Selecting the Physics Models

Physics models define the primary variables of the simulation, including pressure, temperature, velocity, and what mathematical formulation is used to generate the solution.

The core physics model that this tutorial requires is the Eulerian Multiphase model which provides a full Eulerian solution for the air-water flow. The Multiple Flow Regimes portion of the setup is defined separately in a phase interaction.

To select the physics models:

  1. In the physics continuum, Continua > Physics 1, select the following models in order:

    Group Box

    Model

    Space

    Two Dimensional (pre-selected)

    Time

    Implicit Unsteady

    Material

    Multiphase

    Multiphase Interaction (selected automatically)

    Multiphase Model

    Eulerian Multiphase (EMP)

    Gradients (selected automatically)

    Viscous Regime

    Turbulent

    EMP Turbulence Phasic Turbulence (selected automatically)

    Optional Models

    Gravity

  2. Click Close.
  3. To review the models, open the Physics 1 > Models node.


You now set the appropriate properties. In a Multiple Flow Regimes simulation, you are advised to use second order convection for the Volume Fraction as well as the Flow. This setting reduces numerical diffusion and helps to obtain a reasonably sharp interface. The minimum volume fraction setting increases the robustness of the simulation.

  1. Select the Eulerian Multiphase (EMP) node and set the following properties:
    Property Setting
    Volume Fraction Convection 2nd-order
    Minimum Volume Fraction 1.0E-12
  2. Save the simulation.