For either steady-state or transient flow steps, you can specify the momentum coupling scheme and energy coupling scheme for Lagrangian particles as a one-way relationship or a two-way relationship. A one-way relationship means that the fluid flow has a momentum or thermal effect on the particles, but the particles have no effect on the fluid flow. In a two-way relationship, the fluid flow and particles have a momentum or thermal effect on each other. For transient flow steps, you can enable particle-particle interactions if you want to consider interactions between particles. When particle interactions are active, you can also specify the normal coefficient of restitution, which is the ratio of the velocity before the particles collide to the velocity after the particles collide. A coefficient of 1 describes a completely elastic collision. | |||||||||