The Creeping Flow (spf) interface (
) is used for simulating fluid flows at very low Reynolds numbers for which the inertial term in the Navier–Stokes equations can be neglected. Creeping flow, also referred to as Stokes flow, occurs in systems with high viscosity or small geometrical length scales (for example, in microfluidics and MEMS devices). The fluid can be compressible or incompressible, as well as Newtonian or non-Newtonian.
The main feature is the Fluid Properties node, which adds the Stokes equations and provides an interface for defining the fluid material and its properties. Except where noted below, see
The Laminar Flow Interface for all other settings.
By default, the Neglect inertial term (Stokes flow) check box is selected. If unchecked, or, if the
Turbulence model type is changed to
RANS, the inertial terms are included in the computations.
By default, the Creeping Flow interface uses P2+P1 elements
. Contrary to general laminar and turbulent single-phase flow simulations employing purely linear P1+P1 elements, P2+P1 elements are well suited for most creeping flow simulations but are not in general fully conservative. Full conservation properties and high accuracy is obtained by selecting P2+P2 or P3+P3 elements.
