Backward Compatibility with Version 5.0 Euler-Euler Model, Laminar Flow The results from models using the Euler-Euler Model, Laminar Flow interface may differ in version 5.2a due to the more general formulation for the viscous stress in the momentum equation for the dispersed phase. The behavior in the old formulation may be reproduced by dividing the dispersed phase viscosity, μD, by the variable ee.phidPos. Transport of Concentrated Species See Chemical Reaction Engineering Module.