Inlet
The Inlet node adds a boundary condition for the inflow (or outflow) perpendicular (normal) to the boundary. It has three options that can be used to specify inlet condition on a boundary, as follows:
Velocity
Enter a value or expression for the Normal inflow velocity U0 (SI unit: m/s). A positive value of U0 represents an inflow velocity. A negative value represents an outflow velocity. The inlet velocity boundary condition is implemented as;
where U0 is a value or expression for the specified inward (or outward) Darcy velocity. A positive value of the velocity U0 corresponds to flow into the model domain whereas a negative value represents an outflow. D is the elevation head which is set to zero for other than Subsurface Flow Module applications.
Pressure
Use the Pressure option to specify the inlet pressure on a boundary. In many cases the distribution of pressure is known, giving a Dirichlet condition p = p0 where p0 is a known pressure given as a number, a distribution, or an expression involving time, t, for example. Enter a value or expression for the Pressure p0 (SI unit: Pa).
mass flow
If you select Mass flow as the inlet condition, specify the total Mass flow rate M0 (SI unit: kg/s), or the Pointwise mass flux N0 (SI unit: kg/(m2·s)).
With Mass flow rate boundary condition, positive values correspond to flow into the model domain:
where M0 is a value or expression for the specified inward (or outward) Darcy flux.
Pointwise mass flux boundary condition, positive values correspond to flow into the model domain:
where N0 is a value or expression for the specified inward (or outward) Darcy flux.
Constraint Settings
To display this section, click the Show More Options button () and select Advanced Physics Options in the Show More Options dialog box.