Setting Fluid Film Models and Initial Conditions

Set the fluid film models and the initial conditions for the fluid film phases.

To set the fluid film models and initial conditions:

You first define the fluid film phases. In this tutorial, you define only one phase for water.
  1. In the Physics 1 continuum, right-click the Models > Fluid Film > Fluid Film Phases node and create a new phase.
  2. Rename the Phase 1 node to Water Film.
  3. For the Water Film phase, select the following models in order:

    Group Box

    Model

    Space

    Three-Dimensional

    Flow Model (selected automatically)

    Material

    Liquid

    Equation of State

    Constant Density

    Viscous Regime Laminar
  4. Click Close.

The expanded Water Film > Models node is shown below.



You specify the initial water thickness with a field function, as you only want film to appear initially at the top of the geometry. Assume that the initial water is 1 mm thick and covers a wall length and width of 250 mm and 200 mm, respectively.

  1. Define the field function to use for specifying the initial water thickness:
    1. Right-click the Automation > Field Functions node and select New > Scalar.
    2. Rename the User Field Function 1 node to Initial Film Thickness.
    3. Select the Initial Film Thickness node and set the following properties:
      Property Setting
      Dimensions Length
      Function Name InitialFilmThickness
      Definition (($$Centroid[0]<0.25) && ($$Centroid[2]>0.025) && ($$Centroid[2]<0.225)) ? 0.001: 0
Set the initial conditions for the fluid film.
  1. Edit the Water Film > Initial Conditions node and set the following properties:
    Node Property Setting
    Fluid Film Thickness Method Field Function
    Scalar Function Initial Film Thickness


  2. Save the simulation.