The Nonisothermal Flow multiphysics feature can be added to a model containing a single-phase flow and a heat transfer interface, to realize the bidirectional coupling between the two interfaces.

It is common to start a model with a single physics (for example, fluid flow), then implement the second one (for example, heat transfer). Then adding the Nonisothermal Flow multiphysics feature realizes the bidirectional coupling. It also redefines the consistent stabilization so that the multiphysics coupling effects are accounted for in the numerical stabilization.

With the Heat Transfer Module or the CFD Module, it accounts for the turbulence in the coupling. In particular, it modifies the effective thermal conductivity and implements thermal wall functions if the fluid flow model requires them. Those modifications affect the implementation of several heat transfer features. It allows to include work done by pressure changes and viscous dissipation, and Boussinesq approximation is supported. Finally some physics features are updated when the Nonisothermal Flow multiphysics feature is active. In particular, the Interior Fan and Screen fluid-flow features are updated to account for the multiphysics coupling.