Additionally to the basic boundary conditions for the Heat Transfer in Fluids and Heat Transfer in Solids and Fluids interfaces that are described in Heat Transfer in the COMSOL Multiphysics Reference Manual, the Polymer Flow Module provides boundary conditions that are tailored to model inflow and open boundary conditions for fluid flows.

At the inlet boundary of a fluid domain, the Inflow boundary condition defines a heat flux that accounts for the energy that would normally be brought by the fluid flow if the channel upstream to the inlet were modeled.

The Open Boundary condition is used to model the boundary between a fluid domain and the rest of the same fluid domain that is not represented in the geometry. At the open boundary both inflow and outflow conditions are supported.