This program is my attempt at a fluid simulation based on the works of Matthias Müller, as explained in this video and this PDF. It visualises a circle in a wind tunnel where the wind flows from left to right. Shapes other than a circle can be defined, but tend not to work as well due to the grid based simulation. Such a fluid simulation is rather imperative by nature so implementing it in a functional language was a challenge.

To run, cabal run -O2 is recommended as the program is quite CPU intensive.

The circle can be moved by dragging the mouse.

There are several variables at the top of the file Main.hs which control the parameters of the simulation.

There are four ways of visualising the simulation:

• Smoke : inject some smoke at the left hand side and draw the smoke density at each point.
• Pressure : Visualise the pressure at each point.
• Velocity : Slightly unorthadox method of visualising the horizontal and vertical velocities at each point.
• SmokePressure : View the pressure field multiplied by the smoke field - that has the effect of showing a kind of coloured smoke based on the pressure.