### 7.1.4. Setup

To facilitate setting up typical domain settings for the cavitation of water, you may load a single-domain mesh, then run the template .ccl file:

CFX/etc/model-templates/cavitating_water.ccl

This file should be examined in a text editor before using it so that you understand which settings it specifies.

For the domain fluids list, specify both a liquid and a vapor for the same material. In most cases, it is sufficient to use a constant-density vapor.

Under Fluid Models for the domain, it is strongly recommended that you select Homogeneous Model under Multiphase Options. You do not need to select Free Surface Model for the purpose of simulating cavitation.

Under Fluid Pairs for the domain, select the fluid pair from the list and, for Mass Transfer, set Option to `Cavitation`. Select the Rayleigh Plesset cavitation model or a User Defined Cavitation Model. For the Rayleigh Plesset model, the Mean Diameter for cavitation bubbles represents the mean nucleation site diameter and must be specified. The default value of 2e-06 m is a reasonable value in most cases. The Saturation Pressure must be defined unless the materials you have selected are the components of a homogeneous binary mixture. In the latter case, the saturation properties will already be defined in the mixture definition, but you may still choose to override the Saturation Pressure by specifying it on the Fluid Pairs tab.

When initializing the domain, set the volume fraction of vapor to zero and the volume fraction of liquid to unity. These settings (represented by the `Automatic` setting for Volume Fraction) are used by default in CFX.

Set up the problem with one of the following boundary condition combinations:

1. Inlet total pressure and outlet mass flow (recommended)

2. Inlet velocity profile and outlet static pressure

The inlet boundary condition should specify that the volume fraction of vapor is zero.

Turbulence models should be chosen as usual (for example, k-epsilon or SST). For turbulence induced cavitation, consider using the DES model.

For advection scheme, use high resolution, or a specified blend factor of unity.

If editing a material, remember that the vapor pressure is on an absolute scale; it does not depend on the specified reference pressure.

Cavitation models cannot be combined with other types of interphase mass transfer, such as thermal phase changes.

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