Starting from Enskog equation of hard spheres of mass m and diameter D under the gravity g, we first derive the exact equation of motion for the equilibrium density profile at a temperature T and examine its solutions via the gradient expansion. The solutions exist only when βμ ≤ μo ≈ 21.756 in 2 dimensions and μo ≈ 15.299 in 3 dimensions, where μ is the dimensionless initial layer thickness an...

We develop the kinetic theory of dilute cohesive granular gases in which the attractive part is described by a square well potential. We derive the hydrodynamic equations from the kinetic theory with the microscopic expressions for the dissipation rate and the transport coefficients. We check the validity of our theory by performing the direct simulation Monte Carlo.

The flow characteristics of a gravity-driven dense granular flow in a granular bed with a contracted drainage orifice are studied by using discrete element method and quantitative analysis. Three values of discharging rates, ranging from fast to slow dense flows, are investigated. Time variations and derivatives of mean forces and velocities, as well as their respective correlations, are analyz...

Vibrating walls, frequently employed to maintain the temperature (i.e., average velocity) in a granular gas, modify the system strongly, rendering it dissimilar to a molecular one in various aspects. As evidenced by microgravity experiments employing a quasi-two-dimensional (quasi-2D) rectangular box and by 2D simulations, the one-peak velocity distribution is split into two, rendering the stre...

The response functions for small spatial perturbations of a homogeneous granular fluid have been described recently. In appropriate dimensionless variables, they have the form of stationary state time correlation functions. Here, these functions are expressed in terms of reduced single particle functions that are expected to obey a linear kinetic equation. The functional assumption required for...

Kinetic theory based particle velocity measurements in a symmetric two-story riser show that in the core the flow is laminar and that the granular temperature is approximately given by the analogue of thermal temperature rise in Poiseuille flow. However, like in the turbulent flow in a pipe, the normal kinetic stresses are anisotropic. The shear and the normal stresses are an order of magnitude...

Granular flow in a rotating drum is studied by experiments and by Computation Fluid Dynamics (CFD) simulations. The particulate phase is modelled based on the Continuum Eulerian Approach (CEA) in the simulation. The particulate phase CEA prediction using the common Gidaspow granular kinetic viscosity or the Syamlal-O’brien granular kinetic viscosity fails to predict the measured dynamic angle o...