Dancing of Wet Particles: Impact, Assembly and Pattern Formation
University of Bayreuth
From sand dunes to Faraday crispations, granular materials (i.e., large agglomerations of macroscopic particles) are ubiquitous in nature, industry and our daily lives with widespread applications from the prediction of natural disasters (e.g. snow avalanches and debris flows) through the enhancement of energy efficiency in industries (e.g. mining, civil engineering) to emerging new technologies (e.g. powder based additive manufacturing, or 3D printing). Due to the energy dissipation at the individual particle level, granular systems are highly dissipative and consequently their stationary states are typically far from thermodynamic equilibrium. Therefore, understanding how the interactions between individual particles influence the collective behavior is crucial in describing granular materials as a continuum.
In this talk, my recent efforts in deciphering the dynamics of partially wet granular materials (e.g., we sand for sculpturing) will be presented. From single particle bouncing to collective motion, the following questions will be addressed. At the `microscopic' level of individual particles: How to estimate the energy dissipation associated with the impact of wet particles? Can we have a prediction of the coefficient of restitution for various liquid and particle properties as well as impact velocities? At the `macroscopic' level of collective motion: How effectively `thermalized' wet particles assemble themselves into various nonequilibrium stationary states? How does particle shape matter? How liquid mediated particle-particle interactions influence the pattern-forming scenario in vibrofluidized granular materials?