Couette grain flow experiments: The effects of the coefficient of restitution, global solid fraction, and materials

Bottom wall friction coefficients on the dynamic properties of sheared granular flows

“…The local area solid fraction in each radial region can be determined as follows v i = A pi / A si , where A pi was the cross-sectional area of the particles that occupied the radial region i and A si was the area of the radial region i [5,21,26]. The ensemble averages of the tangential bV θ N and radial bV r N velocities in each radial region were obtained from approximately 1200 particles, as follows:…”

“…The slip velocity at the driving wall was determined using the following equation based on previous studies [5,21,26]:…”

“…Jasti and Higgs [21] experimentally studied granular flows in an annular shear cell and observed that particle velocity and granular temperature increased with increasing shearing wall roughness. Marinack et al [26] used different shearing wall surface materials to produce different coefficients of restitution between the granular and shearing surface materials with the same shearing wall roughness and found that the velocity and granular temperature increased with the increase of restitution coefficient. Hsiau et al [19] observed that convection and segregation rates increased with an increasing side wall friction coefficient in a vertical vibration bed.…”

Using PIV to measure granular temperature in saturated unsteady polydisperse granular flows

“…11b). In terms of material properties alone, this can be attributed to differences in the particle coefficient of restitution [37] (noting that the metal and glass particle flows result in higher T than those using PVC and polystyrene), solid fraction, presence or otherwise of viscous fluid (resulting in both viscous effects and the development of fluid pore pressure) and polydispersity. In addition external experimental arrangements, such as flow width, depth, mass, slope and basal friction can all have an influence on the granular temperature profile.…”

Estudo da segregação de material granular em tambor rotatório empregando a abordagem numérica Lagrangeana

“…Já para a superfície lateral do tambor, a qual é constituída de aço inox e apresenta espessura de 2 mm, o valor do coeficiente de restituição avaliado para a interação entre partículas de vidro e a superfície foi de 0,66. Em seu trabalho, Bharadwaj et al (2010) assumiram valor de coeficiente de restituição de 0,9 para impactos de partículas de celulose monocristalina sobre superfícies de aço, enquanto Marinack et al, (2011), avaliaram o impacto de materiais como esferas de polibutadieno, aço, cromo e tungstênio sobre superfícies planas de aço, e obtiveram valores de coeficientes de restituição variando entre 0,55 a 0,86, verificando assim que os resultados obtidos neste trabalho encontram-se de acordo com os observados na literatura.…”