The Mechanics of Undulatory Swimming

Friday, January 29, 1999 - 9:30am - 10:30am
Keller 3-180
Chris Jordan (University of Colorado)
Swimming with whole body undulations involves a mechanical interaction between the organism's tissues and its fluid surroundings. Unfortunately, we do not fully understand the form of this interaction, nor do we understand how variation in an organism's morphology and physiology may affect this interaction. It is readily apparent that the internal and external components of the swimming system are tightly coupled, and that the coupling plays a major role in determining the swimming behavior exhibited by whole body undulators. However, it is the coupled nature of the internal and external mechanics that makes the problem so challenging. Studied in isolation, the internal and external mechanical components of the swimming system may not be representative of their in situ behavior. To address this issue, as well as the form of the coupling and its sensitivity to the organism's morphology and physiology, I am taking a number of approaches. One, the `virtual leech', is a mathematical model of a flexible body constructed from elements that have the mechanical properties of both active and passive biological materials. The model is coupled to a simplistic representation of a fluid, however the approach explicitly accounts for the internal and external mechanics, as well as their interactions. Other approaches are essentially refinements on the above model: a finite-element representation of a soft-bodied organism coupled to a Navier-Stokes fluid solver, and a mechanical undulator with prescribed morphology, kinematics and swimming speed with which I can measure the fluid-body interactions as a function of body form and swimming kinematics.