Eulerian and Lagrangian particle transport with drag (Q1115750)

The linear Boltzmann equation is formulated in relative velocities against a moving background, and coupled to the Eulerian and Lagrangian continuity equations through the material divergence. Material acceleration terms are expanded locally, effective drag coefficients and moving sources are defined, and incorporated in the transport equation in consistent fashion. Standard multigroup representations for the differenced material motion and drag terms are obtained. Specific applications are presented and contrasted. The representation in relative velocites serves as a useful alternative to a formulation using effective cross sections defined against a moving background.