# Test Case for Phase Fraction Transport by Potential

## Description

This case tests the transport of a phase fraction field according to a given
potential. Starting from homogeneous distribution, the air phase is expected
to accumulate in the centre of the domain.

Note that this transport functionality requires `globalBounds true` or a
non-zero `extremaCoeff` in the alpha solution parameters to become effective.

## Technical Information

* 2D
* No gravity
* Potential is pre-computed (see below)

## Pre-Processing

A test potential is computed via generateFields. The potential has its maximum
in the centre of the domain (value 1) and decays quadratically with the distance
from the centre point (finally approaching zero in the corners of the domain).

## Post-Processing

Line data are obtained at a horizontal line through the origin and compared to
reference data in validation directory.
