INFORMATION BULLETIN ON RHEOSCOPIC FLUIDS
Fluids which are extremely effective in producing visual images of dynamic currents are now available from Kalliroscope Corporation. Research laboratories and teaching institutions throughout the world use them for the study and demonstration of fluid flow. The fluids are suspensions of microscopic crystalline platelets. When they are put into motion, the suspended platelets orient so as to align their larger dimensions parallel to the planes of shear. In the presence of incident light, areas of varying orientation will reflect differing intensities of light, and their evolution and movement will produce striking visual images of the currents taking place. Unlike dye-based tracers which eventually become uniformly dispersed within the medium, Kalliroscope fluids never lose their ability to make their flow patterns visible and can be used many times over.
We formulate two kinds of water-based fluids, a concentrate and a ready-to-use rheoscopic fluid. The ready-to-use type is ideal for trying out Kalliroscopic fluids for the first time, as well as for small or prototype experiments. The concentrate, typically used in the range of 1% to 5% produces a more economical working fluid, as well as one whose color and crystal concentration can be adjusted to the exact requirements of a particular experiment.
AQ-RF, a ready-to-use rheoscopic fluid, and AQ-1000, a rheoscopic concentrate, are waterbased. AQ-RF is light blue in color, fully stabilized, and formulated for viewing depths from 50 to 250 mm. For larger experiments and teaching demonstrations, AQ-1000 and filtered water will usually be the medium of choice. It is easy to use, non-toxic, and gives excellent results.
If you make up a rheoscopic fluid from AQ-1000 and water that is to remain in use for several days, we recommend the addition of a bacteriostatic stabilizer such as our ST-1000; this material is added at a 1% concentration and serves to maintain the clarity of the rheoscopic fluid over extended periods. With all of our water-based fluids, the dispersed crystals will gradually settle out due to their density. In experiments that will be carried out over a period of less than a few hours, or those that involve enough turbulence to keep the crystals in suspension, this doesn't present any problems. For experiments or installations that will take place over an extended time frame, you should incorporate some means of periodically creating enough turbulence in the in the bottom of your tank to re-disperse all settled material.