Colloquium
Department of Physics, NCU
A non-local μ(I) constitutive model for dense granular flows
Speaker
Prof. Fu-Ling Yang (楊馥菱)
Solid-Liquid Two-Phase Flow Lab
Mechanical Engineering, National Taiwan University
Date 2019.10.08(Tue)
Time 14:00-16:00
Place S4-625
Dense granular flows are the collective motion of solid granulates in dense configuration. Unlike Newtonian fluid, dense granular flows exhibits yield strength, non-linear relationship to flow shear strain rate, hysteresis at flow interface, and slip at flow boundary. Its rich flow behaviors result from complex transport mechanism at the grain size level as the interactions between discrete constituents are intrinsically bi-phasic and of multi-scale.
As these flows are common in natural hazards and industrial processes, a macroscopic continuum description is desired for flow prediction and control. In this talk, we shall introduce a recently renowned constitutive model in terms of an effective friction coefficient μ and a dimensionless inertial number I. However, the so-called μ(I) local rheology model needs non-local refinement to address the incoherent microscopic transport process and macroscopic dynamics, especially near the solid-liquid transition. We will present measurements on the non-locality and reveal the underlying microstructure via both discrete element simulation and Photoelastic experiments. A refined non-local description is then formulated in analogy to Landau phase transition model in view of system energy cascade and the microscopic transport features.
