Division of Natural and Applied Sciences, Duke Kunshan University, No. 8 Duke Avenue, Kunshan, Jiangsu, China 215316  e-mail: kh380@duke.edu

报告摘要：

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, our 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 (CoR) for various liquid and particle properties as well as impact velocities? Stepping further, I will show that how shock wave propagation plays a role in the energy injection and redisbribution processes and how such processes are governed by the particle-particle interactions. At the `macroscopic' level of collective motion: How effectively `thermalized' wet particles self-organize themselves into various nonequilibrium steady states? 

REFERENCES

[1] F. Gollwitzer, I. Rehberg, C. A. Kruelle and K. Huang “Coefficient of restitution for wet particles”, Phys. Rev. E, 86, 011303 (2012).
[2] T. Müller and K. Huang “Influence of the liquid film thickness on the coefficient of restitution for wet particles”, Phys. Rev. E, 93, 042904 (2016).
[3] K. Huang, G. Miao, P. Zhang, Y. Yun and R. Wei “Shock wave propagation in vibrofluidized granular materials”, Phys. Rev. E, 73, 041302 (2006).
[4] K. Huang, "Internal and surface waves in vibrofluidized granular materials: Role of cohesion", Phys.Rev. E 97, 052905 (2018)
[5] Kai Huang and Ingo Rehberg, "Period tripling causes rotating spirals in agitated wet granular layers", Phys. Rev. Lett. 107, 028001 (2011)
[6] Lorenz Butzhammer, Simeon Voelkel, Ingo Rehberg and Kai Huang, "Pattern formation in wet granular matter under vertical vibrations",  Phys.Rev. E 92, 012202 (2015)
[7] Andreas Zippelius and Kai Huang, "Density-wave fronts on the brink of wet granular condensation",  Sci. Rep. 7, 3613 (2017)

邀请人：厚美瑛 研究员 （82649089）