Rate-dependent fluctuations of densely packed soft particles under continuous shearing
JC Tsai1*, JR Huang1
1Inst. of Physics, Academia Sinica, Taiwan
* Presenter:JC Tsai, email:jctsai@phys.sinica.edu.tw
We study experimentally the dynamics of centimeter-sized fully-immersed PDMS particles that are densely packed and are subject to smooth constant-speed shearing.We characterize the rate-dependent behaviors by measuring the fluctuations of boundary force. Such fluctuations allow us to identify the development of intermittency , that can otherwise be missed in the conventional time-averaged rheology. By varying the compostion of particles, we also vary their elasticity. The scenarios behind these fluctuations are also confirmed with synchronized internal imaging. Our findings suggest a rich dynamics behind the "jammed flows" of soft particles.

Keywords: flow, fluctuations, granular, jamming, rheology