The equations for the volume fractions of the dispersed phases (Equation 6-127) are solved in the Phase Transport interface. The momentum equation and the continuity equation for the mixture velocity and pressure (Equation 6-132 and Equation 6-137) are solved in the coupled laminar or turbulent single-phase flow interface. The Mixture Model multiphysics coupling feature supplies the mixture density ρ and viscosity μ to the single-phase flow interface, and the convective dispersed phase velocities to the Phase Transport interface. In addition it adds the diffusion stress term to the momentum equation (see Equation 6-137, when the Include diffusion stress in momentum equation checkbox is selected), and the diffusive term to the transport equations for the dispersed phases (see Equation 6-127). In case there are mass sources in the Phase Transport interface, the Mixture Model multiphysics feature adds the right-hand side to the mixture continuity equation (Equation 6-132).