The inflow condition allows you to specify a volumetric or a mass flow rate across a boundary section surrounded by other boundary sections with well-defined adhesion conditions (slip, no-slip, symmetry, and so on). The convention here is that an entering flow rate is considered positive. For example, the volumetric flow rate is given as m3/s-m for a 2D planar model and m3/s for a 3D or axisymmetric model. Similarly, the mass flow rate is given as kg/s-m for the 2D planar model and kg/s for a 3D or axisymmetric model. Flow rate is defined per unit length in the direction perpendicular to the plane of the flow.