### 5.14.1. Implementation

The implementation of free surface flow in CFX is essentially the same as multiphase (homogeneous or inhomogeneous) along with some special discretization options to keep the interface sharp. These include:

- A compressive differencing scheme for the advection of volume fractions in the volume fraction equations.

- A compressive transient scheme for the volume fraction equations (if the problem is transient).

- Special treatment of the pressure gradient and gravity terms to ensure that the flow remain well behaved at the interface.

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