This CAREER project comprises an experimental investigation of the dynamics of granular materials. The research will seek data describing granular flow. This information should aid development of models granular systems. At present there exists no well-established hydrodynamic description of the response of a granular system to external forces. Unlike the situation in conventional, correlations in spatial structure and dynamical quantities may play a significant role in granular flows. A first step to understanding these correlations involves experiments to study and control the dissipative interaction between grains. In parallel, homogeneously excited granular systems will be created via gravity-driven flow and high-amplitude, high-frequency oscillation. These two components will be united to create well-controlled uniform dynamical systems with tunable dissipation, to be studied by video microscopy, diffusing-wave spectroscopy, sound propagation and direct stress measurements with a view to discerning dynamical and spatial correlations. The research plan is structured to build in a significant role for undergraduate research. Some components of the program will devolve into modules for undergraduate laboratory courses. Proposals for course development are defined which build on the research interests and training of the PI to meet departmental goals in an ongoing restructuring of the undergraduate program. %%% This CAREER project comprises an experimental investigation of the dynamics of granular materials. There exists no well-established description of the response of a granular system to external forces at the level of fluid mechanics for conventional liquids. This general question is of interest to a number of scientific communities including chemical and mechanical engineering, geophysics, applied mathematics as well as physics. Unlike the case of conventional fluid flows, correlations in spatial structure and dynamical quantities may play a very significant role in granular flows. The proposed experiments will study homogenous granular flows in which the energy losses are controllable, using a variety of optical techniques, sound propagation and force measurements with a view to discerning dynamical and spatial correlations. The research plan is structured to build in a significant role for undergraduate research with well-delineated projects for independent research. Some components of the program are designed to devolve into modules for undergraduate laboratory courses. Proposals for course development are defined which build on the research interests and training of the PI to meet significant departmental goals as part of an ongoing restructuring of the undergraduate program. ***
