Solving a problem in Ansys Polyflow requires that you prescribe information about the flow along the boundary of the computational domain for each sub-task. Solving a time-dependent flow also requires that you prescribe initial conditions within the domain, as discussed in Time-Dependent Flows. In addition, for viscoelastic flows, boundary conditions for the viscoelastic part of the constitutive equaintion are required at inlets. These represent the contribution to the constitutive equation from the past history of material particles entering the flow domain.

The domain of the sub-task is surrounded by closed curves (in 2D) or surfaces (in 3D) consisting of boundary sets and intersections with adjacent subdomains that are not included in the sub-task. Each of these curves or surfaces is referred to as a boundary section.