples to the Stokes equations, which greatly increases the computational complexity of the problem. I have simulated buckling behavior of a single fiber suspended in a shear flow and have applied two numerical method, a slender body approximation known as Local Drag model and a regularized Boundary Integral method known as Regularized Stokeslet method. We have extended the Local Drag model to simulate naturally bent fibers based on the target or resting curvature of the fibers. Microorganisms possess fiber-like organs known as the appendages and swim by flapping these organs. We have also simulated swimming motion of a simple microorganism model by imposing a time dependent resting curvature of these fibers.