THE KINETIC MODEL FOR COLLISIONAL STRESSES IN RAPID GRANULAR FLOWS
快速颗粒流碰撞应力的动理模型

Particle collisions are the main mechanism of the momentum transfer, the energy transfer and the energy dissipation for rapid granular flows. Therefore, attention is paid to the collisional stresses in the study of rapid granular flows. Based on an inelastic collisional model of uniform, smooth and spheric particles, the collisional stress tensor, the collisional energy flux and the rate of energy dissipation, which are expressed in integral forms, are all obtained in this paper by analogizing the method in the kinetic theory of gases. If the Maxwell distribution is supposed as the first order approximation of the particle velocity distribution function, the collisional stress tensor may be integrated and the corresponding second order approximation solution of the Boitzmann equation is thus obtained subsequently. The comparisons show that the present theoretical results and the experimental data for the simple shear rapid granular flows agree very well.