Past applications of the towing tank include dye visualization of flow past a sphere. By releasing a cloud of dye in front of a slowly-moving sphere, one can visualize wake and vortex shedding structures. Another approach is to use laser-induced fluorescence, where small amounts of fluorescent dye are added to the water. When a sheet of laser light is projected into the water, the dye fluoresces and produces an image that is photographed and analyzed.

This approach was used by Dr. Tim Johnson to provide experimental validation of a numerical simulation of low reynolds flow past a sphere. Measured parameters include length, separation points, global structure, and shedding frequencies.

IIHR's low-speed towing tank.