Mode coupling in nonequilibrium granular flow systems

In this paper we examine the role of mode coupling in nonequilibrium granular flow systems and derive mode coupling equations for equal-time multi-linear correlation functions in general nonequilibrium systems. By applying N-ordering analysis and projection operator techniques, the hierarchy of equations obtained is simplified which permits the equal-time multilinear averages to be calculated systematically. The linear and equal-time bilinear nonequilibrium correlation functions are calculated explicitly for a steady-state system characterized by a small linear shear flow and uniform number and internal energy densities.