Bio-fluid dynamics (Flexible bodies interacting with flowing fluids)

Abstract

Understanding how flexible bodies interact with a surrounding fluid flow is central to understanding many fascinating problems in nature and technology. For example, flexible tree-leaves can deform into conical shapes under a strong wind, reducing their cross-section and hence their drag on the tree. The buckling of small flexible fibers in a flowing fluid can induce non-Newtonian responses, which is important for understanding complex fluids, and for the biophysics of bio-polymers. These are prototype examples of how compliant bodies interact with flowing fluids. As problems in scientific computing they are especially hard to simulate, and require special methods. The flows are incompressible, and the domain is usually time-dependent. The domain boundary exerts forces on the fluid, and vice versa, and these forces often involve constraints or surface curvature, making them sources of numerical stiffness. I will show how careful simulation has shed light on the nature of flow/body interactions, helping to interpret experiments and to guide theoretical explanations.