Animals - Colloquium
Monday, February 26, 2007
4:00 PM-5:00 PM
Olin Hall
107
Foams and granular materials are two fundamental model systems of complex fluids studied by soft condensed matter physicists. A common feature is their cellular structure, which consists of bubbles and grains respectively. Their particle sizes exceed microns, and therefore at rest these materials are jammed, athermal systems. The packing and shearing of these cellular elements and their micro-scale interactions lead to fascinating macroscopic continuum-type behaviors. Familiar examples include foam drainage of freshly-poured beer and the sudden onset of granular flow causing landslides. The mechanical properties of these complex fluids span a large dynamical range of continuum behavior and include elasticity, viscosity and plasticity.
I will compare and contrast behaviors of foams and granular materials based upon various experiments performed in my lab. I will discuss the similarity between Darcy flow through soils and foam drainage in the limit of large surface viscosity. Moreover, foams and granular particles have similar rheological behaviors, which depend on pressure between particles, shearing rates and shearing displacements. For example, both systems are prone to shear band formation, and have a finite yield stress. I will conclude with recent experimental results for self-propulsion that were inspired by sand-swimming animals such as desert vipers and lizards.
Cost: FREE
Sponsored by: WPI Physics Department, Dr. Stephen Jasperson
Suggested Audiences: College
E-mail:
snj@wpi.edu
Phone: 508-831-5392
Last Modified: February 2, 2007 at 8:33 AM
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