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Revisiting Johnson and Jackson boundary conditions for granular flows
AIChE Journal (2011)
  • Tingwen Li, National Energy Technology Laboratory
  • Sofiane Benyahia
In this article, we revisit Johnson and Jackson boundary conditions for granular flows. The oblique collision between a particle and a flat wall is analyzed by adopting the classic rigid-body theory and a more realistic semianalytical model. Based on the kinetic granular theory, the input parameter for the partial-slip boundary conditions, specularity coefficient, which is not measurable in experiments, is then interpreted as a function of the particle-wall restitution coefficient, the frictional coefficient, and the normalized slip velocity at the wall. An analytical expression for the specularity coefficient is suggested for a flat, frictional surface with a low frictional coefficient. The procedure for determining the specularity coefficient for a more general problem is outlined, and a working approximation is provided.
  • granular flow,
  • boundary condition,
  • two-fluid model,
  • rigid-body theory,
  • specularity coefficient
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Citation Information
Tingwen Li and Sofiane Benyahia. "Revisiting Johnson and Jackson boundary conditions for granular flows" AIChE Journal (2011)
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