"Can we develop a general theory of the dynamics of turbulent flows and the motion of granular materials?" asked Science magazine on its 125th anniversary. Indeed, the mechanics of granular matter remains an active and alluring field of research in part due to the simplicity with which one can illustrate the puzzling behavior of granular materials in the lab, combined with the difficulty in understanding their theoretical foundations.

In his textbook Statics and Kinematics of Granular Materials, Nedderman estimated that approximately one-half of the products and at least three-quarters of the raw materials in the chemical industry are in granular form, which gives a point of reference for just how ubiquitous granular materials are in the real world. Hence, a better understanding of the fundamental transport processes for granular materials (i.e., diffusion, flow, dispersion, see Figs. 1 and 2), which has been the major goal and significant accomplishment of this project, has the potential to impact other disciplines (beyond applied mathematics and mechanics), such chemical engineering, pharmaceutical industry and even geophysics.

The ability to improve the modeling of granular transport processes also impacts energy applications including storage and transportation of energy-related materials (e.g., coal and biofuel). For example, granular materials tend to segregate according to size, a property that can be undesirable in manufacturing and transportation processes. This project's significant accomplishments address the characteristics of granular flow and, therefore, can lead to the design of optimized containers for efficient transportation. Furthermore, the significant accomplishment of this project in understanding granular "Taylor" dispersion is relevant for industrial separation processes, such as the drying of powders for the purposes of dehydrating food, as well as geological hazards, in which the distribution of debris upon the cessation of an avalanche or landslide can dictate the ecological impact of an event. By providing specific analytical results and scaling laws, we advanced the knowledge base of these seemingly disparate scientific fields.

The major scientific results from this project were written and published as research papers in peer-reviewed journals (both disciplinary journals relevant to the community of interest for this project such as Granular Matter and major interdisciplinary journals such as the Proceedings of the National Academy of Sciences). The results were further disseminated through invited departmental seminars and colloquia at various leading institutions (e.g., Columbia University, the Johns Hopkins University, the University of Oxford, and others).

Last Modified: 10/09/2015
Modified by: Ivan C Christov