Setting Initial Conditions

You set the initial conditions for the physics continuum. The initial condition for the spatial distribution of the two primary fluids in the continuum is as follows: you have only water in the left-hand chamber and only air in the right-hand chamber and channel. A convenient way of specifying such a distribution is by creating and using field functions.

To set the initial conditions:

Define the field functions to use for specifying the initial condition for the spatial distribution of the two fluids in the continuum:
  1. Right-click the Automation > Field Functions node and select New > Scalar from the pop-up menu.
  2. Rename the User Field Function 1 to Initial Distribution (Air).
  3. Select the Initial Distribution (Air) node and set the following properties:
    Property Setting
    Function Name Initial Distribution (Air)
    Definition ($${Position}[0] >= -0.001) ? 1 : 0
  4. Repeat the steps that are outlined above to specify the initial distribution of the H2O phase using a second field function named Initial Distribution (H2O) with the following definition:

    ($${Position}[0] >= -0.001) ? 0 : 1

    Since these two field functions are the inverse of each other, the water vapor concentration is zero everywhere. This value is appropriate in this case as there is no cavitation in the stationary fluids.

Set the initial conditions for the Injector continuum.
  1. Edit the Initial Conditions node and set the following properties:
    Node Property Setting
    Volume Fraction Method Composite
    Composite > Air Method Field Function
    Scalar Function Initial Distribution (Air)
    Composite > H2O Method Field Function
    Scalar Function Initial Distribution (H2O)


  2. Save the simulation.