The inertial number of a granular flow is a dimensionless quantity defined as where
is its magnitude, d is the average particle diameter, P is the isotropic pressure and ρ is the density.
can be interpreted as the effective viscosity of the granular material, which tends to infinity in the limit of vanishing shear flow, ensuring the existence of a yield criterion.
[1] One deficiency of the μ(I) rheology is that it does not capture the hysteretic properties of a granular material.
[1][3] Since its initial introduction, many works has been carried out to modify and improve this rheology model.
[4] This model provides an alternative approach to the Discrete Element Method (DEM), offering a lower computational cost for simulating granular flows within mixers.