Levich Institute Seminar Announcement, 11/17/2009
Tuesday, 11/17/2009
2:00 PM
Steinman Hall, Room #312
(Chemical Engineering Conference Room)

Professor Daniel Goldman
Georgia Institute of Technology
School of Physics

"Biophysics in the Sandbox: The Mechanics of Swimming of the Sandfish"


ABSTRACT


The desert dwelling sandfish lizard burrows into dry sand, a granular material that displays solid and fluid-like behavior, in under a half-second and swims through it at speeds up to 1.5 bodylengths/sec (Maladen et. al, Science, 2009). High speed x-ray imaging shows that below the surface the lizard no longer uses limbs for propulsion but generates thrust to overcome drag by propagating an undulatory traveling wave down the body. While viscous hydrodynamics can predict swimming speed in fluids like water, an equivalent theory for granular drag is not available. To predict sandfish swimming speed, we develop an empirical model by measuring drag force on a small cylinder oriented at different angles relative to the displacement direction and summing these forces over the animal movement profile. The agreement between model and experiment implies that the non-inertial swimming occurs in a frictional fluid.

BRIEF ACADEMIC/EMPLOYMENT BACKGROUND:

  • Massachusetts Institute of Technology, Cambridge, MA S.B. in Physics, 5/94
  • University of Texas at Austin, Austin, TX Ph.D. in Physics, 8/02
  • Assistant Professor of Physics School of Physics, Georgia Institute of Technology, Atlanta, GA 1/07-present

CURRENT RESEARCH INTERESTS:

My research integrates my work in complex fluids and granular media and the biomechanics of locomotion of organisms and robots to address problems in nonequilibrium systems that involve interaction of matter with complex media.