# Vertical Channel Test Case

## Description

This case tests the implementation of the virtual mass. The geometry consists of
a vertical rectangular channel with a bottom inlet and a top outlet. Air and
water are injected at the bottom inlet in equal proportions at equal velocity.
As buoyancy acts on the disperse gas bubbles, the air accelerates and the water
decelerates, while the volume fraction of the air drops.

## Technical Information

- 1D
- 80 cells, cell growth imposed to avoid oscillations
- initialised with alpha.air = alpha.water = 0.5
- inlet: alpha.air = alpha.water = 0.5, 1 m/s each
- steady-state reached after 2 s

## Post-Processing

Phase-specific velocities and air volume fraction are extracted along a vertical
line along with the evolution of the residuals of the working pressure. Data are
plotted and compared to the reference via a gnuplot script.
