Hydrodynamic interactions in granular media

Sand is just one example of a much larger family of granular materials that affects our lives constantly. Granular materials play an important part in today´s industries, including mining, agriculture, construction, and pharmaceutical manufacturing. The scientific understanding of how avalanches, landslides, and erosion occur could help us develop ways to detect their occurrence. Granular materials have attracted a considerable amount of attention from scientists; however, even with much research in the area of granular media, the physical aspects and laws that define their behavior are still an obscure matter. Various techniques and methods have been developed that use the kinetic theory and hydrodynamics to describe the properties of interest in granular medium interactions. The domain of validity of using the kinetic theory and hydrodynamics in non-elastic granular collisions is uncertain. Before the hydrodynamic theory is used to study granular materials, scientists need to find ways to measure the physical aspects of granular media.