The Initial Values node adds an initial value for the pressure that can serve as an initial condition for a transient simulation or as an initial guess for a nonlinear solver.

If you have the Subsurface Flow Module licensed, you can specify the pressure either directly or as an expression for the pressure head, Hp, or the hydraulic head, H; the hydraulic head and the pressure head relate to the pressure p as

where ρ is the fluid density (SI unit: kg/m3); g denotes the acceleration of gravity (SI unit: m/s2); and D is the elevation (SI unit: m).

Enter a value or expression for the initial value of the Pressure p (SI unit: Pa). The default value is 0 Pa.

In case the Subsurface Flow Module is available, click the Pressure head button to enter a value or expression for Hp (SI unit: m). The default is 0 m. Click the Hydraulic head button to enter a value or expression for H (SI unit: m). The default is 0 m.