Granular dynamics: From radar particle tracking to pattern formation
- Date: Oct 6, 2017
- Time: 10:15 AM - 11:15 AM (Local Time Germany)
- Speaker: Dr. Kai Huang
- University of Bayreuth
- Location: Max-Planck-Institut für Dynamik und Selbstorganisation (MPIDS)
- Room: SR 0.77
- Host: DCF
- Contact: marco.mazza@ds.mpg.de
From sand dunes to Faraday crispations, granular materials, i.e., large agglomeration of macroscopic particles, are ubiquitous in nature, industry and our daily lives with widespread applications ranging 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). 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 mobility of individual particles influences the collective behavior is crucial in describing granular materials as a continuum.
At the ‘microscopic' level of individual particles, I will introduce a microwave radar system that is capable of tracking a metallic particle continuously in three dimensions and discuss its advantages and limitations in comparison to other particle imaging approaches [1]. At the `macroscopic' level of collective motion, I will talk about the pattern forming scenario of partially wet granular materials with a focus on how liquid mediated particle-particle interactions influence the collective behavior. In particularly, I will focus on the formation of density-wave fronts in an oscillated wet granular layer undergoing a gas-liquid-like transition and discuss how the emerging time and length scales are associated with the competition between the time scale for the collapse of particles due to short ranged attractive interactions and that of the energy injection resisting this process [2].
[1] Felix Ott, Stephan Herminghaus and Kai Huang, Rev. Sci. Instrum. 88, 051801 (2017)
[2] Andreas Zippelius and Kai Huang, Sci. Rep. 7, 3613 (2017). 013)
At the ‘microscopic' level of individual particles, I will introduce a microwave radar system that is capable of tracking a metallic particle continuously in three dimensions and discuss its advantages and limitations in comparison to other particle imaging approaches [1]. At the `macroscopic' level of collective motion, I will talk about the pattern forming scenario of partially wet granular materials with a focus on how liquid mediated particle-particle interactions influence the collective behavior. In particularly, I will focus on the formation of density-wave fronts in an oscillated wet granular layer undergoing a gas-liquid-like transition and discuss how the emerging time and length scales are associated with the competition between the time scale for the collapse of particles due to short ranged attractive interactions and that of the energy injection resisting this process [2].
[1] Felix Ott, Stephan Herminghaus and Kai Huang, Rev. Sci. Instrum. 88, 051801 (2017)
[2] Andreas Zippelius and Kai Huang, Sci. Rep. 7, 3613 (2017). 013)