The facility, shown below, is quite large. A schematic illustrates the important dimensions and rough layout of the device. The large white tank in the photo above is the supply section. The tank is filled with tap water, while a thick (50% by volume) slurry is fed from the platform above through a small tube to the bottom of the tank. Due to the many bends in the inlet pipe, the slurry is well-mixed when it enters the larger tank (shown empty above, though it is filled to the brim when a fan is being built).

One the biggest problems forming a realistic fan is that the flow coming out of our source must be a plume (a buoyantly-driven flow), and not a jet (an inertially-driven flow). That is the reason for the equilibration section shown in the schematic. In fact, we also have a turbulence-dampening arrangment which keeps the particles entrained while reducing the interia and turbulence in the entering flow. The arrangment consists of a box with holes drilled on both in the inlet and exit side in random locations. Within the box, styrofoam peanuts nearly fill the entire volume. When the dense, sediment-laden fluid flows in the peanuts move around keeping the sediment fluid mixed, while removing much of the energy. The result is a flow which transitions to plume within 10-20 cm of the box exit. Finally, we need a way to remove the current to prevent it from reflecting of the far walls and reworking the deposit. Most experimentalists make this space too small, but we found the 0.5 m space usually just enough to eliminate reflection. Reflections are also prevented from an exit pipe placed on the floor of the tank with appropriately drilled holes to ensure equal removal of dense fluid.

Generally our fans are made of Balotini, a type of blown silica used in sandblasting equipment. The material is cheap (less than a quarter per kg) and easily accessible. It is also highly spherical (due to its formation process) and can be obtained in highly well-sorted packages. Typically, the Balotini has a mean diameter of around 40 microns. Variations within each batch allow us to visualize where both the coarse and fine portion of the current is deposited.