Setting Boundary Conditions

Define the boundary types and specify the appropriate property values. The geometry that is used for this tutorial has six boundaries, three of which have no-slip wall conditions that are assigned to them. Of the remaining three boundaries, define two as pressure outlet boundaries and define the last one as a symmetry plane.

To set the boundary conditions:

  1. Rename the Default_Fluid 2D node to Fluid.
  2. Edit the Fluid > Boundaries node and set the boundary types as follows:

    Boundary

    Type

    Bottom

    Symmetry Plane

    Left

    Pressure Outlet

    Middle

    Wall

    Right

    Pressure Outlet

    TopRight

    Wall

    TopLeft

    Wall

The only boundary conditions that are specified are at the two pressure boundaries.

  1. Edit the Left > Physics Values node and set the following properties:
    Node Property Setting
    Pressure Value 5.0E7 Pa
    Volume Fraction Value [1.0, 0.0, 0.0]


    The Volume Fraction setting enforces the condition that only liquid water enters the solution domain through that boundary.

  2. Edit the Right > Physics Values node and set the following property:
    Node Property Setting
    Volume Fraction Value [0.0, 1.0, 0.0]

    This setting enforces the condition that only air enters the solution domain through that boundary.

  3. Save the simulation.